Puerarin, a phytoestrogen with a weak estrogenic effect, binds to estrogen receptors, thereby competing with 17β-estradiol (E2) and producing an anti-estrogenic effect. This study was to investigate whether puerarin could suppress the invasion and vascularization of E2-stimulated endometriotic tissue.
The endometriotic stromal cells (ESCs) were successfully established and their invasive ability under different treatments was assessed through a Transwell Assay. Simultaneously, matrix metallopeptidase 9 (MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1) were detected by western blotting. Vascularization of endometriotic tissues was observed by chicken chorioallantoic membrane (CAM) assay. The staining of MMP-9, intercellular adhesion molecule 1 (ICAM-1), TIMP-1, and vascular endothelial growth factor (VEGF) in grafted endometriotic tissues was examined using immunohistochemistry analysis. The purity of ESCs in isolated cells was >95%, as determined by the fluoroimmunoassay of vimentin. E2 (10−8 mol/L) promoted the invasiveness of ESCs by increasing MMP-9 accumulation and decreasing TIMP-1 accumulation. Interestingly, puerarin (10−9 mol/L) significantly reversed these effects (P<0.01). The CAM assay indicated that puerarin (10−9 mol/L) also inhibited the angiopoiesis of endometriotic tissue stimulated by the E2 (10−8 mol/L) treatment (P<0.05). Accordingly, immunohistochemistry showed that the accumulation of MMP-9, ICAM-1, and VEGF was reduced whereas that of TIMP-1 increased in the combination treatment group compared with the E2 treatment group.
Citation: Wang D, Liu Y, Han J, Zai D, Ji M, Cheng W, et al. (2011) Puerarin Suppresses Invasion and Vascularization of Endometriosis Tissue Stimulated by 17β-Estradiol. PLoS ONE 6(9): e25011. https://doi.org/10.1371/journal.pone.0025011
Editor: Jean-Marc A. Lobaccaro, Clermont Université, France
Received: June 28, 2011; Accepted: August 22, 2011; Published: September 15, 2011
Copyright: © 2011 Wang et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This work was supported by a grant from the National Natural Science Foundation of China (Project No. 30672742, 30873353, 30930113) and 973 project (2010CB933902). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
Endometriosis, a common, benign, estrogen-dependent disease affecting 3%–10% of women of reproductive age, is defined as the presence of endometrial glands and stroma outside of the uterine cavity . It is not a malignant disorder but it has similarities to a developing tumor. For instance, endometriotic cells can be both locally and distantly metastatic, that is they can attach to, invade and damage other tissues , . The initial phase of endometriosis is an invasive event that requires extracellular matrix (ECM) breakdown. The key enzymes that regulate the ECM are the matrix metalloproteinases (MMPs), and peritoneal invasion by endometrial tissue is thought to be dependent on MMPs and their corresponding tissue inhibitors of metalloproteinases (TIMPs). MMPs play a pivotal role in the cyclic changes of growth and tissue breakdown that occur in the endometrium. MMPs are usually synthesized during the proliferative phase and are stimulated by estrogen . Several studies have shown an increase in the accumulation of MMP-1, MMP-2, MMP-3, MMP-7, and MMP-9 in endometriotic tissues. Alteration of MMP-9 and MMP-2 is an important factor in the development of endometriosis , .
Vascularization of endometriotic implants is probably one of the most important factors in the invasion of other tissues by endometrial cells. Angiogenesis is controlled by a number of inducers; of particular importance is the vascular endothelial growth factor (VEGF) family, which is significant in processes characterized by both physiological and pathological angiogenesis. Accumulation of the VEGF gene in normal human endometrial cells is acutely upregulated by E2 in vitro . VEGF immunostaining has been observed in the epithelium of endometriotic implants, particularly in hemorrhagic red implants .
Most of the current medical treatments for endometriosis aim to downregulate estrogen activity. Historically, medical therapies have included contraceptive steroids, progestogens, and agonists of gonadotropin-releasing hormone (GnRH), as well as androgens and non-steroidal anti-inflammatory agents . These treatments can only be used for a limited time because of unacceptable side effects. In addition, high recurrence rates after medical treatments are the most significant problem . Therefore, exploring novel therapeutic strategies is necessary for improving the clinical management of patients with endometriosis.
Phytoestrogens exhibit estrogenic and anti-estrogenic activities both in vitro and in vivo . Puerarin, a phytoestrogen derived from the Chinese medicinal herb Radix puerariae, has been proven practical in the management of various cardiovascular disorders, alcoholism, and neurological disease . However, whether puerarin could suppress invasion and vascularization of endometriotic tissue is unknown.
Establishment of the primary ectopic ESCs
Endometriotic stromal cells (ESCs) should be stained positive with anti-vimentin-PE monoclonal antibody by fluoroimmunoassay. The negative cells could fibroblast cells, gland cells and epithelial cells. The purity of ESCs in isolated cells was >95% (Fig. 1).
Puerarin suppresses invasion of E2-stimulated ESCs
For the following experiments, 10−8 mol/L E2 and 10−9 mol/L puerarin were selected because of their efficacy on ESCs in our preliminary experiments. In Fig. 2A, 10−8 mol/L E2 showed a stimulatory effect on ESCs invasion compared with the untreated (vehicle) control cells, but the combination of E2 with puerarin reduced this effect (P<0.01).
Combination treatment of E2 with puerarin suppresses invasion (A) significantly in ESCs compared with E2 treatment alone. Western blotting (B) was performed to determine the accumulation of MMP-9 and TIMP-1 in ESCs treated with vehicle or E2 or E2 plus puerarin. **P<0.01, compared with the E2–treated cells. The results are expressed as mean ± SD, n = 6. The final concentration of E2 or puerarin was 10−8 mol/L or 10−9 mol/L respectively.
To characterize fully the anti-estrogenic effects of puerarin, we analyzed the accumulation of MMP-9 and TIMP-1 under same treatment. As shown in Fig. 2B, the accumulation of MMP-9 was increased whereas the accumulation of TIMP-1 was decreased after the E2 treatment compared with the untreated control. With the combination of E2 and puerarin treatment, the effect was significantly reversed.
Puerarin inhibits angiogenesis in CAM in vivo
To explore whether puerarin could inhibit vascularization of endometriosis tissue stimulated by E2, we tested the in vivo effect of puerarin on angiogenesis using a modified chick chorioallantoic membrane assay. E2-treated CAMs showed well-developed zones of neo-vascularization surrounding the sponge compared with vehicle treated CAM, however, CAM neovascularization was significantly suppressed by addition of puerarin (Fig. 3 A, B).
10−8 mol/L E2 or combination with 10−9 mol/L puerarin or normal saline containing 0.1% DMSO (v/v) were loaded on gelatin sponges which were loaded on the chick chorioallantoic membranes of chick embryos respectively. After 72 h incubation, 10% v/v formaldehyde was added onto the surface of CAMs to fix the blood. The disc and surrounding CAMs were incised carefully and photographed; representative photographs show the CAMs of 10−8 mol/L E2 or combination with 10−9 mol/L puerarin or normal saline containing 0.1% DMSO (v/v) treatment groups (A). Number of visible blood vessel branch points are statistically shown (B). n = 6, * P<0.05, ** P<0.01.
MMP-9, TIMP-1, ICAM-1, and VEGF immunostaining of endometriotic xenograft in CAM models
MMP-9, TIMP-1, ICAM-1, and VEGF staining of the grafts were shown in Figure 4. Treatment with E2 resulted in a stronger MMP-9, ICAM-1, and VEGF staining and weaker TIMP-1 staining. Treatment with E2+puerarin decreased MMP-9, ICAM-1, and VEGF staining and slightly increased TIMP-1 staining compared with the E2 treatment, which suggests that puerarin could suppress E2-stimulated angiogenesis of ectopic tissues by regulating the related protein molecules.
The cells with brown color represent protein positive. E2-treated xenografts show a stronger signal for MMP-9, ICAM-1, and VEGF, and a weaker signal for TIMP-1. Co-treatment with puerarin significantly suppressed this effect. −: very weak staining; +: weak staining; ++: strong staining; +++: very strong staining. n = 6. NC: Negative control, Immunostaining for untreated group slice (omitting primary antibody).
Isoflavones, as phytoestrogens, are of biological interest because they exhibit estrogenic and anti-estrogenic activities both in vitro and in vivo –. Puerarin, the main isoflavone glycoside derived from the Chinese medicinal herb Radix puerariae, has been proven practical in the management of various cardiovascular disorders, alcoholism, and neurological disease , . However, its role in treating endometriosis, an estrogen-dependent disorder, has not been well elucidated.
In this study, puerarin exhibits anti-estrogenic activity in a model of endometriosis. The findings support our hypothesis that puerarin could interfere with the invasion of ESCs and angiogenesis of ectopic tissues.
The establishment of endometriosis has been attributed to the attachment and invasion of retrograded endometrial fragments outside the uterine cavity. The endometriotic tissue is composed mainly of endometrial glands and stromal cells, as well as extracellular matrix (ECM). Given that the retrograde ESCs are responsible for the adherence and implantation of endometrium, ESCs rather than endometrial epithelial cells were used to assess the invasion of the retrograded endometrium .
MMPs can enable endometriotic tissue to digest into the ECM and underlying connective tissue. TIMPs, which affect normal and pathologic matrix remodeling, regulate the activity of MMPs. Among the different proteolytic enzymes known to degrade ECM, MMP-9 has been specifically reported to play a crucial role in the regulation of the metastatic behavior of ESCs –. The overexpression of MMP-9 and the low level of TIMP-1 were found in endometriotic lesions. For the most part, MMPs are synthesized during the proliferative phase and are stimulated by estrogen. In this study, we have demonstrated that ESC invasion through an artificial basement membrane was increased when treated with E2 (10−8 mol/L). The ability to invade the basement membrane and to migrate in response to the E2 stimulus was reduced after co-treatment of ESCs with puerarin (10−9 mol/L). Moreover, western blot showed that the alteration of MMP-9 and TIMP-1 level was the possible mechanism for the anti-metastatic action of puerarin.
Endometriosis requires estrogen for its continued growth and, if deprived of this hormone, it tends to regress. Estrogen plays a key role in stimulating adhesion, invasion, and implantation of menstrual endometrial fragments through its action on estrogen receptors (ER). Reportedly, puerarin can treat endometriosis partly by suppressing P450arom, a key enzyme for estrogen biosynthesis , . Another study showed that phytoestrogens act as aromatase inhibitors at low-concentrations .
We also focused on the suppression of endometriotic tissue angiopoiesis by puerarin. Preparation of stromal cells and epithelial glands cannot form endometriotic-like lesions in the CAM model . This occurs only when the tissue architecture of the endometrium is preserved . In the CAM model, the human endometrium was observed as highly angiogenic and, therefore, perfectly capable of stimulating blood vessel formation in the surrounding tissues. The phenomenon was more pronounced when treated with E2. This positive effect can be suppressed by co-treatment with puerarin. Related proteins, including ICAM-1, TIMP-1, MMP-9, and VEGF, are involved in the process.
Angiogenesis is a vital process in the development of endometriotic implants, providing substantial background for their further maintenance and growth. High levels of estrogen in the microenvironment of endometriotic lesions stimulate specific angiogenic growth factors such as VEGFs and ICAM-1. ICAM-1 has previously been linked to VEGF-dependent revascularization, and they both play important roles in pathological process in endometrial tissue , . Our data show 10−9 mol/L of puerarin can significantly inhibit the effects of estrogen on angiogenesis during lesion implantation.
The current standard medical treatments for endometriosis include GnRH agonists, contraceptive steroids, progestogens, and androgens –, all of which aim to lower circulating E2 concentrations. Of these agents, GnRH agonists appear are the most effective, but they are expensive and long-term treatment is not possible because of the loss of bone mineral density. Progestogens have the best clinical profile and a good cost-effectiveness balance; however, most studies found that they are not as effective as GnRH agonists. Oral contraceptives are only effective during treatment and have a high relapse rate after therapy is completed. Markedly high recurrence rates of up to 45% after current medical or surgical therapy have been reported . Therefore, exploring new strategies for treating endometriosis is needed.
Clinically, the potential advantages for puerarin to treat endometriosis are as follows; first, puerarin is able to bind to ER-alpha and ER-beta , it can suppress P450arom activity as aromatase inhibitors in endometriosis treatment, and it may be applicable as an adjuvant to the current medical treatments. Second, because puerarin can be used for long periods without severe side effects, medical treatment with this agent is a good option for avoiding disease relapse after the initial surgical and/or medical therapy. Third, with weak estrogen agonists/antagonists and some other enzymatic activities, puerarin is increasingly advocated as a natural alternative to estrogen replacement therapy and is available as dietary supplements.
In summary, we demonstrated that puerarin has anti-estrogenic activity by interfering with the invasion of ESCs and angiogenesis of ectopic tissues. These findings suggest that puerarin may be a new and efficient product for the medical treatment of endometriosis.
Materials and Methods
Tissue collection and cell culture
ESCs were obtained from premenopausal patients who had undergone salpingo-oophorectomy or evisceration for ovarian endometriotic cysts (n = 6). All patients had been free of any hormonal treatments before the operation. All the samples were obtained in the proliferative phase of the cycle, which was confirmed histologically. This study was approved by the human investigation committee of the Changhai Hospital, and written informed consent was obtained from all patients.
The tissues were collected under sterile conditions and transported to the laboratory on ice in Dulbecco's modified Eagle's medium (DMEM) (PAA, Linz, Austria). The ESCs were isolated as described by Kaei Nasul  and cultured in flasks with DMEM containing 10% charcoal stripped fetal bovine serum (FBS) (Biological Industries, Israel), 100 IU/mL penicillin, and 100 IU/mL streptomycin, which were then incubated in 5% CO2 at 37°C. For CAM experiments, tissue specimens were minced to fragments of 2×2 mm using a scalpel in a sterile petri dish. Tissue fragments that appeared to be necrotic were discarded.
The purity of ESCs in isolated cells cultured on a cover slip was determined by fluoroimmunoassay of vimentin (mouse anti-vimentin-PE monoclonal antibody, Thermo, Germany) as previously described . Isotype mouse IgG1 PE (eBiosicence, USA) was used as the control. The purity was calculated by vimentin-stained cells in comparison with DAPI-stained cells.
ESCs invasion was assayed in transwell chambers (Costar, USA) according to the manufacturer's instruction. Briefly, transwell chambers with 6.5 mm polycarbonate filters of 8-µm pore size were used. ESCs were starved overnight in serum-free medium containing 0.1% BSA prior to initiation of the invasion assay. The upper surface of the filter was coated with 20 µl 10 mg/ml Matrigel (Beckon Dickinson Labware, USA). The number of cells was adjusted to 5×105/ml in DMEM containing 0.1% charcoal stripped BSA, and 5×104 cells was added to the top well after Matrigel was polymerized. 600 µl DMEM containing 10% charcoal stripped FBS was added to the bottom well. Cells were treated with 1×10−8 mol/L E2 (Sigma, NY, USA) or a combination with 1×10−9 mol/L puerarin (Sigma, NY, USA) or normal saline containing 0.1% DMSO (v/v) for 12 h, the non-invaded cells were completely wiped out with a cotton swab, and the lower surface of the filter was fixed in methanol, stained with HE, and counted under a microscope at a magnification of 200× with a Leica Qwin system (Leica, Germany). For each test, the cells in 5 randomly selected fields were determined, and the counts were averaged. The results were from 6 independent experiments (n = 6).
Western blot analysis
To clarify whether puerarin could affect the levels of MMP-9 and TIMP-1 protein, ESCs were treated with above treatments at 37°C for 48 h. After the treatment procedures, cells were washed by pre-cooled PBS and lysed RIPA buffer (50 mmol/L Tris–Cl pH 7.4, 150 mmol/L NaCl, 1% NP-40, 0.1% SDS, 0.5% sodium deoxycholate) supplemented with 1 mmol/L PMSF. Protein concentration was determined using the BCA™ protein assay kit (Pierce, IL). 30 µg protein samples were resolved by SDS-PAGE and transferred to a polyvinylidene difluoride membrane (Millipore, MA). MMP-9 and TIMP-1 protein were detected by immunoblot with anti-MMP-9 and anti- TIMP-1 polyclonal antibody (Santa Cruz, CA) at a 1∶500 dilution or β-actin (1∶5000; Sigma, USA), then followed by incubation with peroxidase-coupled secondary antibodies. A Supersignal kit (Pierce, IL) was used to visualize the bands according to the manufacturer's instructions. Six independent experiments were assessed (n = 6).
Chick Chorioallantoic Membrane (CAM) Assay
The in vivo puerarin anti-estrogenic effect on angiogenesis of ectopic lesions was evaluated using the CAM vessel development assay with modifications as previously described . Fertilized chicken eggs were incubated in a standard egg incubator at 37°C and 60%–70% relative humidity for 6 days. A circular window 1.5–2 cm in diameter was opened aseptically on the eggshell, and minced tissue fragment was grafted into CAM. The window was sealed with Para film and the eggs were replaced to the incubator. After 24 h, the eggs were randomly assigned into three groups and treated with a gelatin sponge (4×4×4 mm) which was saturated with 10−8 mol/L E2 or combination with 10−9 mol/L puerarin or normal saline containing 0.1% DMSO (v/v). After 72 h the area around the loaded gelatin sponge was photographed using a Canon digital camera. The angiogenic index was defined as the mean number of visible blood vessel branch points within the defined area of the gelatin sponge. Assays for each test sample were carried out using 6 eggs.
For immunohistochemistry, 5 µm paraffin sections of CAM xenograft tissues were prepared and pretreated at 65°C for 2 hours, followed by deparaffinization. Antigen retrieval was carried out before application of the primary antibodies (MMP-9, TIMP-1, ICAM-1, and VEGF; 1∶1000 dilution; Santa Cruz, CA, USA) overnight at 4°C. Thereafter, the slides were incubated for 2 hours at room temperature with the secondary antibodies conjugated with horseradish peroxidase (HRP; 1∶100; DAKO, Japan). HRP activity was detected using the Liquid DAB+Substrate Chromogen System (DAKO, Japan). Finally, the sections were counterstained with hematoxylin and photographed.
Zhifan Lu (born on Jan.23, 1995, the 11th grade student, No. 1 High School Affiliated to East China Normal University) is interested in biological science and did some volunteer work in this research during his summer vacation in 2010.
Conceived and designed the experiments: JN ZC CY. Performed the experiments: DW YL JH LY. Analyzed the data: MJ WC MH. Contributed reagents/materials/analysis tools: DZ LX. Wrote the paper: ZC DW.
- 1. Olive DL, Schwartz LB (1993) Endometriosis. N Engl J Med 328: 1759–1769.DL OliveLB Schwartz1993Endometriosis.N Engl J Med32817591769
- 2. Bruner KL, Matrisian LM, Rodgers WH, Gorstein F, Osteen KG (1997) Suppression of matrix metalloproteinases inhibits establishment of ectopic lesions by human endometrium in nude mice. J Clin Invest 99: 2851–2857.KL BrunerLM MatrisianWH RodgersF. GorsteinKG Osteen1997Suppression of matrix metalloproteinases inhibits establishment of ectopic lesions by human endometrium in nude mice.J Clin Invest9928512857
- 3. Collette T, Maheux R, Mailloux J, Akoum A (2006) Increased expression of matrix metalloproteinase-9 in the eutopic endometrial tissue of women with endometriosis. Hum Reprod 21: 3059–3067.T. ColletteR. MaheuxJ. MaillouxA. Akoum2006Increased expression of matrix metalloproteinase-9 in the eutopic endometrial tissue of women with endometriosis.Hum Reprod2130593067
- 4. Bruner KL, Eisenberg E, Gorstein F, Osteen KG (1999) Progesterone and transforming growth factor-beta coordinately regulate suppression of endometrial matrix metalloproteinases in a model of experimental endometriosis. Steroids 64: 648–653.KL BrunerE. EisenbergF. GorsteinKG Osteen1999Progesterone and transforming growth factor-beta coordinately regulate suppression of endometrial matrix metalloproteinases in a model of experimental endometriosis.Steroids64648653
- 5. Shifren JL, Tseng JF, Zaloudek CJ, Ryan IP, Meng YG, et al. (1996) Ovarian steroid regulation of vascular endothelial growth factor in the human endometrium: implications for angiogenesis during the menstrual cycle and in the pathogenesis of endometriosis. J Clin Endocrinol Metab 81: 3112–3118.JL ShifrenJF TsengCJ ZaloudekIP RyanYG Meng1996Ovarian steroid regulation of vascular endothelial growth factor in the human endometrium: implications for angiogenesis during the menstrual cycle and in the pathogenesis of endometriosis.J Clin Endocrinol Metab8131123118
- 6. Donnez J, Smoes P, Gillerot S, Casanas-Roux F, Nisolle M (1998) Vascular endothelial growth factor (VEGF) in endometriosis. Hum Reprod 13: 1686–1690.J. DonnezP. SmoesS. GillerotF. Casanas-RouxM. Nisolle1998Vascular endothelial growth factor (VEGF) in endometriosis.Hum Reprod1316861690
- 7. Nasu K, Nishida M, Ueda T, Takai N, Bing S, et al. (2005) Bufalin induces apoptosis and the G0/G1 cell cycle arrest of endometriotic stromal cells: a promising agent for the treatment of endometriosis. Mol Hum Reprod 11: 817–823.K. NasuM. NishidaT. UedaN. TakaiS. Bing2005Bufalin induces apoptosis and the G0/G1 cell cycle arrest of endometriotic stromal cells: a promising agent for the treatment of endometriosis.Mol Hum Reprod11817823
- 8. Bergqvist A, SCANDET Group (2000) A comparative study of the acceptability and effect of goserelin and nafarelin on endometriosis. Gynecol Endocrinol 14: 425–432.A. BergqvistSCANDET Group2000A comparative study of the acceptability and effect of goserelin and nafarelin on endometriosis.Gynecol Endocrinol14425432
- 9. Boonchird C, Mahapanichkul T, Cherdshewasart W (2010) Differential binding with ERalpha and ERbeta of the phytoestrogen-rich plant Pueraria mirifica. Braz J Med Biol Res 43: 195–200.C. BoonchirdT. MahapanichkulW. Cherdshewasart2010Differential binding with ERalpha and ERbeta of the phytoestrogen-rich plant Pueraria mirifica.Braz J Med Biol Res43195200
- 10. Hwang YP, Jeong HG (2008) Mechanism of phytoestrogen puerarin-mediated cytoprotection following oxidative injury: estrogen receptor-dependent up-regulation of PI3K/Akt and HO-1. Toxicol Appl Pharmacol 233: 371–381.YP HwangHG Jeong2008Mechanism of phytoestrogen puerarin-mediated cytoprotection following oxidative injury: estrogen receptor-dependent up-regulation of PI3K/Akt and HO-1.Toxicol Appl Pharmacol233371381
- 11. Katzenellenbogen BS, Ferguson ER, Lan NC (1997) Fundamental differences in the action of estrogens and antiestrogens on the uterus: comparison between compounds with similar duration of action. Endocrinology 100: 1252–1259.BS KatzenellenbogenER FergusonNC Lan1997Fundamental differences in the action of estrogens and antiestrogens on the uterus: comparison between compounds with similar duration of action.Endocrinology10012521259
- 12. Folman Y, Pope GS (1966) The interaction in the immature mouse of potent oestrogens with coumestrol, genistein and other utero-vaginotrophic compounds of low potency. J Endocrinol 34: 215–225.Y. FolmanGS Pope1966The interaction in the immature mouse of potent oestrogens with coumestrol, genistein and other utero-vaginotrophic compounds of low potency.J Endocrinol34215225
- 13. Wang C, Kurzer MS (1997) Phytoestrogen concentration determines effects on DNA synthesis in human breast cancer cells. Nutr Cancer 28: 236–247.C. WangMS Kurzer1997Phytoestrogen concentration determines effects on DNA synthesis in human breast cancer cells.Nutr Cancer28236247
- 14. Collins BM, McLachlan JA, Arnold SF (1997) The estrogenic and antiestrogenic activities of phytochemicals with the human estrogen receptor expressed in yeast. Steroids 62(4): 365–372.BM CollinsJA McLachlanSF Arnold1997The estrogenic and antiestrogenic activities of phytochemicals with the human estrogen receptor expressed in yeast.Steroids624365372
- 15. Overstreet DH, Keung WM, Rezvani AH, Massi M, Lee DY (2003) Herbal remedies for alcoholism: promises and possible pitfalls. Alcohol Clin Exp Res 27: 177–185.DH OverstreetWM KeungAH RezvaniM. MassiDY Lee2003Herbal remedies for alcoholism: promises and possible pitfalls.Alcohol Clin Exp Res27177185
- 16. Xu X, Zhang S, Zhang L, Yan W, Zheng X (2005) The Neuroprotection of puerarin against cerebral ischemia is associated with the prevention of apoptosis in rats. Planta Med 71: 585–591.X. XuS. ZhangL. ZhangW. YanX. Zheng2005The Neuroprotection of puerarin against cerebral ischemia is associated with the prevention of apoptosis in rats.Planta Med71585591
- 17. Wang Y, Yu J, Luo X, Wang X, Li M, et al. (2010) Abnormal regulation of chemokine TECK and its receptor CCR9 in the endometriotic milieu is involved in pathogenesis of endometriosis by way of enhancing invasiveness of endometrial stromal cells. Cell Mol Immunol 7: 51–60.Y. WangJ. YuX. LuoX. WangM. Li2010Abnormal regulation of chemokine TECK and its receptor CCR9 in the endometriotic milieu is involved in pathogenesis of endometriosis by way of enhancing invasiveness of endometrial stromal cells.Cell Mol Immunol75160
- 18. Szamatowicz J, Laudański P, Tomaszewska I (2002) Matrix metalloproteinase-9 and tissue inhibitor of matrix metalloproteinase-1: a possible role in the pathogenesis of endometriosis. Hum Reprod 17: 284–288.J. SzamatowiczP. LaudańskiI. Tomaszewska2002Matrix metalloproteinase-9 and tissue inhibitor of matrix metalloproteinase-1: a possible role in the pathogenesis of endometriosis.Hum Reprod17284288
- 19. Shaco-Levy R, Sharabi S, Benharroch D, Piura B, Sion-Vardy N (2008) Matrix metalloproteinases 2 and 9, E-cadnerin, and beta-catenin expression in endometriosis, low-grade endometrial carcinoma and non-neoplastic eutopic endometrium. Eur J Obstet Gynecol Reprod Biol 139: 226–232.R. Shaco-LevyS. SharabiD. BenharrochB. PiuraN. Sion-Vardy2008Matrix metalloproteinases 2 and 9, E-cadnerin, and beta-catenin expression in endometriosis, low-grade endometrial carcinoma and non-neoplastic eutopic endometrium.Eur J Obstet Gynecol Reprod Biol139226232
- 20. Paul S, Sharma AV, Mahapatra PD, Bhattacharya P, Reiter RJ, et al. (2008) Role of melatonin in regulating matrix metalloproteinase-9 via tissue inhibitors of metalloproteinase-1 during protection against endometriosis. J Pineal Res 44: 439–449.S. PaulAV SharmaPD MahapatraP. BhattacharyaRJ Reiter2008Role of melatonin in regulating matrix metalloproteinase-9 via tissue inhibitors of metalloproteinase-1 during protection against endometriosis.J Pineal Res44439449
- 21. Han YJ, Kim HN, Yoon JK, Yi SY, Moon HS, et al. (2009) Haplotype analysis of the matrix metalloproteinase-9 gene associated with advanced-stage endometriosis. Fertil Steril 91: 2324–2330.YJ HanHN KimJK YoonSY YiHS Moon2009Haplotype analysis of the matrix metalloproteinase-9 gene associated with advanced-stage endometriosis.Fertil Steril9123242330
- 22. Yu C, Li Y, Chen H, Yang S, Xie G (2008) Decreased expression of aromatase in the Ishikawa and RL95-2 cells by the isoflavone, puerarin, is associated with inhibition of c-jun expression and AP-1 activity. Food Chem Toxicol 46: 3671–3676.C. YuY. LiH. ChenS. YangG. Xie2008Decreased expression of aromatase in the Ishikawa and RL95-2 cells by the isoflavone, puerarin, is associated with inhibition of c-jun expression and AP-1 activity.Food Chem Toxicol4636713676
- 23. Li YW, Cai ZL, Shen W, Yang SS, Yu CQ (2008) Regulation of aromatase P450 expression by puerarin in endometrial cell line RL95-2. Zhong Xi Yi Jie He Xue Bao 6: 1017–1023.YW LiZL CaiW. ShenSS YangCQ Yu2008Regulation of aromatase P450 expression by puerarin in endometrial cell line RL95-2.Zhong Xi Yi Jie He Xue Bao610171023
- 24. Rice S, Mason HD, Whitehead SA (2006) Phytoestrogens and their low dose combinations inhibit mRNA expression and activity of aromatase in human granulose-luteal cell. J Steroid Biochem Mol Biol 101: 216–225.S. RiceHD MasonSA Whitehead2006Phytoestrogens and their low dose combinations inhibit mRNA expression and activity of aromatase in human granulose-luteal cell.J Steroid Biochem Mol Biol101216225
- 25. Nap AW, Groothuis PG, Demir AY, Maas JW, Dunselman GA, et al. (2003) Tissue integrity is essential for ectopic implantation of human endometrium in the chicken chorioallantoic membrane. Hum Reprod 18: 30–34.AW NapPG GroothuisAY DemirJW MaasGA Dunselman2003Tissue integrity is essential for ectopic implantation of human endometrium in the chicken chorioallantoic membrane.Hum Reprod183034
- 26. Sillem M, Hahn U, Coddington CC 3rd, Gordon K, Runnebaum B, et al. (1996) Ectopic growth of endometrium depends on its structural integrity and proteolytic activity in the cynomolgus monkey (Macaca fascicularis) model of endometriosis. Fertil Steril 66: 468–473.M. SillemU. HahnCC Coddington 3rdK. GordonB. Runnebaum1996Ectopic growth of endometrium depends on its structural integrity and proteolytic activity in the cynomolgus monkey (Macaca fascicularis) model of endometriosis.Fertil Steril66468473
- 27. Moromizato Y, Stechschulte S, Miyamoto K, Murata T, Tsujikawa A, et al. (2000) CD18 and ICAM-1-dependent corneal neovascularization and Inflammation after limbal Injury. Am J Pathol 157: 1277–1281.Y. MoromizatoS. StechschulteK. MiyamotoT. MurataA. Tsujikawa2000CD18 and ICAM-1-dependent corneal neovascularization and Inflammation after limbal Injury.Am J Pathol15712771281
- 28. Defrère S, Van Langendonckt A, Moulin P, Befahy P, Gonzalez D, et al. (2005) Human endometrial epithelial cells (EEC) constitutively express more intercellular adhesion molecule(ICAM)-1 than endometrial stromal cells (ESC) in culture. Am J Reprod Immunol 54: 5–12.S. DefrèreA. Van LangendoncktP. MoulinP. BefahyD. Gonzalez2005Human endometrial epithelial cells (EEC) constitutively express more intercellular adhesion molecule(ICAM)-1 than endometrial stromal cells (ESC) in culture.Am J Reprod Immunol54512
- 29. Lessey BA (2000) Medical management of endometriosis and infertility. Fertil Steril 73: 1089–1096.BA Lessey2000Medical management of endometriosis and infertility.Fertil Steril7310891096
- 30. Rice VM (2002) Conventional medical therapies for endometriosis. Ann N Y Acad Sci 955: 343–352.VM Rice2002Conventional medical therapies for endometriosis.Ann N Y Acad Sci955343352
- 31. Valle RF, Sciarra JJ (2003) Endometriosis: treatment strategies. Ann N Y Acad Sci 997: 229–239.RF ValleJJ Sciarra2003Endometriosis: treatment strategies.Ann N Y Acad Sci997229239
- 32. Olive DL, Lindheim SR, Pritts EA (2004) New medical treatments for endometriosis. Best Pract Res Clin Obstet Gynaecol 18: 319–328.DL OliveSR LindheimEA Pritts2004New medical treatments for endometriosis.Best Pract Res Clin Obstet Gynaecol18319328
- 33. Practice Committee of the American Society for Reproductive Medicine (2004) Endometriosis and infertility. Fertil Steril 81: 1441–1446.Practice Committee of the American Society for Reproductive Medicine2004Endometriosis and infertility.Fertil Steril8114411446
- 34. Bergqvist A, SCANDET Group (2000) A comparative study of the acceptability and effect of goserelin and nafarelin on endometriosis. Gynecol Endocrinol 14: 425–432.A. BergqvistSCANDET Group2000A comparative study of the acceptability and effect of goserelin and nafarelin on endometriosis.Gynecol Endocrinol14425432
- 35. Wang Y, Yu J, Luo X, Li M, Wang L, et al. (2010) Abnormal regulation of chemokine TECK and its receptor CCR9 in the endometriotic milieu is involved in pathogenesis of endometriosis by way of enhancing invasiveness of endometrial stromal cells. Cell Mol Immunol 7: 51–60.Y. WangJ. YuX. LuoM. LiL. Wang2010Abnormal regulation of chemokine TECK and its receptor CCR9 in the endometriotic milieu is involved in pathogenesis of endometriosis by way of enhancing invasiveness of endometrial stromal cells.Cell Mol Immunol75160
- 36. Richardson M, Sing G (2003) Observations on the use of the avian chorioallantoic membrane (CAM) model in investigations into angiogenesis. Curr Drug Targets Cardiovasc Haematol Disord 3: 155–185.M. RichardsonG. Sing2003Observations on the use of the avian chorioallantoic membrane (CAM) model in investigations into angiogenesis.Curr Drug Targets Cardiovasc Haematol Disord3155185