Fig 1.
Diagram for the animal model procedure.
Timed-pregnant mice at 14.5 dpc were injected intraperitoneally (i.p.) with LPS with or without NaHS at different doses in 100μl NS twice a day at 8:30 and 11:30. Labor time was considered as the first pup was delivered. GD: gestational day. Black arrow: LPS i.p. Grey arrow: NaHS i.p. White arrow: NS i.p.
Table 1.
Injection of LPS induced preterm labor of mice.
Table 2.
NaHS delayed the onset of LPS-induced preterm labor.
Fig 2.
NaHS reverses the LPS-induced leukocytes infiltration into decidua.
Total density of leukocytes in mice maternal-fetus unit was determined by immunostaining for CD45 (common leukocyte antigen). A. Mice injected with vehicle at 14.5 dpc. B. Mice injected with NaHS(10mg/kg) at 14.5 dpc. C. Mice injected with LPS (0.4mg/kg) at 14.5 dpc. D. Mice injected with LPS (0.4mg/kg) and NaHS (10mg/kg) at 14.5 dpc. Arrow heads indicate positively stained leucocytes. Dec, decidua; Pla, placenta; Myo, myometrium.
Fig 3.
NaHS decreases maternal circulatory levels of cytokines and chemokines in LPS-induced preterm labor mice.
The blood was harvested when the LPS-injected mice delivered the first pup. Serum was collected after centrifuge. ELISA was employed to determine the concentration of IL-1β (A), IL-6 (B), TNF-α (C), CCL-2 (D) and CXCL-15 (E). Data are presented as mean ± SEM. N = 6 (vehicle and NaHS groups) or 10 (LPS and LPS+NaHS groups).*P<0.05, **P<0.01, ***P<0.001 compared with vehicle control group, #P<0.05, ### P<0.001 compared with LPS-injected group.
Fig 4.
The effect of NaHS on the mRNA expression of cytokines and chemokines in myometrium of the normal pregnant and LPS-induced preterm labor mice.
Mice accepted two i.p. injections of NS or LPS (0.4mg/kg) with or without NaHS (10mg/kg) at 14.5 dpc. The myometrium was harvested when the LPS-injected mice delivered the first pups. The mRNA levels of IL-1β (A), IL-6 (B), TNF-α (C), CCL-2 (D), and CXCL-15 (E) were measured by real-time RT-PCR and normalized by β-actin. Values are presented as mean ± SEM. N = 6 (vehicle and NaHS groups) or 10 (LPS and LPS+NaHS groups). * P<0.05, **P<0.01 compared with vehicle control, #: P<0.05 compared with LPS-injected group.
Fig 5.
The effect of NaHS on the mRNA expression of cytokines and chemokines in placenta of the normal pregnant and LPS-induced preterm labor mice.
The placenta was harvested when the LPS-injected mice delivered the first pups. The mRNA levels of IL-1β (A), IL-6 (B), TNF-α (C), CCL-2 (D), and CXCL-15 (E) were measured by real-time RT-PCR and normalized by β-actin. Values are presented as mean ± SEM. N = 6 (vehicle and NaHS groups) or 10 (LPS and LPS+NaHS groups). * P<0.05, **P<0.01 compared with vehicle control, #: P<0.05 compared with LPS-injected group.
Fig 6.
NaHS attenuates LPS-induced activation of ERK1/2 and p65 in myometrium.
The uterine tissues were harvested 1h, 2h, 4h and 5h after LPS and/or NaHS injection. The levels of phosphorylated p65, p65, phosphorylated ERK1/2 and ERK1/2 were determined by western blotting. Phosphorylated p65 (A) and ERK1/2 (B) were normalized by p65 and ERK1/2. Values are presented as mean ± SEM. N = 4. * P<0.05, **P<0.01 compared with vehicle control group, #P<0.05, ##P<0.01 compared with LPS-injected group.