Fig 1.
The schematic diagram of our research.
(A) Chemical structure of BTP and the scheme of its effects in vivo. (B) The experimental design of BTP optical imaging for monitoring tumor hypoxic microenvironment in vivo in the cisplatin therapy process.
Fig 2.
The physical and cytotoxicity properties of BTP.
(A) The excitation and emission spectra of BTP; the emission spectra include two curves which are at the air and nitrogen atmospheres, corresponding to two quartz cuvettes, respectively. (B) The relationship between the pO2 and phosphoresce intensity. (C) Cytotoxicity evaluation of BTP: Trypan blue dye exclusion assay to measure the cell necrosis rate and Hoechst33342 plus PI assay to measure the cell apoptosis rate (n = 10).
Fig 3.
The phosphorescence imaging in vitro.
CT-26 cells uptake of BTP imaged using an inverted fluorescence microscope as well as a camera, including blank control, BTP under 20% O2 (BTP normoxia) and BTP under 5% O2 (BTP hypoxia). There are three columns including a bright field, a dark field and a merged field. The first column presents the bright field under an inverted microscope; the second column shows the phosphorescence images of cells as the bright field graphs without any moving, and the third one merged them.
Fig 4.
The phosphorescence imaging in vivo and immunohistochemical stain.
(A) The growth curves of CT-26 xenografts after transplantation into BALB/c nude mice treated with saline and cisplatin (n = 6). (B) The phosphorescence intensity of tumor imaging of CT-26 xenografts after transplantation into BALB/c nude mice treated with saline and cisplatin (n = 6). (C) The quantitative data curves of immunohistochemical stain of HIF-1α in tumor-bearing mice treated with saline and cisplatin, respectively (n = 3). (D) The quantitative data curves of immunohistochemical stain of VEGF in tumor-bearing mice treated with saline and cisplatin, respectively (n = 3). Saline (100 μL) or cisplatin (1 mg·kg-1, 100 μL).
Fig 5.
The BTP phosphorescence imaging for monitoring tumor hypoxic microenvironment in vivo at different time points (Days 9–21).
The cisplatin was used as an anti-tumor agent, and saline was injected as a contrast (n = 6). Scale bar = 10 mm.
Fig 6.
The BTP phosphorescence imaging between cisplatin and saline groups for monitoring tumor hypoxic microenvironment in vivo on Day 18 (n = 6).
Mice #1–6 are labeled in both cisplatin and saline treatment groups. Scale bar = 10 mm.
Fig 7.
The H&E stain of pathological sections and immunohistochemical stain of mouse HIF-1α and VEGF of tumor tissues on mice treated with saline and cisplatin.
Fig 8.
The HIF-1α/VEGF cellular signal pathway and their relationship to pO2 and BTP phosphorescence.
Table 1.
Three types in the balance of pro- and anti-angiogenesis.