Objective To study the effect of hypoxia on proliferation of cultured bovine retinal pigment epithelium (RPE) cells and expression of the antiapoptotic protein bcl-2. Methods The bovine RPE cells were cultured under normal and hypoxic chamber respectively. After 24 hours, the proliferation of RPE cells was evaluated by［3-(4,5-dimethylthiazole-2yl)-2,5-diphenyl tetrazolium bromide, MTT］test. At the same time, anti-bcl-2 protein antibody was examined by immuno-histochemistry method. Results The A value in the hypoxia group was higher than that in the normal group after 24 hours (P＜0.05 )in MTT-test. Positive staining for anti-bcl-2 protein antibody was seen in 72.6% cells in hypoxia group and 38.64% in normal group. The positive staining was more obvious near the nucleus, and fine granules scattered in cytoplasm of some cells. Conclusion Hypoxia can stimulate the proliferation of RPE cells and expression of antiapoptotic protein bcl-2. The results indicate that bcl-2 may play an important role in mediating the proliferation activity of RPE cells. (Chin J Ocul Fundus Dis, 2002, 18: 293-295)
Silicon carbide (SiC) film and silicon dioxide (SiO2) film were deposited on the surface of carbon/carbon composite (C/C) by low pressure chemical vapor deposition (LPCVD). The biocompatibility of the three carbon-based composites, e. g. C/C, C/C-SiC, C/C-SiO2 were investigated by cytotoxicity test, cell direct contact and cell adhesion experiments. Cytotoxicity, cell direct contact and cell adhesion showed that the three materials had no toxic effect on mouse fibroblasts (L929 cells). However, the particles dropped off from the three materials had a great impact on evaluation accuracy of the thiazolyl blue (MTT) test. More the particles were lost, more growth inhibition to L929 cells. The evaluation accuracy of MTT method can be kept with the filtered extract of materials. Furthermore, the results of surface particles shedding experiment showed that the amount of surface particles shed from C/C-SiO2 was the most, followed by C/C and C/C-SiC in 72 hours. Particles shedding curves showed there was a peak reached at eighth hour and then declined to the thirty-sixth hour. The filtrate analysis showed that there was no ion exchange between the three materials and simulated body fluid (SBF) solution. The results of this study on biocompatibility of carbon-based composites have certain guiding significance for their future application in clinical filed.