| Proliferative vitreoretinopathy (PVR) is a disease process that occurs in eyes with rhegmatogenous retinal detachments and trauma. It accounts for the majority of failures following retinal detachment surgery and visual impairment because of the fibroblastic proliferation in the vitreous and subsequent cellular contraction. It has been well documented that RPE cell is the main source of all the PVR cells and plays a pivotal role in the pathogenesis of PVR. How to control the abnormal behavior of RPE cells and inhibit the proliferation of all the associated cells are the key points of PVR's prevention and cure. Taxol , extracted from the bark of American pacific yew tree , is an antimitotic agent. It can promote the stabilization of the microtubule and inhibit mitosis and thereby can effectively accelerate apoptosis and control contraction,proliferation,migration. Recently, taxol,although still at the stage of research in ophthalmologic area, has been applied in the treatment of mammary cancer, lung cancer, gastric carcinoma etc. as a clinic drug which exhibit good results and few side effect。The article used hRPE cell as a target to study the biologic activity of taxol in order to explore a new drug treatment of PVR. Firstly, hRPE cells were isolated and cultured in primary manner in vitro and identified by monoclonal antibody of keratin. The primary cells were observed by phase contrast microscope every day. The typical cells were rounded with many melanin drops. The cells became fusiform and there were few melanin drops with transferring of culture. Five groups were divided : control group, and taxol groups (0.005,0.05,0.5,5ug/ml).It can be seen that the number of cells decreased as the concentration increased under light microscope. In control group and some taxol groups (0.005,0.05,0.5ug/ml) , cells sticked to culture flasks extended with the shape of shuttle or polygon. On Giemsa stained preparations, cytoplasm was abundant and there were some melanin drops in it. After immerged in 5ug/ml taxol , cells began to round up in shape as cytoplasm shrank. Some of them detached from culture flasks. Electronic microscope showed that there were abundant melanin granule and organell in cells and microvilli of cell surface in control group. However, there was a significant reduction of microvilli, margination of nucler chromatin and intact plasmalemma of 0.5ug/ml taxol group; 5ug/ml taxol group showed that there was cellular necrosis as membrane disruption and nucler cavitation that indicated the cytotoxicity increased obviously. Proliferation was determined by cell counting in a neubauer cytometer chamber and growth curves, viability was assessed by trypan blue dye exclusion. All the results showed that the control group cells proliferated better than the taxol group ones, all the cells'viability were more than 90% except the 5ug/ml taxol group(84.6%). MTT assay was used to determine cell growth inhibition. The plates were cultured for 24h and 72h and read by using a test wavelength of 497 nm. The results indicated that the inhibition rate of taxol was 20%,29%,41%,48% for 24h and 27%,34%,45%,58% for 72h. The cell cycle was studied by flow cytometer, the results indicted that the cultured hRPE cells kept proliferation well in vitro, meanwhile the cells in 0.5ug/ml taxol group were restrained in G2/M phase and apotosis peak raised. The statistical analysis showed that taxol had the significant prohibition effect to human RPE cells at the concentration of 0.005-5mg/l in vitro. ID50 of 24h and 72h was 5.24 and 3.24mg/l. It showed time-dose dependent manner of inhibition. The prohibition rate was about 50% at the concentration of 0.5mg/l, but no significant morphology alteration was found. There was no significant difference of inhibition between 0.5mg/l and 5mg/l taxol groups for 24h but for 72h. Necrosis became obviously when the concentration was increased to 5mg/l because the cytotoxicity increased either.The main cytotoxic effect of taxol is to restrain the cells in G2/M stage. T...
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