ABSTRACT
Background Rapamycin(RAPA)is a specific inhibitor of the mammalian target of rapamycin (mTOR).Researches showed that RAPA inhibits the proliferation of lens epithelium cells(LECs)and tumor cells and induces apoptosis of tumor cells.To investigate whether rapamycin has the inhibitory effect on retinal pigment epithelium(RPE)cells is very important for the prevention and management of proliferative vitreoretinopathy (PVR).Objective This study was to investigate the effects of RAPA on the proliferation and apoptosis of human RPE cells in vitro.Methods Human RPE cells(D407 strain)were cultured and passaged and then divided into regular culture group(blank control group),DMSO control group(0.1‰ DMSO +regular culture),and different concentrations RAPA-treatment groups(5,10,20,40,80,160,320 nmol/L).The proliferation(A490)of human RPE cells was detected using MTT,and the inhibitory rates of RAPA on the proliferation of RPE cells were calculated and compared among different groups at 12,24 and 48 hours.The apoptosis rates of the cells were analyzed among various groups by Hoechst staining after 12,24,48 hours.Results The inhibitory rates of RAPA on RPE cells were significantly different among various groups(F=484.451,P＜0.01)and evidently elevated in 20-320 nmol/L RAPA groups compared with DMSO control group(P ＜ 0.01).The inhibition of RAPA on the cells was considerably enhanced as the lapse of time(F=232.262,P＜0.01)with more dominant effects in 24 and 48 hours compared to 12 hours after addition of RAPA(P＜0.05-0.01).Compared with blank control group and DMSO control group,the apoptotic rates of the cells were evidently increased in 12,24,48 hours in 10 nmol/L RAPA group(all P＜0.05),and higher cellular apoptotic rates were found in 20-320 nmol/L RAPA groups(all P＜0.01).The alteration of cellular apoptotic rate showed a gradually incremental trend as the acting time of RAPA(F =625.584,P＜0.01).Karyorrhexis and mass-like density staining and chromatin substance were seen in RPE cells under the fluorescence microscope in ≥ 10 nmoL/L RAPA groups.Conclusions RAPA suppresses the proliferation and induces the apoptosis of human RPE cells in concentration-and time-dependent manner in vitro.