Inhibitory effect of sodium valproate on proliferation of human lens epithelial cells in vitro

Objective To investigate the effect of sodium valproate(VPA) on the proliferation and cell cycle of human lens epithelial cells(HLECs) in vitro.Methods HLECs were treated with VPA in different concentrations(0.5 mmol·L-1,1 mmol·L-1,2 mmol·L-1,4 mmol·L-1).Cell proliferation was assessed by MTT assay at different time(24 hours,48 hours,72 hours).After HLECs were treated with VPA(1 mmol·L-1,2 mmol·L-1)for 48 hours,cell cycle was analyzed by flow cytometry and the expression of p21(cyclin-dependent kinase inhibitor) was detected by Western blot.Results MTT staining colorimetry showed that the HLECs proliferation was markedly inhibited and the effects was time and dose dependent when the concentration of VPA was more than 0.5 mmol·L-1.The inhibition rate of cultured lens epithelial cells(LECs) was 11.05%,21.58%,26.67% and 38.25%,respectively,in 0.5 mmol·L-1,1 mmol·L-1,2 mmol·L-1 and 4 mmol·L-1 of VPA group after 48 hours treatment(P0.05).More cultured HLECs were in the G0/G1 phase and fewer in the S phase after treated with VPA by flow cytometry,which indicated that VPA arrested the transition of HLECs from G0/G1 phase to S phase.The percentage of the LECs in the G0/G1 phase and the S phase at the dosage of 2 mmol·L-1 of VPA group was(85.40±3.90)% and(7.35±1.47)%,respectively,after 48 hours treatment,showing statistical significance compared with the control group[(53.14±1.71)% and(35.31±1.14)%,P0.05].Western blot indicated that VPA can increase the expression of p21.The average grey value of protein band was 0.582±0.082(1 mmol·L-1),0.914±0.113(2 mmol·L-1) and 0.303±0.029(control group),respectively,indicating statistical significance among groups(P0.05).Conclusion VPA arrests HLECs at G0/G1 by increasing the expression of p21,which finally inhibits the proliferation of HLECs.