RESUMO
Objective To investigate the effect of ZnO nanoparticles on the expressions of plasma membrane calcium ATPasel (PMCA1) of human lens epithelial cell B-3 (HLEB-3) at both mRNA and protein levels in the presence and absence of ultraviolet B (UVB) irradiation.Methods HLEB-3 was cultured in RPMI 1640 medium,and the cytotoxic effect of different concentrations of ZnO (0 μg · mL-1,2.5 μg · mL-1,5.0μg · mL-1,10.0 μg · mL-1) on HLEB-3 was investigated in the presence and absence of UVB irradiation.DAPI staining was used to monitor the effect of ZnO on HLECB-3 nuclei,and cell apoptosis was evaluated using annexin V-FITC/PI staining in the presence and absence of UVB irradiation.In addition,the intracellular calcium ion (Ca2 +)levels were assayed using Fluo-3/AM staining,and the expression levels of both PMCA1 mRNA and protein within HLEB-3 were detected by real-time PCR and Western blot,respectively.Results DAPI staining showed that the ZnO-treated HLEB-3 displayed a concentration-dependent apoptosis,and UVB irradiation could further aggravate the cytotoxic effect of ZnO on HLEB-3.In addition,in the presence of UVB irradiation,concentration gradient of ZnO (2.5 μg · mL-1,5.0 μg · mL-1,10.0 μg · mL-1) increased the intracellular calcium ion levels [from (156.34 ±4.59) nmol · L-1 to (173.88 ±7.17)umol · L-1,(289.02 ± 9.09) nmol · L-1,(488.36 ± 48.16) nmol · L 1,respectively] and upregulated HLEB-3 apoptosis,with statistical difference (all P ＜ 0.05).Moreover,the expression level of PMCA1 in the 2.5 μg · mL-1,5.0 μg · mL-1,10.0 μg · mL-1 ZnO-treated epithelial cells was accordingly 0.75,0.57 and 0.41 as much as that in the 0μg · mL-1 ZnO-treated cells in the absence of UVB irradiation (all P ＜ 0.05),and was accordingly 0.64,0.24 and 0.09 in the present of UVB irradiation,with significant difference (all P ＜ 0.05).Conclusion Both ZnO nanoparticle and UVB irradiation can exert cosuppression effect on HLEB-3 via calcium-mediated signaling pathway,indicating it has great potential for the treatment of posterior capsular opacification with UVB irradiation.