RESUMO
Aim To investigate the effects of endogenous and exogenous hydrogen sulfide(H_2S)on the proliferation and apoptosis of human fetal lung fibroblasts.Methods Human fetal lung fibroblasts were cultured under 2% O2～93% N_2～5% CO_2 for 24 h to produce hypoxia.Cells were divided into 6 groups:(1)Hypoxia group(N_2);(2)N_2+600 μmol·L~(-1) NaHS group;(3)N_2+1 200 μmol·L~(-1) NaHS group;(4)N_2+6 400 μmol·L~(-1) NaHS group;(5)N_2+400 μmol·L~(-1) cysteine(Cys)group;(6)N_2+200 μmol·L~(-1) S-adenosyl-L-methionine(SAM)group.After they were cultured for 24 h, MTT assay was used to evaluate the cell proliferation, and flow cytometry was used to detect cell apoptosis.Results Compared with N_2 group, 600 and 1 200 μmol·L ~(-1) NaHS(H_2S donor)significantly reduced proliferation induced by hypoxia of human fetal lung fibroblasts(P <0.01)without effects on apoptotic rates of cells(P >0.05)and 6 400 μmol·L~(-1) NaHS increased apoptosis of human fetal lung fibroblasts during hypoxia significantly(P <0.05), although no effects were found on proliferation of cells(P >0.05).In addition, Cys, substrate of cystathionine β-synthetase(H2S synthase, CBS) or SAM(activator of CBS)did not affect proliferation of human fetal lung fibroblasts induced by hypoxia(P >0.05), whereas apoptotic rates were increased significantly compared with that of N_2 group(P <0.05).Conclusions Endogenous and exogenous hydrogen sulfide can inhibit proliferation induced by hypoxia and promote apoptosis of human fetal lung fibroblasts, suggesting endogenous hydrogen sulfide may play a protective role through lung fibroblasts by inhibiting the pulmonary vascular structural remodeling caused by hypoxia.