ABSTRACT
Objective To explore the effect of different concentrations of endothelin-1 (ET-1)on the en-dogenous nitric oxide (NO)and hydrogen sulfide (H2S)pathways of vascular smooth muscle cells (A7r5 cell lines)in rats.Methods A7r5 cell lines were divided into the control group and the experimental group.ET-1 at a concentra-tion of 10 -8-10 -6 mol/L was added into the experimental group,and as for the control group,the same volume of sterile phosphate buffered saline (PBS)buffer solution was added.The content of NO and H2S in A7r5 cell lines was detected by fluorescent NO probe and H2S probe after ET-1 stimulation for 48 h,respectively.The content of NO in the supernatant was measured by NO assay kit at 48 h of the incubation.The content of H2S in the supernatant was measured by polarographic H2S sensor at 48 h of the incubation. The expressions of inducible nitric oxide synthase (NOS2),endothelial nitric oxide synthase (NOS3),cystathionine -γ -lyase (CSE),cystathionine -β -synthase (CBS)and proliferating cell nuclear antigen (PCNA)were detected by the Western blot method.Results The rela-tive fluorescence intensity of the content of NO in the A7r5 cell lines of ET-1 10 -8,10 -7 and 10 -6mol/L groups (0. 078 ± 0. 080,0.075 ± 0.002,0.056 ± 0.009)was markedly lower than that in the control group(0.094 ± 0. 061), and the differences were statistically significant(F＝15.248,P＜0.05);Compared with the control group[(2. 131 ± 0. 484)μmol/L],the content of NO in the supernatant of the experimental groups [(1.391 ± 0.134 )μmol/L, (1.219 ± 0. 280)μmol/L,(1.116 ± 0.181)μmol/L]was significantly decreased,and the differences were statistically significant(F＝20.833,P＜0.01);NOS2 protein expression(0.457 ± 0.097,0.462 ± 0.116,0.438 ± 0.180)was decreased markedly compared with that of the control group(0.721 ± 0.222),and the differences were statistically sig-nificant(F＝6.196,P＜0.01),but the expression of NOS3 showed no significant differences(F＝2.669,P＞0.05). The relative fluorescence intensity of the content of H2S in the A7r5 cell lines of ET-1 10 -8,10 -7 and 10 -6mol/L groups (0.063 ± 0.002,0.056 ± 0.008,0.042 ± 0.009)was markedly lower than that in the control group (0.082 ± 0. 006),and the differences were statistically significant(F ＝16.297,P＜0.01);Compared with the control group [(29.439 ±4.236)μmol/L],the content of H2S in the supernatant of the experimental groups [(17.516 ±5.144) μmol/L,(14.481 ± 4.885)μmol/L]was significantly decreased,and the differences were statistically significant (F＝12.518,P ＜0.01).CBS protein expression(0.359 ± 0.096,0.270 ± 0.038,0.174 ± 0.051)was decreased markedly compared with that of the control group(0.707 ± 0.107),and the differences were statistically significant (F＝20.833,P＜0.01),and the expression of CSE showed no significant differences(F＝0.708,P＞0.05).The data showed that PCNA protein expression in the 10 -7mol/L ET-1 group(0.686 ± 0.180)significantly increased com-pared with that of the control group(0.437 ± 0.191),and the difference was statistically significant (t＝ -2.840,P＜0.01).Conclusion ET-1 stimulation can lead to the proliferation of vascular smooth muscle cells and down-regu-late its endogenous NO and H2S pathways.