Protective effects of selenium on nitric oxide mediated myocardial apoptosis

Abstract

Objective To investigate the protective effects of selenium on nitric oxide(NO)-mediated myocardial apoptosis. Methods The AC16 cardiomyocyte cultured in vitro were divided into control group, selenium treatment group, sodium nitroprusside (SNP) treatment group and selenium+SNP treatment group, SNP was the exogenous NO donor. There was no intervention in the control group, and an equal volume of the culture solution was added to the treatment groups. The selenium treatment group added a dose of 100 μg/L of selenium, the SNP treatment group added a dose of 1.0 mmol/L of SNP, and the selenium+SNP treatment group was pretreated by 100 μg/L selenium for 4 h followed by 1.0 mmol/L SNP; the cells or supernatants were collected after 24 h of culture. The content of NO was detected by Griess method in supernatants. The level of cell reactive oxygen species was detected by flow cytometry. The changes of cell mitochondrial membrane potential and apoptosis were observed under fluorescence microscope. The real-time quantitative PCR and Western blotting were used to detect the mRNA and protein expression levels of apoptosis-related genes B-cell lymphoma-2 (Bcl-2) associated X protein (Bax) and Bcl-2, respectively. Results The NO content in the control group, selenium treatment group, SNP treatment group and selenium+SNP treatment group were (10.3 ± 1.8), (9.2 ± 2.1), (15.2 ± 3.5), (14.3 ± 2.6) μmmol/L, respectively; SNP had a main effect on NO content (F=23.33, P < 0.05). The cell reactive oxygen species were 31.63 ± 1.40, 29.52 ± 2.86, 60.62 ± 4.83, 50.08 ± 2.41, respectively; selenium and SNP had main effects on reactive oxygen species(F=12.19, 187.20, P < 0.05), selenium combined with SNP had an interactive effect on reactive oxygen species (F=5.42, P < 0.05). The cell mitochondrial membrane potential levels were 0.42 ± 0.11, 0.37 ± 0.07, 7.25 ± 1.91, and 5.21 ± 1.59, respectively; selenium and SNP had main effects on cell mitochondrial membrane potential levels (F=14.21, 440.01, P < 0.05), selenium combined with SNP had an interactive effect on cell mitochondrial membrane potential levels (F=12.89, P < 0.05). Selenium had main effects on nuclear pyknosis ratio, Bcl-2 mRNA and Bax protein expressions (F=9.52, 10.84, 22.17, P < 0.05); SNP had main effects on nuclear pyknosis ratio, Bax and Bcl-2 mRNA expressions, and Bcl-2 protein expression (F=192.86, 21.90, 16.09, 18.39, P < 0.05); selenium combined with SNP had an interactive effect on Bax, Bcl-2 mRNA and protein expressions (F=20.51, 7.59, 15.38, 11.97, P < 0.05). Conclusion The SNP can induce apoptosis of AC16 cardiomyocyte; selenium combined with SNP has an interactive effect on AC16 cardiomyocyte, indicating that selenium has protective effect on NO modiated myocardial apoptosis. Key words: Nitric oxide; Selenium; Apoptosis