Beneficial effects of silymarin against nitric oxide-induced oxidative stress on cell characteristics of bovine oviduct epithelial cell and developmental ability of bovine IVF embryos

Abstract

The antioxidative effects of silymarin were examined against nitric oxide-induced oxidative stress on cell characteristics of bovine oviduct epithelial cell (BOEC) and developmental rates of bovine in vitro fertilisation (IVF) embryos. The cell viability and morphology in BOEC which were treated with sodium nitroprusside (SNP) declined, as concentrations of SNP increase. The additions of silymarin 50, 100 and 200 µM into SNP 1000 µM increased the cell viability inhibited by SNP 1000 µM alone, but addition of silymarin 500 µM into SNP 1000 µM group did not recover the inhibitory effect of SNP 1000 µM (p<0.05). The levels of malondialdehyde (MDA), as the indicator of lipid peroxidation (LPO) in the treatments of SNPs increased with dose-dependant manners (p<0.05), whereas additions of silymarin 50, 100 and 200 µM into SNP 1000 µM significantly decreased MDA levels by 1.6, 1.4 and 1.3 folds of control (p<0.05). Antioxidant and Bcl-2 genes were expressed in control or SNP 1000 µM plus silymarin 200 µM treatment group, whereas pro-apoptotic genes (caspase-3 and Bax) were expressed only in SNP treatment groups. When bovine IVF embryos were co-cultured with BOEC supplemented with silymarin in the presence or absence of SNP, the development ability to blastocyst in 200 µM of silymarin alone was the highest among all treatments. These results suggest that silymarin has positive effects on cell characteristics such as viability, morphology and LPO of BOEC, and the increase of bovine IVF embryo development rate might be through antioxidative and anti-apoptotic actions.