Abstract: Objective · To investigate the effect and possible mechanism of silent information regulator 1 (SIRT1) on H2O2-induced oxidative damage in human ovarian granulosa cells. Methods · Human ovarian granulosa cells SVOG were treated with 0, 100, 250, 500, 1 000 μmol/L H2O2 for 4, 8, 12, 24 h, respectively. The cell viability was measured by CCK-8 method, and the appropriate H2O2 concentration and treatment time were used to establish the oxidative stress injury model of granulosa cells in vitro. The nuclear morphological changes after H2O2 treatment were observed with fluorescence microscope. The malondialdehyde (MDA) levels and superoxide dismutase (SOD) activities were detected by chemical chromatometry kits. Real-time quantitative PCR and Western blotting were respectively used to analyze the mRNA and protein levels of SIRT1, P66SHC (the 66 kDa Src homology 2 domain containing isoform) and B-cell lymphoma-2 (BCL-2). The changes of the above indicators were also assessed after SVOG cells were transfected with SIRT1 overexpression plasmid by liposome and treated with H2O2. Results · After treatment with 250 μmol/L H2O2 for 12 h, the SVOG cell viability decreased significantly (P=0.017), the cell nuclei shrank, the MDA level increased (P=0.001), the SOD activity decreased (P=0.006), and the expression of P66SHC increased with the decreased expression of SIRT1 and BCL-2 at mRNA and protein levels. After overexpression of SIRT1 and treatment with H2O2, the nuclei of SVOG cells returned to normal morphology, the MDA level decreased (P=0.038), the SOD activity increased (P=0.021), the expression of P66SHC decreased (P=0.002) and the expression of BCL-2 increased (P=0.013). Conclusion · SIRT1 can protect human ovarian granulosa cells from oxidative damage by down-regulating the expression of P66SHC and up-regulating BCL-2.

Key words: ovarian granulosa cell, silent information regulator 1 (SIRT1), oxidative damage, the 66 kDa Src homology 2 domain containing isoform (P66SHC), B-cell lymphoma-2 (BCL-2)