Fig. 6. GS increase mitochondrial function against the hypoxia- and OGD-induced injuries of the cardiomyocytes through the activation of SIRT1. (A) H9c2 cells were pretreated with GS for 48 h and kept in the medium with 800 μM CoCl2 (hypoxia) or serum and glucose-free and 800 μM CoCl2 (OGD) for 9 h. Cell viability was analyzed by the CCK8 assay kit and showed as the percentages. (B-C) Basal OCR and ATP content were measured in H9c2 cells, after GS pretreatment for 48 h and hypoxia/OGD incubation for 9 h. (D) H9c2 cells treated with GS for 48 h and incubated with hypoxia exposure for 9 h were collected and lysed to analyze the levels of complex I-V by Western blot. (E) Relative levels of CV-ATP5A, CIII-UQCRC2, CIV-MTCO1, CII-SDHB, and CI-NDUFB8 from (D) were calculated by Image J. (F) After GS treatment for 48 h, the expressions of SIRT1 and PGC-1α in H9c2 cells subjected to hypoxia and OGD injury were examined by Western blot. (G) Bar graphs show relative levels of SIRT1 and PGC-1α from (F). β-Actin is loading control. Ctrl: control group, CoCl2: cobalt chloride. *P < 0.05, **P < 0.01, and ***P< 0.001 versus Ctrl group; #P< 0.05 and ##P < 0.01versus hypoxia or OGD group.