Baicalin Mediates PI3K/AKT Pathway to Reduce the Apoptosis and Inflammation of Cardiomyocytes Induced by Lipopolysaccharide
JIN Yijing1, LI Kandong1, ZHAN Zhihui1, WANG Yong2*
The aim of this study was to explore the regulatory effects of baicalin on apoptosis, inflammation and PI3K (phosphatidylinositol 3-kinase)/AKT (protein kinase B) signaling pathway induced by LPS (lipopolysaccharide) in rat cardiomyocytes. Rat myocardial H9C2 cells were cultured in vitro. They were divided into control group (no intervention), LPS group (10 μg/mL LPS), experimental group (10 μg/mL LPS+10, 20, 40, 80 μmol/L baicalin) and baicalin+Y group (10 μg/mL LPS+10 μmol/L baicalin+5 μmol/L PI3K/AKT pathway inhibitor LY294002), inhibitor group (10 μg/mL LPS+5 μmol/L LY294002) and baicalin+A group [10 μg/mL LPS+10 μmol/L baicalin+100 ng/mL PI3K/AKT pathway activator IGF-I (insulin-like growth factor-I)]. Cell viability was measured with cell counting kit8; the levels of IL-1β (interleukin-1β), IL-6 and IL-10 were examined with enzyme-linked immunosorbent assay; the apoptosis rate was determined by Hoechst33258 staining; cell proliferation rate was determined by 5-ethynyl-2’-deoxyuridine; the expression levels of PI3K/AKT-related protein, CyclinD1 protein and Caspase-3 protein were determined by WB (Western blot). The results showed that cell viability in LPS group was significantly lower than that in control group (P<0.05), the cell viability of 10 μg/mL LPS+10 μmol/L baicalin group was significantly increased compared with LPS group (P<0.05), so 10 μmol/L baicalin was selected for follow-up experiment. The content of Il-10, the rate of cell proliferation and the expression of CyclinD1 protein in LPS group were significantly lower than those in control group (P<0.05), the contents of IL-6 and IL-1β, the rate of apoptosis, the expression of Caspase-3, p-PI3K and p-AKT proteins were significantly higher than those in the control group (P<0.05); the change trend of the above indexes in H9C2 cells of baicalin group (10 μg/mL LPS+10 μmol/L baicalin group) and inhibitor group was significantly reversed compared with those in LPS group (P<0.05); IL-10 content, cell proliferation rate and CyclinD1 protein expression level of baicalin+Y group were significantly increased compared with baicalin group (P<0.05), the contents of IL-6 and IL-1β, apoptosis rate, and the protein levels of Caspase-3, p-PI3K and AKT were obviously lowered (P<0.05); the change of indexes in baicalin+A group was opposite to that in baicalin+Y group (P<0.05). In conclusion, baicalin can inhibit LPS-induced apoptosis and inflammation of H9C2 cells by blocking PI3K/AKT signal transduction.
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