Improvement Effect and Its Mechanism of Active Components of Averrhoa carambola on High Glucose-induced Injury of H 9c2 Myocardial Cell / 中国药房

OBJECTIVE：To study the imp rovement effects of 2-dodecyl-6-methoxycyclohexa-2，5-diene-1，4-dione（DMDD） from Averrhoa carambola on H 9c2 myocardial cell injury induced by high glucose and its mechanism. METHODS ：H9c2 myocardial cells were divided into normal group ，high glucose group ，osmotic pressure control group ，DMDD high ，medium and low concentration groups （8，4，2 μmol/L）. Normal group and high glucose group were treated with low glucose DMEM medium （containing 5.5 mmol/L glucose ，similarly hereinafter ） and high glucose DMEM medium （containing 33.3 mmol/L glucose ， similarly hereinafter ）for 48 h，respectively. The cells in osmotic pressure control group were cultured in low glucose DMEM medium containing 27.5 mmol/L mannitol for 48 h. In DMDD groups ，cells were cultured in high glucose DMEM medium for 24 h， and then in high glucose DMEM medium containing corresponding concentration of DMDD for 24 h. At the end of cell culture ，MTT metho d was used to detect the cell survival rate. The activities of ROS ， GSH-Px and LDH in cellsupernatant were detected by using related kits. ELISA assay was used to detect the levels of TNF-α and IL-6 in cell supernatant. Cell apoptosis was d etected by acridine orange/ethidium bromide （AO/EB）staining. Western blot assay was used to detect the expression of apoptosis related proteins （cleaved caspase- 3，Bcl-2，Bax）and the phosphorylation level of nuclear factor κB （NF-κB）/NF-κB suppressor protein α（IκBα）signaling pathway related proteins （NF-κB p65，IκBα）. RESULTS ：Compared with the normal group ，survival rate ，the activity of GSH-Px and protein expression of Bcl- 2 in high glucose groups were decreased significantly（P＜0.01）；the activities of ROS and LDH ，the levels of TNF-α and IL-6，the protein expression of Bax and cleaved caspase-3，and the phosphorylation level of NF-κB p65 and IκBα were increased significantly（P＜0.01）；the cells showed orange yellow fluorescence ，and the number of cells with fuzzy morphology increased significantly ，showing an obvious apoptotic state. There was no statistical significance in above indexes of osmotic pressure control group compared with normal group. Compared with high glucose group ，the activities or levels of above indexes （except for cell survival rate an LDH activity in low concentration group ）were reversed significantly in DMDD groups （P＜0.05 or P＜0.01）；the orange yellow fluorescence in the cells decreased significantly ，and the cell morphology was relatively complete. CONCLUSIONS ：DMDD can significantly improve H9c2 myocardial cell injury induced by high glucose ；the mechanism of which may be associated with suppressing oxidative stress and inflammatory response ，regulating the expression of apoptosis related protein and NF-κB/IκBα pathway related protein.

The role of miR-221 in the injury induced by hydrogen peroxide in rat myocardial cells / 中国比较医学杂志

Objective To explore the role of miR-221 in the injury induced by hydrogen peroxide (H2O2) in rat myocardial cells (H9c2).Methods The viability of H9c2 cell induced by cell different concentrations of H2O2 was determined by MTT.The expression of miR-221 was detected by RT-PCR method.The miR-221 inhibitor and negative control were transferred into H9c2 cells by Lipofectamine 2000, then the cells were divided into normal control group, model control group (H2O2 group), negative control group (H2O2+ negative control group), inhibition group (H2O2+miR-221 inhibitor group).The cell viability was measured by MTT assay.Cell apoptosis was detected by acridine orange staining method.The expression of Bcl-2, Bax, phosphatase and tensin homolog deleted on chromosome ten (PTEN, p-protein kinase B (AKT) were assayed by Western Blot.Results 0,25,50,100,200,400 μmol/L H2O2 inhibited H9c2 cell activity gradually, of which 200 mol/L inhibition of cell viability moderate, so as a subsequent induction dose.Compared with normal control group, cell viability was decreased (P < 0.01), cell apoptotic rat was increased (P < 0.01), the expression of Bax and PTEN was upregulated (P < 0.01), the expression of Bcl-2 and p-AKT was downregulated (P < 0.01) in model control group and negative control group.Compared with model control group and negative control group, inhibition group proves the contrary.Conclusions Down-expression of miR-221 could significantly inhibit oxidative stress damage in H9c2 cells, which related to regulation of PTEN/AKT signal pathway.