Role of ATP-sensitive potassium channels in inhibitory effect of hydrogen sulfide on high glucose-induced injury in H9c2 cardiac cells / 中国病理生理杂志

AIM:To investigate the roles of ATP-sensitive potassium ( KATP ) channels in high glucose-induced cardiac injury and the inhibitory effect of hydrogen sulfide ( H2 S) on the cardiomyocyte injury.METHODS:The expres-sion level of KATP channel protein was tested by Western blot.The cell viability was measured by CCK-8 assay.The number of apoptotic cells was observed by Hoechst 33258 nuclear staining.Mitochondrial membrane potential ( MMP) was exam-ined by JC-1 staining.RESULTS:After the H9c2 cells were treated with 35 mmol/L glucose ( high glucose, HG) for 1~24 h, the protein level of KATP channel was significantly reduced at 6 h, 9 h, 12 h and 24 h, reaching the minimum level at 12 h and 24 h.Pretreatment of the cells with 400μmol/L NaHS ( a donor of H2 S) prior to exposure to HG for 12 h con-siderably blocked the down-regulation of KATP channels induced by HG.Pretreatment of the cells with 100 μmol/L mito-chondrial KATP channel opener diazoxide, 50μmol/L non-selective KATP channel opener pinacidil or NaHS obviously inhibi-ted HG-induced injuries, leading to an increase in the cell viability, and decreases in the number of apoptotic cells and the MMP loss.Pretreatment with 100μmol/L mitochondrial KATP channel antagonist 5-hydroxydecanoic acid or 1 mmol/L non-selective KATP channel antagonist glibenclamide attenuated the above cardioprotective effects of NaHS.CONCLUSION:KATP channels mediate the inhibitory effect of H2 S on HG-induced cardiac injury.

Angiotensin-(1-7)/Mas receptor axis protects cardiomyocytes against high glucose-induced injury by modulating nuclear factor-κB pathway / 中国病理生理杂志

AIM:Tostudywhe ther theangiotens in-(1-7)[Ang-(1-7)]/Mas receptor axis protects cardio-myocytes against high glucose (HG)-induced injury by inhibiting nuclear factor-κB (NF-κB) pathway.METHODS:The cell viability was measured by CCK-8 assay.The intracellular levels of reactive oxygen species ( ROS) were detected by DCFH-DA staining .The number of apoptotic cells was tested by Hoechst 33258 nuclear staining .Mitochondrial membrane potential ( MMP) was examined by JC-1 staining.The levels of NF-κB p65 subunit and cleaved caspase-3 protein were de-termined by Western blotting.RESULTS: Treatment of H9c2 cardiac cells with 35 mmol/L glucose (HG) for 30, 60, 90, 120 and 150 min significantly enhanced the levels of phosphorated ( p) NF-κB p65, peaking at 60 min.Co-treatment of the cells with 1 μmol/L Ang-(1-7) and HG for 60 min attenuated the up-regulation of p-NF-κB p65 induced by HG. Co-treatment of the cells with Ang-(1-7) at concentrations of 0.1~30μmol/L and HG for 24 h inhibited HG-induced cy-totoxicity, evidenced by an increase in cell viability .On the other hand, 1 μmol/L Ang-(1-7) ameliorated HG-induced apoptosis, oxidative stress and mitochondrial damage , indicated by decreases in the number of apoptotic cells , cleaved caspase-3 level, ROS generation and MMP loss .However, the above cardioprotective effects of Ang-(1-7) were markedly blocked by A-779, an antagonist of Ang-(1-7) receptor (Mas receptor).Similarly, co-treatment of H9c2 cardiac cells with 100 μmol/L PDTC ( an inhibitor of NF-κB) and HG for 24 h also obviously reduced the above injuries induced by HG.CONCLUSION:Ang-(1-7)/Mas receptor axis prevents the cardiomyocytes from the HG-induced injury by inhibiting NF-κB pathway .