ABSTRACT
Objective To verify antioxidation of Au NanoStars/collagen ( AuNSs/Col ) for ventricular myocytes of newborn rats(NRVMs) by in vitro studies.Methods (1)Different concentrations of AuNSs/Col composite materials were created.The optimum concentration of the material was selected by Live /dead staining and Cell Counting Kit-8 (CCK-8) and Col was used for subsequent experiments .( 2 ) NRVMs were randomly divided into Col group , AuNSs/Col group, H2O2-induced Col group, and H2O2-induced AuNSs/Col group.After 6 h treatment, apoptotic cell morphology and early cell apoptosis rate were observed with Annexin Ⅴ-FITC/propidium iodide ( PI)/4′,6-diamidino-2-phenylindole ( DAPI) and the expressions of apoptosis related proteins-B-cell lymphoma-2 ( Bcl-2 ) and Bcl-2 associated x protein ( Bax ) were detected by Western blotting .Results ( 1 ) Both Live/dead and CCK-8 experiments indicated that the AuNSs/Col composite material with 0.1 mg/ml was nontoxicity to NRVMs and could further promote their proliferation .(2) Compared with the uninduced group , the early apoptosis rate of the Col group and the AuNSs /Col group after H2O2 induction was significantly increased , while the Bcl-2/Bax ratio was decreased , indicating that the oxidative stress damage model was established.After H2O2 induction, compared with the Col group , the early apoptosis rate of the AuNSs/Col group was decreased , but the Bcl-2/Bax ratio was increased .Conclusion AuNSs/Col composite material has protective effect on the oxidative damage of cardiomyocytes cultured in vitro.
ABSTRACT
The influences of specific protein phosphatase and protein kinase inhibitors on the ATP-sensitive K+ (KATP) channel-opening effect of pinacidil were investigated in single rat ventricular myocytes using patch clamp technique. In cell-attached patches, pinacidil (100 muM) induced the opening of the KATP channel, which was blocked by the pretreatment with H-7 (100 muM) whereas enhanced by the pretreatment with genistein (30 muM) or tyrphostin A23 (10 muM). In inside-out patches, pinacidil (10 muM) activated the KATP channels in the presence of ATP (0.3 mM) or AMP-PNP (0.3 mM) and in a partial rundown state. The effect of pinacidil (10 muM) was not affected by the pretreatment with protein tyrosine phosphatase 1B (PTP1B, 10 mug ml-1), but blocked by the pretreatment of protein phosphatase 2A (PP2A, 1 U ml-1). In addition, pinacidil (10 muM) could not induce the opening of the reactivated KATP channels in the presence of H-7 (100 muM) but enhanced it in the presence of ATP(1 mM) and genistein (30 muM). These results indicate that the KATP channel-opening effect of pinacidil is not mediated via phosphorylation of KATP channel protein or associated protein, although it still requires the phosphorylation of serine/threonine residues as a prerequisite condition.