ABSTRACT
AIMTo investigate the effects of prostaglandin E 1 on apoptosis induced by hypoxia/reoxygenation in cultured neonatal rat cardiomyocy tes. METHODSThe models of hypoxia/reoxygenation were made with t he first generation of cultured cardiomyocytes. Hypoxia/reoxygenation apoptosis in cultured neonatal rat cardiomyocytes was studied by agarose gel electrophores is and Tdt-mediated dUTP nick end labeling(TUNEL). Bcl-2 and bax mRNA were det ected by in situ hybridization. RESULTSThe results of DNA electr ophoresis in the H/R group showed the typical DNA ladder. And the DNA ladder decreased gradually corresponding to the increased dose of PGE 1. The TUNEL staining showed that the total number of apo ptotic cells in the H/R group was much biger than that in PGE 1(0 127 ?mol?L -1 ) group. The results of in situ hybridization showed that the conten t of bcl-2 mRNA in H/R group was lower than control. And the content of bax mRN A showed a reverse result as bcl-2 mRNA. Compared with H/R group, the content o f bcl-2 mRNA was significantly higher after treatment with PGE 1(0 014 ?mol ?L -1 , 0 042 ?mol?L -1 , 0 127 ?mol?L -1 ). But the content of bax mRNA in PGE 1(0 014 ?mol?L -1 , 0 042 ?mol?L -1 , 0 127 ?mol?L -1 )groups was significantly lower than H/R group. CONCLUSI ONH/R injury can induce cardiomyocyte apoptosis. PGE 1 has obvious an ti-apoptotic effects on cardiomyocyte and the mechanisms are possibly by inhibi ting the expression of bax and increasing the expression of bcl-2.hein creaseddoseofPGE1 .TheTUNELstainingshowedthatthetotalnumberofapoptoticcellsintheH
ABSTRACT
The effects of sulmazole and isoprenaline on beating rate of cultured neonatal rat ventricular cardiomyocytes were measured with electrooptical technique. The results showed: (1) The spontaneous beating rate of primary cultured cardiomyocytes (culture for 72 h, 37?0.5℃, pH 7.2) was 134?16 beats/min (x?SD, n =41) and remained constant within 120 min. (2) The effect of sulmazole on beating rate was similar to that of isoprenaline. They both produced an apparent positive chronotropic action in a dose - dependent manner within a certain concentration range. The maximal responses between them were not statistical different.