Effects of rehmannia glutinosa polysaccha-rides on myocardial apoptosis of rats after myocardial ischemia-reperfusion injury

Objective To investigate the effects of Rehmannia glutinosa polysaccha-rides (RPS) on myocardial apoptosis of rats after myocardial ischemia-reperfusion injury. Methods The experimental rats were randomly devided into sham operation group, model group, RPS low, medium and high-dose group, Danshen tablets group, 20 rats in each group. All the rats were performed the coronary occlusion operation except the sham operation group. And then, the rats in RPS low, medium and high-dose groups were given RPS 10, 20, 40 mg/kg by intragastric administration; the rats in Danshen tablets group were given Danshen tablets suspension 260 mg/kg; the rats in sham operation group and model group were given the equal volume of saline; once a day for 4 weeks. The areas of myocardial infarction were analysised by TTC staining; the apoptosis of cardiomyocytes was observed by TUNEL and the apoptosis index(AI) were calculated; the expression of bcl-2, Bax, caspase-3 were detected by IHC and were semi-quantitative analysised. Results Compared with the model group, the areas of myocardial infarction (31.7% ± 6.1%, 22.8% ± 5.5% vs. 43.9% ± 6.7%) and the apoptosis index (44.6% ± 6.7%, 32.8% ± 5.4% vs. 59.4% ± 9.0%) in RPS medium and high-dose group (RPS 20, 40 mg/kg) significantly decreased (P<0.05 or P<0.01). The expression of bcl-2 (0.40 ± 0.09, 0.45 ± 0.08 vs. 0.26 ± 0.05) significantly increased (P<0.05 or P<0.01), the expression of Bax (0.55 ± 0.11, 0.28 ± 0.08 vs. 0.85 ± 0.13) and caspase-3 (0.11 ± 0.03, 0.08 ± 0.02 vs. 0.16 ± 0.03) significantly decreased (P<0.05 or P<0.01), and the ratio of bcl-2/Bax (0.73 ± 0.05, 1.61 ± 0.20 vs. 0.31 ± 0.08) significantly increased (P<0.05 or P<0.01). Conclusions RPS had inhibition effects on myocardial apoptosis after myocardial ischemia-reperfusion injury in rats, which may be related to its effects of enhancing the ratio of bcl-2/Bax and down regulating the expression of caspase-3. Key words: Rehmannia glutinosa polysaccharides; Myocardial reperfusion injury; Apoptosis; Rats