三七总皂苷抗大鼠心肌肥大的作用及其神经机制

目的　探讨三七总皂苷 (PNS)抗腹主动脉缩窄大鼠压力超负荷性心肌肥大的神经机制。方法　①用腹主动脉缩窄法建立心肌肥大模型 ,将大鼠分为假手术对照组、腹主动脉缩窄组及低、中、高剂量组 ,3个剂量组分别每日腹腔注射5 0、10 0和 15 0mgPNS·kg-1。 3wk后处死大鼠检测全心重量/体重 (HW/BW )、左室重量指数 (LVI) ,左心室组织切片HE染色后测心肌纤维直径 (MD)。②细胞内生物电记录技术观察PNS对大鼠星状神经节 (SG)的快兴奋性突触后电位 (f EPSP)、膜电位、膜电阻及对外源性乙酰胆碱引起的膜除极化反应的影响。结果　①高剂量组的HW /BW、LVI及MD显著低于缩窄组 ,P <0 0 1;中剂量组与缩窄组比较MD显著降低 ,P <0 0 5 ;低剂量组与缩窄组比较 ,HW/BW ,LVI和MD三项指标均无显著的变化。②PNS在 0 10～ 0 16g·L-1浓度范围内可使大鼠星状神经节f EPSP可逆性减小 ,PNS还可拮抗高钙对f EPSP的易化作用 ,但对膜电位、膜电阻及外源性ACh引起的膜除极反应无显著的影响。结论　PNS对f EPSP的抑制可能是其抗压力超负荷性心肌肥大的神经机制 ,而抑制作用则是通过突触前机制产生 ,且与拮抗Ca2 + 内流有关。

The inhibitory effects of PNS on cardiac hypertrophy and its nervous mechanism

Aim To investigate the antagonistic action o f total saponins of panaxnotoginseng(PNS) on cardiac hypertrophy and its nervous mechanism.Methods (1)cardiac hypertrophy of rats due to pressure overload was induced by constricting of abdominal aorta. There were five groups in the experiments. The rats in Group A(control group)were sham operated . Group B was aorta-constricted group.The rats in Group C,D,E were given ip PNS 50,100,150 mg·kg·d -1 for three weeks respectively. Three weeks later, We measured the heart-weight(HW),left ventricular weight(LVW), the ratio of HW/BW,LVW/BW (LVI) and the cardiomyocyte diameters(MD) after dyeing by HE color.(2)The effects of PNS on the fast excitatory postsynaptic potential(f-EPSP),membrane depolarization induced by application of acetylcholine (ACh),membrane potential and membrane resistance of the isolated Stellate ganglion(SG)of the rats were investigated by means of intracellular recording techniques. Results (1)HW/BW, LVI and MD of Group E were significantly lower than that of Group B(P<0.01).MD of Group D was also significantly lower than Group B (P<0.05).But HW/BW,LVI of Group D and HW/BW, LVI and MD of Group C were not significantly changed (P>0.05).(2)At the concentration of 0.10 ～0.16 g·L -1, PNS reversibly depressed the amplitude of f-EPSP, but the ACh depolarization,membrane potential and membrane resistance were not significantly altered by PNS. Conclusion PNS can prevent cardiac hypertrophy due to pressure overload in rats and this action may underline its inhibitory action on presyn aptic effect of regulating calcium influx.