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目的探讨聚乙二醇化重组人生长激素(PEG-rhGH)对离体豚鼠乳头肌细胞动作电位的影响,并以重组人生长激素(rhGH)为阳性对照物比较二者的体外生物活性。方法健康雄性DHP豚鼠12只,随机分为2组,PEG-rhGH干预组和rhGH干预组,每组6只。采用累计给药法和给药前后自身对照方法,分别观察不同质量浓度(1、5、10、50、100、500、1 000μg/L)的PEG-rhGH和rhGH对豚鼠乳头肌细胞动作电位的效应,并比较两者效应的大小。以常规玻璃微电极技术记录和测量动作电位各参数,包括静息电位(RP)、动作电位振幅(APA)、动作电位复极50%时程(APD50)和动作电位复极90%时程(APD90)。结果 PEG-rhGH和rhGH对RP、APA均无明显影响(P>0.05),但浓度依赖性延长APD50和APD90,两者差异有显著统计学意义(P<0.01),且APD50延长程度稍大于APD90。相同浓度的PEG-rhGH和rhGH对APD50和APD90的延长程度差异无统计学意义(P>0.05)。结论 PEG-rhGH和rhGH均可延长离体豚鼠乳头肌细胞动作电位时程,以平台期为主,两者效应相近,PEG-rhGH具有与rhGH相似的体外生物活性。
Objective To investigate the effect of pegylated recombinant human growth hormone (PEG-rhGH) on the action potential of guinea pig papillary muscle cells in vitro and to compare the in vitro biological activities of recombinant human growth hormone (rhGH) as a positive control. Methods Twelve healthy male DHP guinea pigs were randomly divided into 2 groups: PEG-rhGH intervention group and rhGH intervention group, 6 rats in each group. Cumulative administration and self-control before and after administration were used to observe the effects of PEG-rhGH and rhGH with different concentrations (1,5,10,50,100,500 and 1,000μg / L) on the action potential of guinea pig papillary muscle cells Effect, and compare the size of both effects. The parameters of action potential were recorded and measured by conventional glass microelectrode technique, including resting potential (RP), action potential amplitude (APA), action potential 50% APD50 and action potential repolarization 90% APD90). Results Both PEG-rhGH and rhGH had no significant effect on RP and APA (P> 0.05), but prolonged APD50 and APD90 in a concentration-dependent manner were significantly different (P <0.01), and APD50 extended slightly more than APD90 . The same concentration of PEG-rhGH and rhGH on the extension of APD50 and APD90 no significant difference (P> 0.05). Conclusion Both PEG-rhGH and rhGH can prolong the action potential duration of guinea pig papillary muscle cells. The plateau phase is the main effect. PEG-rhGH has similar in vitro biological activity as rhGH.