【摘要】 目的探讨慢性心衰时豚鼠心肌细胞收缩及钙瞬变的变化。方法以降主动脉缩窄法及异丙肾上腺素(isoproterenol,ISO)法建立豚鼠慢性心衰模型成功后,以酶解法急性分离左室心肌细胞,然后同步检测两种心衰时心肌细胞收缩和钙瞬变的变化。结果降主动脉缩窄8周后,70%豚鼠出现呼吸困难(BPC组),而给予ISO 8周后的豚鼠(ISO组)未见明显呼吸困难,BPC组及ISO组豚鼠的左室收缩压及舒张末压显著增高,左室压上升和下降最大速率显著降低;左心室质量与体质量比值、肺质量与体质量比值及室壁厚度明显增高,均呈现明显的心衰特点。而缩窄8周后未见呼吸困难的豚鼠(BWPC组)仅左心室质量与体质量比值增加,心脏功能尚处于代偿期。两种心衰心肌细胞收缩幅度、收缩和舒张速度均明显减弱,且BPC组收缩幅度、舒张速度比ISO组减弱更明显;BWPC组的心肌细胞收缩幅度、收缩和舒张速度却明显增高。BPC组心肌细胞内舒张期钙升高,钙瞬变幅度减小,舒张期钙减少50%所需时间(T50DCa)延长;而BW-PC组心肌细胞内钙无明显变化;ISO组心肌细胞内舒张期钙和收缩期钙均降低,钙瞬变幅度也减小,T50DCa却无明显改变。结论降主动脉缩窄或给予ISO 8周后,均可造成豚鼠心衰。心衰后心肌细胞收缩功能减弱,钙瞬变幅度减小。更多还原

【Abstract】 Objective To explore the changes of myocyte contraction and calcium transient in heart failure models.Methods Chronic heart failure（CHF） was inflicted in guinea pigs by constricting descent aorta（n=22） or injecting isoproterenol（ISO,n=18） for 8 weeks.Animals without constriction or getting normal saline injection served as their controls.After the left ventricular myocytes were enzymatically isolated from both normal and failed hearts,the contractile and calcium transient of a single myocyte were assessed simultaneously.Results Of 70% animals receiving the constriction developed dyspnea（BPC group）,but ISO-injected pigs had no this symptom（ISO group）.These animals all showed the symptoms of CHF,including increased left ventricular systolic and diastolic pressures,decreased maximal velocities of left ventricular pressure rising and falling,elevated mass ratios of ventricle to body and lung to body,and the increase of left ventricular hypertrophy.In the animals showing no dyspnea after 8 weeks’ constriction（BWPC group）,there was only increased mass ratio of ventricle to body,indicating in the course of compensation.Compared with normal cells,the extent of contraction,the velocities of myocyte contractile and diastole were decreased significantly in BPC and ISO groups,with the former more obvious than the later,but these items in BWPC group were significantly increased.In myocytes from BPC group,the diastolic calcium was increased,the calcium transient was decreased,and the time to 50% diastolic calcium(T₅₀DCa)was delayed.But no change was observed in these indexes in BWPC group.In ISO group,the systolic and diastolic calcium,and calcium transient were decreased,and T₅₀DCa remained in its origin.Conclusion Constricting descent aorta or injecting ISO for 8 weeks both can inflict CHF in guinea pig.Cell contraction and calcium transient are decreased in a single ventricular myocyte after CHF establishment.更多还原