异丙肾上腺素对去势雌性大鼠心脏功能的影响

目的探讨不同剂量异丙肾上腺素(ISO)对双侧卵巢切除大鼠心脏功能的影响。方法健康雌性SD大鼠90只,随机分为对照组、假手术组和双侧卵巢切除组(切除组),每组30只。术后4周3组大鼠进行心脏体外灌流,酶法分离得单个心肌细胞。分别测定各组单个心肌细胞基本收缩幅度和不同浓度ISO刺激心肌细胞收缩幅度;ISO 5 mg/(kg·d)腹腔注射28 d后,测定各组大鼠存活率。结果与对照组和假手术组比较,切除组大鼠心肌细胞基本收缩幅度和不同浓度ISO刺激心肌细胞收缩幅度均显著升高,且呈浓度依赖性升高(P0.05);切除组大鼠心肌细胞的存活率下降,大鼠28 d的存活率明显降低,差异有统计学意义(P0.05)。假手术组上述指标与对照组比较,差异无统计学意义(P0.05)。结论不同剂量ISO对双侧卵巢切除大鼠心脏功能的影响不同。双侧卵巢切除大鼠心脏抗ISO损伤能力减弱。

Effects of isoproterenol on cardiac function of ovariectomized rats

Objective To investigate the effects of different doses of isoproterenol(ISO) on cardiac function of ovariectomized rats.Methods Ninety healthy female SD rats were randomly divided into normal control group (Control),sham operation group (Sham) and bilateral ovariectomy group(Ovx).Four weeks after the operation,the rat hearts were quickly removed,mounted on Langendorff apparatus and perfused with Krebs-Henseleit solution.Hemodynamic parameters were measured.Then,cardiomyocytes from these hearts were isolated and resuspended in Krebs-Bicaronate buffer.The cardiomyocyte contraction amplitude was evaluated including basal and ISO-stimulated contraction.The cardiomyocyte viability was measured after it was incubated with 5000 nmol/L ISO for 2 hours.Mortality of the rats was examined after chronic treatment with ISO 5 mg/(kg·d) for 28 days.Results Compared with control group,Ovx promoted body weight gain,reduced serum estrogen and uterine weight,had no effects on hemodynamic parameters, increased both basal and ISO-stimulated contraction,decreased the viability of cardiomyocytes, increased mortality of the rats.ISO increased the cardiomyocyte contraction amplitude in a concentration-dependent manner and 100 nmol/L of the drug exerted a maximal effect.ISO-elicited changes in contraction were more significant than the basal contraction in every group.There was no significant difference in above indexes between Control and Sham groups.Conclusion The effects of different doses of ISO on cardiac function were different in ovariectomized rats.The ability of ovariectomized rat hearts to resist against injury induced by ISO was weakened.