大豆异黄酮对糖尿病大鼠心肌收缩性的影响

Influence of soy isoflavones on myocardial contractility of diabetic rats

目的探讨大豆异黄酮(soyisoflavones,SI)对糖尿病大鼠心肌收缩性的影响。方法SD大鼠48只,随机分为正常对照组(NC)、糖尿病对照组(DC)、低剂量SI治疗组(LSI)、中剂量SI治疗组(MSI)、高剂量SI治疗组(HSI)、尼尔雌醇治疗组(NT)。后5组腹腔注射链脲佐菌素55mg/kg制备DM模型。第7周起,NC、DC组予0.5%CMCNa10ml/(kg·d),LSI、MSI、HSI组分别予大豆异黄酮30、60、120mg/(kg·d),NI组予尼尔雌醇混悬液0.1mg/kg(2次/周)灌胃,以上以体重计,第12周末采集心室内压并分析。电镜观察心肌细胞超微结构改变。结果大鼠左室收缩压、左室发展压、平均压、室内压最大上升/下降速率、室内压上升达最大速率所需时间和心肌纤维最大缩短速度等心功能指标,DC组明显低于NC组(P<0.01);MSI、HSI组、NT组均明显高于DC组(P<0.05,P<0.01)。心肌细胞超微结构:DC组肌小节失去正常结构,肌原纤维坏死、溶解;线粒体水肿,嵴消失。中、高剂量SI可明显逆转上述改变。结论中、高剂量SI可提高糖尿病鼠左心室功能,减轻心肌超微结构损伤。

Objective To investigate the influence of soy isoflav ones on myocardial contractility of diabetic rats. Methods 48 S D rats were randomly divided into 6 groups: normal control group (NC), diabetic control group (DC), 3 SI treatment groups(L-SI,M-SI,H-SI) and nilestrioli treatment group (NT). Rats were given streptozotocin (STZ) 55 mg/ kg intraperitneally (ip) except NC group rats. After 6 weeks, SI 30, 60, 120 mg/ (kg·d) were given in L-SI, M-SI, H-SI groups, nilestriol 0.2 mg/(kg·wk) was given in NT group,and the same CMC-Na was given in NC and DC groups. The vol umes in all groups were 2 ml/(kg·d). The drugs were all oral administe red using a stomach (tube.) ①LVSP(left ventricular systolic (pressure),)LVDP ((l eft) ventri cular developed pressure), Mean, ±dP/dt_(max), Vpm and t-dP/dt of ra ts were recorded, observed and analyzed. ②The ultrastructure of heart cells was investigated with eletronmicroscopy. Results Compared with NC group, Peak,LVSP,LVDP,Mean,±dP/dt_(max),Vpm and t-dP/dt of DC group were significantly lower(P<0.05, P<0.01), but those of SI groups were markedly hig her than those of DC group(P<0.01). ②Electron microscopic observation of m yocardial muscle in DC groups revealed typical alterations consisting of an increase in collagen content, diminishing of the cardiomyocyte diameter, alteration in myofilaments and Z-lines of and myofibrillary degeneration. The above changes were inhib ited by SI 60,120 mg/kg. Conclusion M-SI, H-SI treatments could improve contractivities of heart-failure diabetic rats and prevent myocyte diameter. Degenerations in myofilaments were reversed by SI.