黄芪提取物对大鼠心肌梗死后心肌组织PKD1蛋白表达的影响

目的探讨黄芪提取物对大鼠心肌梗死后心肌组织蛋白激酶D1(PKD1)蛋白表达的影响。方法成功构建大鼠心肌梗死模型后,随机分为模型组、黄芪提取物3个不同剂量组,每组8只大鼠,另设假手术组8只。术后48 h,黄芪提取物组分别给予低、中、高10,20,40 mg.(kg.d)-1灌胃;模型组和假手术组给予生理盐水20 ml.(kg.d)-1灌胃。8周后测定大鼠的血流动力学变化;应用HE染色分析左心室心肌细胞组织形态学变化;采用Masson染色法检测左心室心肌胶原纤维变化;应用免疫组化法和免疫印迹法分析左心室心肌组织PKD1蛋白的表达情况。结果血流动力学检测结果表明,和模型组相比,假手术组、各治疗组心脏左室收缩压(LVSP)、左室内压曲线最大上升和下降速率(±dp/dt)均明显升高(P<0.05),左室舒张末压(LVEDP)均明显降低(P<0.05)。HE染色分析,模型组大鼠心肌细胞坏死严重,成纤维细胞增生明显,伴有炎症细胞浸润;黄芪提取物低、中剂量组大鼠心肌细胞淡染,界限欠清晰,部分细胞核肥大,伴有成纤维细胞增生和少量炎症细胞浸润;高剂量组大鼠心肌细胞形态较清晰,成纤维细胞和炎症细胞少见。Masson染色表明,模型组大鼠心肌以胶原组织为主,各治疗组大鼠以红色心肌组织为主,间杂以胶原组织。免疫组化和免疫印迹分析表明,模型组大鼠心肌组织胞质中PKD1蛋白的表达明显;和模型组相比,各治疗组大鼠心肌细胞胞质中PKD1蛋白的表达明显下调(P<0.05),但仍清晰可见。结论黄芪提取物可明显改善大鼠心肌梗死后异常的血液流变学指标、组织病变及胶原纤维构成比例,其作用机制可能与下调心肌组织PKD1蛋白的表达相关。

Effect of astragalus extract on the levels of PKD1 protein in rats with myocardial infarction

Aim To study the effect of astragalus extract on the levels of PKD1 protein in rats with myocardial infarction(MI).Methods Left coronary artery of Sprague-Dawley(SD) rats were ligated to make MI models.The rats were randomly subjected to MI model group,sham-operated group,and three different astragalus extract(AE)(10,20,40 mg·kg-1·d-1) groups,each group consisted of 8 rats.The MI group and sham-operated group were fed 0.9% sodium chloride 20 ml·kg-1·d-1.8 weeks later,the rats were sacrificed,the hemodynamic changes in rats were determined,and the segmental heart samples were used for hematoxylin and eosin staining,masson staining and histological evaluation on expression of protein kinase D1(PKD1).Immunoblotting analysis was also employed to determine alterations in protein levels of PKD1.Results Compared with the MI group,the left ventricular systolic pressure(LVSP) and maximal decrease and increase rate of pressure in left ventricle of all the AE groups,and sham-operated group increased significantly(P<0.05),while the left ventricular end diastolic pressure(LVEDP) decreased significantly(P<0.05).There were serious myocardial necrosis,fibroblasts increasing,accompanied by inflammatory cell infiltration in the rats of MI group,and slightly fuzzy cell morphology,nuclear hypertrophy,mild proliferation of fibroblasts,inflammatory cells decreasing in the AE(10,20 mg·kg-1·d-1) groups,while more clear cell morphology,rare fibroblasts and inflammatory cells in the AE(40 mg·kg-1·d-1) group,according to the HE staining analysis.The masson staining results showed that the MI group consisted of more myocardial collagen tissue,yet all the AE groups consisted of mainly red myocardial tissue,intermingled collagen tissue.The PKD1 protein expression in the cytoplasm of myocardial tissue of all the AE groups decreased significantly(P<0.05)by histological evaluation,compared with the MI group.And the immunoblotting analysis achieved the same results.Conclusion Our study reveals that the astragalus extract can significantly ameliorate the abnormal hemorheological indicators,pathologic lesions,and component proportion ratio of collagen fibers,which is probably related to the down-regulation of the expression of PKD1 protein in rats with myocardial infarction.