| Objective:After various treatments for diabetic rats,which were induced by streptozotocin,the changes in myocardial structure and function and expression of autophagy-related proteins were evaluated to further verify the protective effect of Astragalus polysaccharides on cardiomyocytes in diabetic cardiomyopathy rats,and further explore whether to mediate the regulation through the autophagy pathway,so as to improve the relevant pharmacological mechanisms of Astragalus polysaccharide in the intervention of diabetic cardiomyopathy.Methods:Healthy SPF male SD rats?n=30?were randomly assigned into normal control group?NC group?,diabetic cardiomyopathy group?DCM group?and treatment of Astragalus polysaccharide group?APS group?.The rats of the latter two groups were treated with a single dose of 50 mg·kg-1 streptozotocin so as to establish diabetic rat models.The three groups were given an equal volume of normal saline,normal saline,and Astragalus polysaccharide solution(1 g·kg-1·d-1)for 16 weeks,respectively.The rats were kept with food and water accessible ad libitum.The weight and blood glucose of rats were monitored regularly every week.Later,transthoracic echocardiography assessed left ventricular end-systolic diameter?LVESD?,left ventricular end-diastolic volume?LVEDV?,left ventricular end-diastolic diameter?LVEDD?,left ventricular end-systolic volume?LVESV?,ejection fraction?EF?,and fractional shortening?FS?in order to evaluate changes in cardiac function of rats;HE staining was used to observe myocardial histomorphological changes;TUNEL staining was used to detect myocardial apoptosis;Western blot was used to detect the expression levels of autophagy-related proteins,such as p62 and LC3.Statistical analysis of data was performed using SPSS 24.0 software.All measurement data were expressed as?±.Image J software was used for optical density analysis.One-way or two-way ANOVA was used for comparison between multiple groups.The SNK-q test was used for multiple comparisons.Statistical results of P<0.05 indicated that the differences were statistically significant.Results:?1?Evaluation of general condition of animal models:Due to the induction of streptozotocin,rats in the DCM group and the APS group immediately developed diabetes symptoms such as polydipsia,polyuria,and polydipsia.Compared to the NC group,the rats in the DCM group showed a decrease in body weight and a significant increase in blood glucose?P<0.05?.After 16 weeks of APS intervention,compared to the DCM group,the symptoms of polydipsia,polyuria,and polydipsia of the rats in the APS group were alleviated with weight gain increased,and blood glucose decreased?P<0.05?.?2?Changes of rats'cardiac function:Compared to the NC group,the LVESV,LVEDD,LVEDV,and LVESD of the DCM group increased,and the EF and FS decreased?P<0.05?.The APS intervention significantly reduced the former four indicators,with EF and FS increased?P<0.05?.?3?Changes in the structure of myocardial tissue:The results of the NC group showed that the cardiomyocytes were intact,with muscle fibers well arranged,and there was no apoptosis cells and inflammatory cells infiltration.The results of the DCM group changed abnormally,with cardiomyocytes hypertrophy,disordered arrangement,muscle fiber breakage,unclear cell borders,and different cell sizes.After APS intervention,the myocardial tissue was arranged more neatly than the DCM group,and apoptosis cardiomyocytes decreased with lighter inflammation.?4?The results of TUNEL staining:Compared to the NC group,the cardiomyocyte apoptosis increased in the DCM group?P<0.05?;after APS intervention,the cardiomyocyte apoptosis rate decreased?P<0.05?;?5?Western blot to evaluate changes in autophagic protein expression:Compared to the NC group,the expression of LC3-?/?decreased and the expression of p62 increased in the DCM group?P<0.05?;compared to the DCM group,the expression of LC3-?/?increased and the expression of p62 decreased after 16 weeks of APS intervention?P<0.05?.Conclusion:?1?Astragalus polysaccharide can mitigate myocardial pathological changes and may improve cardiac function in diabetic cardiomyopathy rats.?2?Astragalus polysaccharide can reduce cardiomyocyte apoptosis in rats of diabetic cardiomyopathy,which may be related to its activation of autophagy. |
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