Role of oxidative stress in diabetic cardiomyopathy of rats / 中国医师杂志

ABSTRACT

Objective To investigate changes of oxidative stress in the hearts and their roles in diabetic cardiomyopathy of rats.Methods Thirty six rats with diabetic cardiomyopathy were induced by streptozocin(STZ),and were randomly divided into three groups:(1) normal control (NC) group,normal control rats; (2) Diabetes maintain (DM) group,diabetic rats received protamine zinc insulin (PZI) 2 ～4 U/2 days; and (3) Diabetes treatment (DT) group,diabetic rats received PZI 9 ～ 12 U/kg body weigh/day.After 12 weeks,rats were killed,and the parameters including blood glucose,glycated hemoglobin a1c (HbA1c),total cholesterol (TC),and triglyceride (TG) were measured.Maleic dialdehyde (MDA),the total antioxidant capacity of the hearts,and activities of antioxidant enzymes in hearts including total superoxide dismutase (TSOD),catalase (CAT),and glutathione peroxidase (GSH-Px) were measured by chromatometry.The pathologic changes of heart tissues were studied by hematoxylin eosin (HE),periodic acid Schiff (PAS),and nitrotyrosine (NT) staining.Results After 12 weeks,parameters including blood glucose,HbA1c,TC,and TG were increased significantly in DM group relative to NC group or DT group.The level of heart MDA was elevated obviously in the DM group [NC group (7.82 ±0.62) nmol/mgprot,DM group (12.81 ± 1.35) nmol/mgprot,and DT group (8.20 ±0.85) nmol/mgprot].The total antioxidant capacity and activities of TSOD [(235.09 ± 14.94) U/mgprot],GSH-Px [(56.59 ± 4.96) U] were decreased significantly in the DM group.The level of CAT [(13.84 ± 2.88) U/mgprot] was increased obviously in the DM group.The cardial myocyte hypertrophy,myocyte steatosis,and PAS positive material could be found in the hearts of rats in DM group with HE and PAS staining.The expression of NT was much stronger in DM group than NC or DT groups.NT was less expressed in DT group,and was almost not expressed in the NC group.Conclusions Oxidative stress could be caused by diabetes in diaetic hearts and might play an important role in the etiology of diabetic cardiomyopathy.