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.

Objective To study the relationship between serum uric acid and insulin resistance in type 2 diabetic patients Methods A total of 728 middle-aged and elderly type 2 diabetic patients were recruited and the anthropometric,clinical and biochemical parameters and fasting serum C-peptide were measured and retrospectively studied.All patients were divided into groups based on the levels of uric acid and on metabolic syndrome diagnosis or not.Results Among a total of 728 patients,the proportion of hyperuricemia was 26.9％(196/728),and metabolic syndrome(MS)was 64.6％.The levels of body mass index(BMI),waist circumference(WC),systolic pressure (SBP),diastolic pressure (DBP),triglyceride (TG),fasting C-peptide,HOMA(C-Peptide) were significantly higher in hyperuricemia group than in normal uric acid group,while the level of HDL was lower in hyperuricemia group than in normal uric acid group.The proportion of MS was statistically higher in hyperuricemia group (81.6％)than in normal uric acid group (58.3％,P ＜ 0.05).Groups Ⅰ,Ⅱ,Ⅲ,Ⅳ-the four quartiles of serum uric acid from low-to high-level were correlated with MS component number of 2.1±1.0,3.1±1.1,3.3±1.2,3.7±0.8,separately,and with HOMA(CP)of 3.7± 0.8,3.7 ± 0.8,4.0 ± 0.6,4.1 ± 0.9,separately (all P ＜ 0.05).When all patients were divided into groups based on with or without MS,the level of uric acid in MS group was (377.3 ± 43.5)μumol/L,and the proportion of hyperuricemia was 34.0％ (160/470),and HOMA(CP)was 3.90±0.72,all were significantly higher than those of non-MS group[(318.2±47.9)μmol/L,14.0％ (36/258),3.64±0.67].The levels of serum uric acid in groups with 1-5 components of MS were(285.0±62.8)μmol/L,(335.7±62.7)μmol/L,(367.1±45.0) μmol/L,(377.9±40.2) μmol/L,(389.8±46.6)μmol/L,and HOMA(CP) was 3.6±0.6,3.7±0.7,3.9±0.8,3.9±0.7,4.3±0.7 separately(P＜0.05).Serum uric acid was positively correlated with age,WC,BMI,TG,SBP,fasting C-peptide,and HOMA (CP),while negatively correlated with glycosylated hemoglobin(HbA1C),high density lipoprotein cholesterol (HDL-C).Binary logistic regression showed that the OR value of MS was 1.033 with the increase of serum uric acid,and 95％CI:1.026-1.041,P＜0.05.Conclusions Serum uric acid is correlated with insulin resistance in middle-aged and elderly hospitalized patients with type 2 diabetes.Hyperuricemia might be a new risk factor for MS.

The impact of hypofunction of kidney on evaluating of islets β cell function in patients with type 2 diabetes was investigated. 635 type 2 diabetic patients with normal liver function were grouped using Cockcroft-Gault. Following the decrease in kidney function, blood C-peptide concentration was increased with decreased urinary exeretion of C-peptide(P<0. 05). It is proposed to pay an attention to renal function while evaluating islets β cell function in the patients.