[Improvement of the function of islet beta and alpha cells by intervention against glucotoxicity: experiment with rats].

OBJECTIVE: To investigate the effects of intervention against glucotoxicity on improvement of the function and pathological changes of islet beta and alpha cells. METHODS: Thirty-six male Sprague Dawley rats were randomly divided into four equal groups: normal control (NC) group, fed with standard chow, high-fat (HF) group, fed with extra high-fat chow; diabetes mellitus (DM) control group, fed with high-fat chow for 8 weeks followed by 30 mg/kg streptozotocin injection to establish DM models; and insulin (INS) group, treated with subcutaneous injection of long-acting insulin (glargine, 0.5 U x kg(-1) x d(-1)) for 4 weeks after the establishment of DM models. 48 h, 2 weeks, and 4 weeks after the STZ injection to the 2 DM groups oral glucose tolerance test (OGTT) was performed to all rats. Peripheral blood samples were collected from the caudal vein. Serum insulin level was assayed by radioimmunoassay. Total serum cholesterol (TC) and triglyceride (TG) were measured by enzyme-colorimetric method. By the end of experiment the rats were killed with their pancreases taken out. Immunohistochemistry was used to observe the morphological changes of the islet beta and alpha cells. Beta cell and alpha cell masses were calculated by the proportions of positive area in the islet. Proinsulin mRNA level was detected by RT-PCR. Insulin protein content in islets was detected by Western blotting. RESULTS: Four weeks after the insulin intervention against glucotoxicity, the fasting blood glucose and blood glucose 2 h after sugar-taking of the INS group were both significantly lower than those of the DM group (both P < 0.01). The relative beta cell mass of the INS group was 0.38 +/- 0.08, significantly bigger, 2.45 times, that of the DM group (0.11 +/- 0.05, P < 0.01). The relative alpha cells mass in islets of the INS group was 0.16 +/- 0.04, significantly lower, by 43%, than that of the DM group (0.28 +/- 0.15, P < 0.01). The insulin contents in beta cells of the INS group was 0.58 +/- 0.03, significantly higher, by 70.6%, than that of the DM group (0.34 +/- 0.14, P < 0.01). The proinsulin mRNA level of the INS group was 1.52 +/- 0.14, significantly higher, by 20.6%, than that of the DM group. CONCLUSION: The morphology of islet beta, alpha cells in diabetic rats was improved by four weeks of Intervention against glucotoxicity improves the pathology of islet beta and alpha cells in diabetic and insulin synthesis.

[Analyses on the relative factors regarding diabetic nephropathy among 1758 cases of type 2 diabetic patients].

OBJECTIVE: To analyze the prevalence rate of diabetic nephropathy (DN) and the related factors on DN among type 2 diabetic patients. METHODS: A total number of 1758 type 2 diabetic patients who were hospitalized in the Beijing Hospital from 2003 to 2010 were analyzed retrospectively. Three groups were divided according to the rate of urinary albumin excretion (UAER). Patients whose UAER < 20 µg/min belonged to normal albuminuria (NA) group. The ones whose UAER from 20 to 200 µg/min belonged to microalbuminuria (MA) group, and the others whose UAER ≥ 200 µg/min belonged to large albuminuia (LA) group. The clinical characteristics were then compared. The related factors of DN were analyzed. RESULTS: (1) There were 1246 patients in NA group, 408 patients in MA group, and 104 patients in LA group. The constituent ratio of nephropathy was 29.1%. (2) The ages of NA group, MA group and LA group were (59.87 ± 12.77, 62.52 ± 12.74, 64.44 ± 12.74) years old, respectively, with body mass index (BMI) as (24.90 ± 3.42, 25.53 ± 4.00, 25.53 ± 3.91) kg/m(2) respectively; duration of diabetes as (8.39 ± 7.12, 10.77 ± 8.02, 12.84 ± 7.97) years; systolic blood pressure (SBP) as (133.42 ± 18.19, 142.72 ± 20.21, 151.12 ± 21.91) mm Hg; diastolic blood pressure as (78.75 ± 10.66, 80.79 ± 12.21, 83.33 ± 13.61) mm Hg; fasting blood sugar (FBS) as (8.25 ± 3.43, 9.02 ± 3.72, 9.22 ± 4.62) mmol/L; glycated hemoglobin (HbA1c) as (8.88 ± 2.10, 9.34 ± 2.36, 9.10 ± 2.36)%; uric acid (UA) as (288.04 ± 90.41, 307.23 ± 96.96, 374.28 ± 105.47) mmol/L; triglyceride as (1.72 ± 1.51, 2.06 ± 1.88, 1.94 ± 1.42) mmol/L, high density lipoprotein cholesterol as (1.08 ± 0.30, 1.02 ± 0.29, 1.07 ± 0.28) mmol/L; fasting insulin as (9.24 ± 9.02, 11.24 ± 9.74, 11.06 ± 9.29) µU/ml; fasting C peptide as (462.31 ± 289.94, 510.02 ± 350.08, 595.93 ± 445.86) pmol/L. There were significant differences between NA, MA and LA groups in all above items (P < 0.01 or P < 0.05). (3) Logistic regression analysis showed that DN were related with duration of diabetes, BMI, SBP, HbA1c, FBS, UA (OR values were 1.041, 1.055, 1.028, 1.116, 1.100, 1.004 respectively, P < 0.05 or P < 0.01). CONCLUSION: It would be helpful to prevent and retard progression of DN that comprehensively controlling high blood glucose, hypertension, hyperuricemia and body weight of type 2 diabetic patients.