BACKGROUND: Oxygen-derived free radicals are produced during non-enzymatic glycosylation of diabetic protein and accompanied with decrease in nitrogen monoxide (NO) synthesis so as to cause the calcium increase in cell,evacuation of pykno-granule and apoptosis induced by activating endoenzyme.OBJECTIVE: To observe the effects of non-enzymatic glycosylation inhibitor-aminoguanidine on apoptosis of cardiac myocyte and cardiac function in diabetic rats.DESIGN: Completely randomized grouping design and controlled study.SETTING: Pharmacological Department of Jinzhou Medical College.MATERIALS: The experiment was completed at the Central Laboratory of Jinzhou Medical College between September 2002 and March 2003. Totally 54 male SD rats with 2-month old were selected.METHODS: Totally 36 rats were selected to establish diabetic model 60 mg/kg of streptozotocin were injected into the caudal vein. If blood glucose of rats was more than 16.7 mmol/L, the establishment of diabetic model was successful. Model rats were divided into diabetes group and aminoguanidine (AG) group with 18 in each group. Rats in each group were also divided into two 12-week groups with 8 and 12 respectively. Another 18 rats were determined as the control group at 2 time points: 12 weeks (n=8) and 24 weeks (n=10). Rats in each group were fed for 12 and 24in other two groups. Calculation of mass index was [heart (mg)/body mass (g)]. Myocardial tissue of left ventricle was taken out and observed with transmission electron microscope and then stained with in situ end-labeling (ISEL) method. Number of positive nucleus was counted with 10 × 10 ocular lens check system and with 10 fields ISEL method; meanwhile, their average was obtained.MAIN OUTCOME MEASURES: Whether there was apoptosis of cardiac cell and the effect on AG in changes of cardiac structure and function of diabetic rats or not.RESULTS: Eight rats were lost during the experiment because of death mass: That of rats in the 12-week and 24-week diabetic group was higher decrease and increase rate of pressure in left ventricle: That of rats in the 12-week and 24-week diabetic group was lower than that in the control in left ventricle: That in 24-week diabetes group was obviously lower than diabetic group was obviously more than that in AG group (P ＜ 0.01), and that in 24-week diabetes group was obviously more than that in 12-week Apoptosis could be observed in myocardial cell in diabetic group.CONCLUSION: Apoptosis of myocardial cell plays an important role in the development of heart failure in diabetic rats. AG can reduce the apoptosis of myocardial cell and decrease the myocardial pathomorphological abnormality.

Objective To explore the effects of salidroside(SAL)on high glucose-induced epithelial-mesenchymal transition in ARPE-19 cells and its mechanism.Methods The appropriate glucose concentration for stimulating ARPE-19 cell proliferation was determined to be 50 mmol·L-1 using the MTT method.ARPE-19 cells were divided into the normal control group(Control group)(cultured with 5 mmol·L-1 D-glucose and 45 mmol·L-1 mannitol),high glucose group(HG group)(cultured with 50 mmol·L-1 glucose),HG+low SAL group,HG+medium SAL group,and HG+high SAL group,with low,medium,and high SAL concentrations of 20 μmol·L-1,80 μmol·L-1,and 320 μmol·L-1,respective-ly.After 4 hours of SAL pretreatment,50 mmol·L-1 glucose was added to treat cells for 48 hours.The cell proliferation rate was detected using the MTT method;the cell migration activity was detected using the scratch experiment;the expres-sion levels of α-smooth muscle actin(α-SMA)and Vimentin in cells were measured using the immunofluorescence;the protein expression levels of α-SMA,Vimentin,fibronectin(FN),collagen type Ⅰ(Col Ⅰ),E-Cadherin,transforming growth factor-β1(TGF-β1),p-Smad2 and p-Smad3 in cells were measured using Western blot.Results Compared with the Control group,the proliferation rate and wound healing percentage of ARPE-19 cells in the HG group increased;the relative expression levels of α-SMA,Vimentin,FN,and Col Ⅰ proteins in the cells increased;the relative expression level of E-cad-herin protein in the cells decreased;the relative expression levels of TGF-β1,p-Smad2,and p-Smad3 proteins in the cells increased,and the differences were statistically significant(all P＜0.01).Compared with the HG group,the proliferation rate and wound healing percentage of ARPE-19 cells in the HG+low SAL group,HG+medium SAL group,and HG+high SAL group decreased,the relative expression levels of α-SMA,Vimentin,FN,Col Ⅰ,TGF-β1,p-Smad2,and p-Smad3 pro-teins in the cells decreased in a concentration dependent manner,while the relative expression level of E-cadherin protein increased in a concentration dependent manner,and the differences were statistically significant(all P＜0.05).Conclu-sion SAL can reduce the proliferation and migration ability of high glucose-induced ARPE-19 cells and intervene in their epithelial-mesenchymal transition process.This may be related to SAL's inhibition of the TGF-β/Smads signaling pathway in ARPE-19 cells.