Total triterpene acids, isolated from Corni Fructus, ameliorate progression of renal damage in streptozotocin-induced diabetic rats.

OBJECTIVE: To investigate whether total triterpene acids (TTAs), isolated from Cornus Fructus, attenuates renal function by reducing oxidative stress and down-regulating the expression of transforming growth factor ß1 (TGF-ß1). METHODS: Diabetes was induced by an injection of streptozotocin (40 mg/kg intravenously). Thirty rats were randomly divided into three groups: control group, diabetic model group and TTAs treatment group (50 mg/kg, intragastrically) administrated for 8 weeks from 5th to 12th week. All rats were anaesthetized and then were killed to remove kidneys. The renal function and redox enzyme system parameters were tested. Glomerular morphology was observed by a light microscopy. Immunohistochemistry and Western blot assays were employed to determine the protein levels of TGF-ß1. RESULTS: TTAs attenuated the levels of urinary protein, serum creatinine and blood urea nitrogen, although it did not significantly reduce the level of glucose. In addition, TTAs decreased the malondialdehyde while increased superoxide dismutase, catalase and glutathione peroxide activities in diabetic rats. The renal pathological changes in TTAs treatment group were ameliorated. Furthermore, TTAs also ameliorated the expression of TGF-ß1. CONCLUSION: TTAs improved renal function via reducing oxidative stress and down-regulation the expression of TGF-ß1 in diabetic rats.

[Protective effect of terpenes from fructus corni on the cardiomyopathy in alloxan-induced diabetic mice].

OBJECTIVE: To investigate the protective effects of terpenes from fructus corni (TFC) on diabetic cardiomyopathy (DCM). METHODS: Diabetes was produced by a single injection of alloxan (220 mg/kg, i.p.) in mice. The fasting blood glucose of mice were tested 15 days later and that greater than 13.9 mmol/L were regarded as the diabetic mice which were divided randomly into the model and TFC groups. TFC dissolved by physiological saline (P.O, 80 mg/kg) was administrated to the TFC group for successive 8 weeks since the 15th day. RESULTS: Compared to the control group, the weight index increased significantly. The level of superoxide dismutase (SOD) was markedly decreased and malondialdehyde(MDA), the inflammatory factors (TNF-alpha, IL-6) were obviously increased in myocardium. The histopathological examination suggested that myocardial cells disarranged, swelling and the intercellular space increased in model group. It also showed the infiltration of inflammatory cells and fibroblasts in TFC group. The above change was improved significantly. CONCLUSION: TFC ameliorated the alterations of cardiomyopathy in diabetic mice induced by alloxan. the mechanism might be related to decrease blood glucose, antioxidative stress and inflammatory factors.

Protective effect of Icariin on the early stage of experimental diabetic nephropathy induced by streptozotocin via modulating transforming growth factor ß1 and type IV collagen expression in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Icariin is a major constituent of flavonoid isolated from the plant Herba epimedii, which is used as a traditional Chinese medicine to nourish the kidney and reinforce yang. Therefore, the pharmacological studied of its diabetic nephropathy effect was undertaken to validate its traditional use. MATERIALS AND METHODS: Diabetes was induced in male Sprague-Dawley rats by an injection of streptozotocin (40 mg/kg i.v.). Sustained blood glucose levels (>16.7 mmol/l) were considered as diabetic and selected for experimentation. Thirty rats were randomly divided into three groups: control, diabetic, diabetic+Icariin (80 mg/kg, i.g.) administered 8 weeks from 5th to 12th week. Experiment was carried out at the beginning of 13th week. All rats were anaesthetized and then were killed to remove kidneys. Blood glucose, serum creatinine (Cr), blood urea nitrogen (BUN), the activity of superoxide dismutase (SOD), malondialdehyde (MDA) and hydroxyproline (Hyp) in the kidney tissue were measured. Glomerular morphology was observed by light microscopy. Immunohistochemistry and Western blot were employed to determine the proteins levels of TGF-ß(1) and type IV collagen. RESULTS: The enhancement of Cr and BUN was found in model group, which was significantly attenuated by treatment with Icariin. Meanwhile, elevated MDA and Hyp levels in renal tissue as well as decreased SOD activities in renal tissue were significantly remitted by Icariin. The renal pathological changes in Icariin treatment group were ameliorated. Furthermore, the Icariin decreased the expression of TGF-ß(1) and collagen IV protein. CONCLUSIONS: Icariin can evidently relieve renal damage in rats with diabetic nephropathy induced by STZ, which might be related to modulating the expression of collagen IV and TGF-ß(1) protein.