Protective effects of N(G)-nitro-L-arginine methyl ester and metallothioneins on excess nitric oxide toxicity in trinitrobenzene sulfonic acid-induced rat colitis.

OBJECTIVE: To evaluate the protective effects of N(G)-nitro-L-arginine methyl ester (L-NAME) and metallothioneins on excess nitric oxide toxicity in trinitrobenzene sulfonic acid (TNBS)-induced rat colitis. STUDY DESIGN: In this study, 70 rats were assigned to 7 groups of controls, and colitis was induced with 120 mg/kg TNBS, 35 mg/kg L-NAME, and 1 and 2 mg/kg metallothionein 1 (MT1) and metallothionein 2 (MT2), respectively. A day after the administration of TNBS, L-NAME, MT1 and MT2 were given intraperitoneally for 3 days to the experimental groups. After the administration of TNBS, dissections of the rats in the L-NAME, MT1 and MT2 groups were performed at 3-day periods under ether anesthesia, and whole blood, bone marrow and colon were obtained. RESULTS: On the third day, red and white blood cell values were increased, while platelet and bone marrow granule cells decreased in the L-NAME- and TNBS-induced group. On the third day, all the blood values increased in MT1 (1 and 2 mg/kg) and MT2 (1 and 2 mg/kg) in the TNBS-administered groups. Histologic findings were macroscopic score, ulcer, loss of mucous cells, crypt abscess, inflammatory cyst, mucosa atrophy, edema, vascular dilatation and induced nitric oxide synthetase, which increased in the descending colon in the colitis rats, while it was decreased rats given L-NAME, MT1 and MT2 administration. CONCLUSION: The results suggest that MT1 and MT2 are more effective in protecting against the toxic effects of excess nitric oxide as compared with L-NAME in the colitis rats.

Protective effects of vitamin E on central nervous system in streptozotocin-induced diabetic rats.

OBJECTIVE: To evaluate the histopathological and antioxidant effects of vitamin E (VE) treatment on brain tissue in streptozotocin (STZ)-induced diabetic rats. METHODS: Thirty two male Wistar albino rats were used. The study comprised four groups of 8 rats: Group A - untreated group, group B - diabetic group, group C - VE and group D - diabetic plus VE. In the diabetic groups, diabetes was induced by a single intraperitoneal injection of 65 mg/kg STZ. Vitamin E was given 50 mg/kg/day i.p. for three weeks. Concentrations of glucose, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were detected in the haemolysate. RESULTS: Glucose concentrations were increased in the blood of the STZ-treated rats compared with those in the diabetic groups (group B and D). The MDA concentrations in the brain from diabetic rats increased, whereas the GPx, SOD, CAT concentrations decreased. Treatment with VE returned concentrations of MDA, GPx, SOD and CAT toward control values. The MDA concentration in the diabetic group (20.65+/-2.24 nmol/mg Hb) was decreased compared with the VE treated group (15.54+/-1.32 nmol/mg Hb). There were no pathological differences between untreated and VE treated rats' brains. Neuronal ischemic damages were determined in STZ-induced diabetic rats. Ischemic neuronal alterations in group B (diabetic) had more damage than group D (diabetic + VE). CONCLUSION: The study revealed neuroprotective effects of VE on ischemic damage in diabetic central neuronal cells, caused by diabetic oxidative stress.

The effects of acarbose and Rumex patientia L. on ultrastructural and biochemical changes of pancreatic B cells in streptozotocin-induced diabetic rats.

This study was performed to observe the effects of acarbose and Rumex patientia on morphological change of pancreatic B cells in streptozotocin (STZ)-induced diabetic (type 2) rats. Two-day-old Wistar albino rats were intraperitoneally injected with 100mg/kg of STZ or vehicle alone for control. Vehicle and STZ given rats were divided into six groups (1st, 2nd and the 3rd groups are control; the 4th, 5th and 6th groups are STZ groups). The 1st and the 4th groups received water, the 2nd and the 5th groups received 40 mg acarbose/100 g feed, the 3rd and the 6th groups received 2% decoction of Rumex patientia grain. During experimentation period, blood glucose levels were checked periodically, and HbA1c level was measured from cardiac blood at the end of the experiment. Pancreas tissues were examined by electron microscope. Glucose and HbA1c levels increased by STZ were decreased by acarbose and Rumex patientia. Morphologically, we found a mitochondrial vacuolization and swelling as well as dilatation of the endoplasmic reticulum in the B cells of STZ-induced diabetic rats. Also, a decrease in the secretory granules of B cells was observed in the STZ-induced diabetic group. No pathological changes were observed in the STZ+acarbose group. In the STZ+Rumex patientia group, a weak swelling in the B cells was observed in the some of the mitochondria.