Vitamin E supplementation in streptozotocin-treated rats alters cerebellar and plasma nitric oxide metabolism

Early Intervention of Gastrodin Improved Motor Learning in Diabetic Rats Through Ameliorating Vascular Dysfunction

The mechanism of cognitive dysfunction in diabetes is still unclear. Recently, studies have shown that the cerebellum is involved in cognition. Furthermore, diabetes-induced cerebellar alterations is related to vascular changes. Therefore, we aimed to explore the roles of vascular function in diabetes-induced cerebellar damage and motor learning deficits. Type 1 diabetes was induced by a single injection of streptozotocin in Sprague-Dawley rats. Motor learning was assessed by beam walk test and beam balance test. The pathological changes of the cerebellum were assessed by Hematoxylin and eosin staining and Nissl staining. Apoptosis was evaluated by anti-caspase-3 immunostaining. Protein expression was evaluated by western blotting and double immunofluorescence. Our results have shown that motor learning was impaired in diabetic rats, coupled with damaged Purkinje cells and decreased capillary density in the cerebellum. In addition, the protein expression of neuronal NOS, inducible NOS, endothelial NOS, total nitric oxide, vascular endothelial growth factor and its cognate receptor Flk-1 was decreased in the cerebellum. Gastrodin treatment ameliorated neuronal damage and restored protein expression of relevant factors. Arising from the above, it is suggested that vascular dysfunction and NO signaling deficits in the cerebellum may be the underlying mechanism of early manifestations of cognitive impairment in diabetes, which could be ameliorated by gastrodin intervention.

Efficacy of vitamin E and selenium for the prevention of intra-abdominal adhesions in rats: uterine horn models

OBJECTIVE

This study compares the efficacies of vitamin E and selenium, both individually and in combination, for the prevention of postoperative intra-abdominal adhesions in rats.

METHODS

Forty-seven female rats were divided into five groups. The sham animals (S group, n = 7) were given only laparotomies and intraperitoneally received 0.9% NaCl (2 ml). In the 40 other rats, abrasions of the left uterine horn were performed, followed by intraperitoneal administration of either 2 ml 0.9% NaCl (C group), 10 mg vitamin E (vitamin E group), 0.2 mg/kg selenium (Se group) or 10 mg vitamin E with 0.2 mg/kg selenium (vitamin E + Se group), with 10 animals in each treatment group.

RESULTS

Adhesion formation was significantly reduced in animals in the Se and vitamin E + Se groups (p<0.05). Tissue catalase and glutathione peroxidase activities did not significantly differ between the groups. However, catalase and glutathione peroxidase activities and reduced glutathione levels were slightly increased in the vitamin E, Se and vitamin E + Se groups. In the vitamin E group, malondialdehyde concentrations were significantly lower than in the C group (p<0.05), but no significant differences were present among the S, C, Se and vitamin E + Se groups. Levels of nitric oxide were significantly higher in the C group than in the other groups (p<0.01).

CONCLUSION

Intraperitoneal administration of selenium or combined vitamin E and selenium appears to be effective in preventing intra-abdominal adhesion formation in rat models through the reduction of lipid peroxidation products.

Vitamin E improves learning performance and changes the expression of nitric oxide-producing neurons in the brains of diabetic rats

We investigated the effects of chronic administration of vitamin E on nitric oxide (NO)-producing neurons in the brains of streptozotocin (STZ)-induced diabetic rats using nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry. We further evaluated the effects of diabetes and vitamin E treatment on experimental anxiety and memory processes using the elevated plus maze (EPM) Trial 1/2 protocol. Wistar rats were divided into four groups: normoglycemics (N), normoglycemics treated with vitamin E (NVE), diabetics (D), and diabetics treated with vitamin E (DVE). Diabetes mellitus was induced by a single intraperitoneal injection of STZ (35mg/kg). Vitamin E (100mg/kg) or vehicle was administered orally by gavage (1ml/kg) once each day for 7 weeks. After behavioral testing, the dentate gyrus of the hippocampus (DG), striatum, paraventricular nucleus of the hypothalamus (PVN), supraoptic nucleus (SON), and dorsolateral periaqueductal grey (DLPAG) were analyzed for NADPH-d histochemistry. STZ-induced diabetic rats exhibited decreased locomotor activity and cognitive impairment compared with normoglycemic controls. The number of NADPH-d-positive neurons was increased in the DG, striatum, and DLPAG of diabetic rats. An increase in soma area was detected in all structures analyzed (DG, striatum, PVN, SON, and DLPAG) of STZ-induced diabetic animals. The present study showed that chronic administration of vitamin E ameliorates memory in STZ-induced diabetic rats and revealed that NOS-producing neurons have an increased soma area which can be restored, at least partially, by vitamin E treatment. These results suggest the potential use of vitamin E as an adjuvant therapy for the prevention and treatment of diabetic conditions.

Administration of Ginseng radix decreases nitric oxide synthase expression in the hippocampus of streptozotocin-induced diabetic rats

Nitric oxide (NO) is synthesized from L-arginine by nitric oxide synthase (NOS). Alternation of NOS expression is implicated in the pathogenesis of numerous secondary complications of diabetes. Aqueous extract of Ginseng radix has traditionally been used for the various disorders including diabetes. In this study, the effect of Ginseng radix on the NOS expression in the hippocampus of streptozotocin (STZ)-induced diabetic rats was investigated via nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry. Enhanced NOS expression was detected in the hippocampus of diabetic rats and administration of Ginseng radix suppressed NOS expression. Ginseng radix may aid the treatment of central nervous system complications in diabetes.