Vitamin D Improves Learning and Memory Impairment in Streptozotocin-Induced Diabetic Mice

Rosinidin Protects Streptozotocin-Induced Memory Impairment-Activated Neurotoxicity by Suppressing Oxidative Stress and Inflammatory Mediators in Rats

Background and Objectives: To assess the antioxidant and neuroprotective role of rosinidin on rat memory impairment that is induced by streptozotocin. Materials and Methods: Wistar rats were given an intraperitoneal (i.p) injection of streptozotocin (60 mg/kg) followed by treatment with rosinidin at selective doses (10 and 20 mg/kg) for 30 days. The behavioral parameters were estimated by Y-maze test and Morris water test. Biochemical parameters such as acetylcholinesterase (AChE), choline aacetyltransferase (ChAT), and nitric oxide, and antioxidants such as glutathione transferase (GSH), superoxide dismutase (SOD) IL-6, IL-10, Nrf2, and BDNF, were determined. Results: The study results revealed that rosinidin improved cognition by reverting the behavioral parameters. The treatment with rosinidin restored the antioxidant enzymes and inflammatory cytokines. Conclusions: From the results, it has been proven that rosinidin possesses antioxidant, anti-amnesic, and anti-inflammatory activity. Rosinidin improved the cognitive and behavioral deficits that were induced by streptozotocin. Furthermore, 20 mg/kg rosinidin was found to have strong protective action against streptozotocin-induced toxicity.

Effects of cinnamic acid on memory deficits and brain oxidative stress in streptozotocin-induced diabetic mice

The present study aimed to evaluate the cinnamic acid effect on memory impairment, oxidative stress, and cholinergic dysfunction in streptozotocin (STZ)-induced diabetic model in mice. In this experimental study, 48 male Naval Medical Research Institute (NMRI) mice (30–35 g) were chosen and were randomly divided into six groups: control, cinnamic acid (20 mg/kg day, i.p. ), diabetic, and cinnamic acid-treated diabetic (10, 20 and 40 mg/kg day, i.p. ). Memory was impaired by administering an intraperitoneal STZ injection of 50 mg/kg. Cinnamic acid was injected for 40 days starting from the 21st day after confirming STZ-induced dementia to observe its therapeutic effect. Memory function was assessed using cross-arm maze, morris water maze and passive avoidance test. After the administration, biochemical parameters of oxidative stress and cholinergic function were estimated in the brain. Present data indicated that inducing STZ caused significant memory impairment, whereas administration of cinnamic acid caused significant and dose-dependent memory improvement. Assessment of brain homogenates indicated cholinergic dysfunction, increase in lipid peroxidation and reactive oxygen species (ROS) levels, and decrease in glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) activities in the diabetic group compared to the control animals, whereas cinnamic acid administration ameliorated these indices in the diabetic mice. The present study demonstrated that cinnamic acid improves memory by reducing the oxidative stress and cholinergic dysfunction in the brain of diabetic mice.

The Protective Effect of L-arginine in Cisplatin-induced Nephrotoxicity in Streptozotocin-induced Diabetic Rats

Background:

Cisplatin (CP) is accompanied with a nephrotoxicity. L-arginine (LA) plays an important role in the regulation of renal function. The present study was designed to investigate the protective role of LA supplementation in CP-induced nephrotoxicity in a diabetic rat's model.

Materials and Methods:

Sixteen adult female and male Wistar rats were used and they received a single dose of streptozotocin (STZ) (60 mg/kg i.p.). Diabetic female and male rats were arranged as groups 1–5 and groups 6–10, respectively. Groups 1 and 6 (LA groups) received LA alone. Groups 2 and 7 (CP groups) received CP alone. Groups 3 and 8 (CP + LA [PT] groups) received LA as prophylaxis and then treated with LA and CP. Groups 4 and 9 (CP + LA [T] groups) were treated with LA and CP simultaneously. Groups 5 and 10 (CP + LA [P] groups) received LA as prophylaxis and then treated with CP.

Results:

The serum creatinine (Cr) level of males in Groups 8 and 9 was significantly increased when compared with LA and CP (P < 0.05), whereas no differences were observed in Cr level in female groups. Blood urea nitrogen/Cr ratio and kidney weight were reduced in all CP-receiving male rats. Such observation was not seen in female rats. Different results related to weight loss were obtained between male and female animals. The kidney tissue damage score in CP + LA (PT) male group was significantly greater than CP group (P < 0.05).

Conclusion:

Our findings indicate that administration of LA in female and male rats has no protective effect on the severity of nephrotoxicity induced by CP in diabetic rats.

Vitamin D administration, cognitive function, BBB permeability and neuroinflammatory factors in high-fat diet-induced obese rats

OBJECTIVES

The purpose of this research was to investigate the effects of vitamin D administration on cognitive function, nuclear factor-κB (NF-κB), brain-derived neurotrophic factor (BDNF) concentration in the hippocampus and blood-brain barrier (BBB) permeability in high-fat diet (HFD)-induced obese rats.

METHODS

Male Wistar rats were fed either a control diet or HFD for 16 weeks (n=20); then, each group was randomized into two subgroups supplemented orally with 500 IU kg^-1 vitamin D for 5 weeks. A Morris water maze (MWM) test was performed at the 21st week to examine cognitive function. BBB permeability was characterized by Evans blue dye in the hippocampus. BDNF and NF-κB concentrations in the hippocampus and serum vitamin D concentrations were also measured.

RESULTS

HFD led to a significant delay in escape latency time and reduced time of MWM probe test because of increased NF-κB and decreased BDNF concentrations in the hippocampus. Vitamin D supplementation in the HFD group significantly reduced body weight, NF-κB concentrations, BBB permeability and increased BDNF concentrations in the hippocampus.

CONCLUSIONS

Vitamin D reversed HFD-induced cognitive impairments by reduction of the NF-κB and elevation of BDNF concentrations and modulation of the BBB permeability in rats' hippocampus.