Investigation of effect of alpha lipoic acid on brain tissue in streptozotocin induced diabetic rat model

Background/Aim: Neuropathy due to diabetic complications causes structural and functional impairments in brain tissue, causing cognitive functions to deteriorate. We aimed to elucidate the mechanism of neuropathy in Streptozotocin (STZ) induced diabetic rats and to investigate the effects of Alpha Lipoic Acid (ALA) administration on brain tissue from biochemical histological and physiological aspects. Materials and Methods: Forty Wistar albino male rats control, STZ ALA and STZ+ALA were divided into four groups. Single dose 50 mg/kg STZ ip to create diabetes, ALA was administered orally daily for six weeks at 100 mg/kg/day. Cognitive functions were assessed by MWM during the last week of treatment. Brain tissues of the sacrificed rats were divided into hippocampus, cortex, hypothalamus and striatum regions structures for histological and oxidant-antioxidant parameters. Results: The changes in cognitive functions assessed by MWM were deteriorated the STZ group in according to the control and ALA group, whereas the results were improved the STZ + ALA group in according to the STZ group (p<0.05). SOD, CAT, and GSH-Px activities decreased in the STZ group compared to the control group were statistically significantly increased in the STZ + ALA group compared to the STZ group. MDA and PC levels increased in the STZ group, and decreased in the STZ + ALA group compared to the STZ group (p<0.05). According to our histological and light microscopic findings, it was determined that some parts of STZ + ALA group of microscopic and ultrastructural damage and degeneration findings in the sections of STZ group diminished considerably. Conclusions: Distorted balance of oxidant-antioxidant in the rat brain tissue caused structural distortions in nerve cells, resulting in cognitive dysfunctions in the STZ-induced diabetes model. ALA is effective to ameliorate cell damage and cognitive functions in brain tissue by its antioxidant and neuroprotective effect.