TLR2 knockout protects against diabetes-mediated changes in cerebral perfusion and cognitive deficits.

The risk of cognitive decline in diabetes (Type 1 and Type 2) is significantly greater compared with normoglycemic patients, and the risk of developing dementia in diabetic patients is doubled. The etiology for this is likely multifactorial, but one mechanism that has gained increasing attention is decreased cerebral perfusion as a result of cerebrovascular dysfunction. The innate immune system has been shown to play a role in diabetic vascular complications, notably through the Toll-like receptor (TLR)-stimulated release of proinflammatory cytokines and chemokines that lead to vascular damage. TLR2 has been implicated in playing a crucial role in the development of diabetic microvascular complications, such as nephropathy, and thus, we hypothesized that TLR2-mediated cerebrovascular dysfunction leads to decreased cerebral blood flow (CBF) and cognitive impairment in diabetes. Knockout of TLR2 conferred protection from impaired CBF in early-stage diabetes and from hyperperfusion in long-term diabetes, prevented the development of endothelium-dependent vascular dysfunction in diabetes, created a hyperactive and anxiolytic phenotype, and protected against diabetes-induced impairment of long-term hippocampal and prefrontal cortex-mediated fear learning. In conclusion, these findings support the involvement of TLR2 in the pathogenesis of diabetic vascular disease and cognitive impairment.

Neuroprotective effect of sesame seed oil in 6-hydroxydopamine induced neurotoxicity in mice model: cellular, biochemical and neurochemical evidence.

Natural antioxidants have shown a remarkable reduction in oxidative stress due to excess formation of reactive oxygen species by enhancing antioxidant mechanism in the neurodegenerative disorders. Sesame seed oil (SO) is one of the most important edible oil in India as well as in Asian countries and has potent antioxidant properties thus the present study evaluated the neuroprotective effect of SO by using 6-Hydroxydopamine (6-OHDA)-induced Parkinson's disease model in mice. The mice were fed an SO mix diet for 15 days and then 6-OHDA was injected into the right striatum of mice brain. Three weeks after 6-OHDA infusion, mice were sacrificed and the striatum was removed. The neuroprotective role of SO on the activities of antioxidant and non-antioxidant enzymes such as glutathione reductase (GR), glutathione-S-transferase (GST), glutathione peroxidase (GPx), catalase (CAT) and content of glutathione (GSH) and thiobarbituric acid reactive substance (TBARS) were studied in the striatum. The activities of all the above-mentioned enzymes decreased significantly in 6-OHDA group (Lesioned) when compared with Sham. The pretreatment of SO on antioxidant mechanism and dopamine level in the brain had shown some significant improvement in Lesion+SO (L+SO) group when compared with Lesioned group. However, NADPH oxidase subunit, Nox2 and inflammatory stimulator Cox2 expression was increased as well as antioxidant MnSOD level was decreased in Lesioned group while SO showed the inhibitory effect on the activation of Nox2 and Cox2 and restored MnSOD expression in L+SO group. Increased tyrosine hydroxylase (TH) expression in substantia nigra as well as dopamine and its metabolite DOPAC level in L+SO group also support our findings that SO may inhibit activation of NADPH oxidase dependent inflammatory mechanism due to 6-OHDA induced neurotoxicity in mice.