ION CHANNEL EXPRESSION IN THE BRAIN AREAS OF HIGH-FAT DIET FED RATS

Obesity is associated with the development of cerebrovascular diseases promoting cognitive decline. High Body Mass Index has been suggested as a risk factor for Alzheimer’s disease and vascular dementia and has been associated with poorer cognitive performance in population-based studies. Evidence suggests that transient receptor potential (TRP) ion channels dysfunction significantly contributes to the physiopathology of metabolic and neurological disorders. Mutations in genes encoding TRP channels are the cause of several inherited diseases in humans (the socalled ‘TRP channelopathies’) that affect the cardiovascular, renal, skeletal, and nervous systems. This study aimed to evaluate the effects of a high-fat diet on ion channel expression in the brain of diet-induced obesity (DIO) rats. DIO rats were studied after 17 weeks under a hypercaloric diet. Moreover, groups of DIO rats were supplemented with tart cherries seeds powder (DS) or seeds powder plus tart cherries juice (DES) to evaluate the possible protective effects. DIO rats were compared to the control rats with a standard diet (CHOW). To determine the systemic effects of high-calorie diet exposure, we examined food consumption, fat mass content and fasting glycemia, insulin levels, cholesterol, and triglycerides. qRT-PCR, Western blot, and morphological analysis were performed in the frontal cortex and hippocampus. After 17 weeks of fat diet, rats increased significantly their body weight in comparison to the CHOW rats. No differences in body weight were observed in DS and DES rats compared to age-matched DIO rats. In DIO rats TRPC1 and TRPC6 were up-regulated in the hippocampus, while they were down regulated in the frontal cortex. In the case of TRPM2 expression instead, was increased both in the hippocampus and in the frontal cortex. All these data are confirmed by immunohistochemical and Western blot analysis. Supplemented DIO rats showing a different modulation on TRPC1, TRPC6, TRPM2, and TRPV1 ion channel expression in the hippocampus and the frontal cortex, possibly related to the positive effects of anthocyanins on reactive gliosis. The identification of neurodegenerative changes in DIO rats involving the ion channels expression may represent the first insight to better characterize the neuronal changes occurring in obesity. Further studies are needed to clarify the benefits of tart cherry supplementation on the prevention of cerebrovascular alterations.