Investigation of physiopathological changes caused by obesity and exercise in the brain

In this study, changes by diet-induced obesity and exercise in gene expression of neurotransmitters and neuropeptides and their receptors, which are considered to be directly or indirectly related to energy metabolism in the brain, have been investigated. Through the behavioral tests, the effects of obesity and exercise on cognitive, affective and sexual functions were observed. Thus, it is aimed to elucidate the cellular mechanisms that underlie the effects of obesity and exercise. In the study, 40 male Sprague-Dawley rats were divided into 4 groups with 10 animals in each group after they were weaned: Group I (Control), Group II (exercise trained with motorize treadmill), Group III (diet-induced obesity) and Group IV (diet induced obesity and exercise trained group). For the obesity model fat-rich diet were applied. Behavioral tests were applied to all groups during certain periods during the study. At the end of the study, blood samples were taken from the animals for biochemical analysis, and brain samples were taken for immunofluorescence and gene expression analysis. Expression of kisspeptin in the arcuate nucleus (ARC) of the hypothalamus was examined with immunofluorescence method. In addition, obesity and exercise-related gene expressions in the hypothalamus, hippocampus, prefrontal cortex and corpus striatum regions were analyzed with Real Time Polymerase Chain Reaction (RT-PCR). The behavioral test results showed that anxiety and depression symptoms generally increased in the high fat diet induced obese group compared to the other groups. Sexual behavior test results showed that sexual performance decreased significantly in the obese group. It has been observed that when these animals are exercised, their symptoms are delayed. Changes in the expression of kisspeptin in the arcuate nucleus for the first time in this study and the results revealed by gene expression analysis are explanatory of the mechanisms underlying the behavioral tests. In conclusion, the effects of obesity and exercise on affective, cognitive and sexual functions have been explained with biochemical, gene analysis and immunohistochemical studies in the brain by the changes at the cellular and molecular level.