Estudo do efeito do acasalamento consaguíneo e da redução do número de filhotes sobre o fenótipo de obesidade em ratos Wistar

Abstract

Obesity has been considered a worldwide epidemic described as "globesity", becoming a serious public health problem today. It is known that the risk of developing obesity in adulthood may be influenced by inadequate nutrition in the lactational phase of the newborn. "Metabolic programming" is what we call the process by which early life factors can influence offspring health in adulthood. Studies with animal models favoring the excess of food consumption or the reduction of the number of pups in the litter, suggest that the obesity can be transmitted through multiple generations through epigenetic mechanisms. In this context, the present work aimed to propose a new model of study where we evaluated the effect of the association of reduction of pups number and consanguine mating on obesity in Wistar rats for 5 generations. The experimental design of this study intends to develop and evaluate 20 generations. If the phenotypic characteristics of obesity acquired until the last generation were maintained, this could be an alternative available to researchers, bringing innumerable benefits to the research as a reduction of time, cost and animals sacrificed in experiments. For this study, the experimental group was formed by rats coming from non-consanguineous breeding, which when adults mated and had their litters reduced to 2 males and 2 females. These animals that underwent the first manipulation of the litter were called Generator formation and from this generation the breeds were mated to give origin to G1. From G1, the two procedures of litter reduction and sibling crossing were then performed, consecutively, up to G5. The results obtained from these generations were compared to the results of a control group, where the animals mated by non - blood crossbreeding and the resulting litters were not reduced. In this work, the results of generations 1, 3, 5 and of the control group will be presented since they were considered representative of generations 2 and 4. In each generation all the males were sacrificed to collect the blood samples where the following were evaluated (body mass, Lee's index, dietary intake, retroperitoneal adiposity, hemimandibular morphometry, number of goblet cells, and bowel length). The parameters were analyzed by the ANOVA method, with Tukey test powders and Student t test. Compared with the control group, inbred animals showed an increase in feed intake, body mass, retroperitoneal fat, Lee index, LDL and reduction of HDL, VLDL, total cholesterol, triglycerides and glycemia. In the evaluation of the intestine there was a reduction in the number of goblet cells and an increase in intestinal length. The morphometrics of the hemimandibula were used as markers of possible epigenetic alterations and the results showed a reduction of the mandibular mass in G3 and G5 and morphometric alterations that indicate the reduction of the size. It is concluded, in this study, that the reduction of the number of rats with the inbreeding keeps the phenotypic characteristics of obesity in the studied generations.