Efeito da suplementação de quercetina e da dieta hiperlipídica no estresse oxidativo de testículos de ratos Wistar

Abstract

A high-fat diet (HFD) in rats causes the appearance of hepatic steatosis and predisposes the animals to glucose intolerance, dyslipidemia and oxidative stress. It is known that a HFD also affects fertility, causing testicular oxidative stress and impairing sperm production in these animals. Quercetin is a flavonoid that has antioxidant, anti- inflammatory and lipolytic action, being a potential supplement in the fight against oxidative stress caused by a HFD and its deleterious effects on reproduction. The aim of this study was to evaluate quercetin supplementation at doses of 10 mg and 20 mg per day on reproductive organ weights, sperm motility and morphology, testicular morphometry, expression of inflammatory and antioxidant genes in the testes and testicular oxidative profile of rat models submitted to a diet rich in animal fat and fructose. Chapter I aims to review the main aspects involving obesity, the metabolic syndrome, diets rich in lipids and oxidative stress in male reproduction, as well as to address what is known so far about quercetin supplementation as an agent antioxidant. Chapter II is an article in the norms of the scientific journal that will be submitted and describes an experimental study carried out with the objective of verifying the effect of quercetin supplementation on the oxidative stress of the testicles of rats submitted to a diet rich in fats. In this experiment, 24 Wistar rats were divided into 4 experimental groups (n=6): CT (rats fed a basal diet and supplemented with 0 mg/day quercetin gum); HF (rats fed HFD, which consisted of adding 30% pork lard and 20% fructose to the commercial feed and supplemented with 0 mg/day of quercetin gum); HFQ10 (rats fed HFD and supplemented with quercetin gum 10 mg/day); and HFQ20 (rats fed HFD and supplemented with 20 mg/day quercetin gum). The experiment lasted 4 months and quercetin gum supplementation started after two months of consumption of basal diet or HFD. At the end of the experiment, the testes, epididymis and vas deferens were collected and weighed, the testes were used for gene expression, oxidative profile analysis and morphometric analysis. Duct spermatozoa were analyzed for sperm motility and morphology. The HFD groups had lower dietary intake and lower body, epididymal and ductal weights, regardless

of the presence of quercetin. There was no difference between groups in testes weight, germinal epithelium diameter, sperm motility and morphology, and expression of testicular inflammatory genes (P>0.05). Although Sod2 gene expression in the testes was higher in the HF group, there was a reduction in the oxidative stress index and oxidized glutathione in rats in the HF20 group when compared to the HF group. It is concluded that daily quercetin supplementation dose-dependently reduces testicular oxidative stress in rats fed a hiperlipidic diet.