Aging affects the response of female rats to a hypercaloric diet

Metabolic syndrome is a major risk factor for the development of cardiovascular diseases and diabetes, among other conditions. Studies have shown that aging and metabolic syndrome share several metabolic alterations, and that aged individuals, in particular females, are at an increased risk of developing metabolic disorders. Although several studies have investigated the effects of hypercaloric diets in the development of obesity and metabolic syndrome in young animals, few studies have investigated these parameters in aged animals, especially in females. Therefore, the aim of this study was to investigate the effects of a hypercaloric diet in metabolic parameters of young and aged female rats, including its effects on lipid and glycemic profile and on liver lipid content. When compared to young animals, the aged rats presented increased serum levels of triglycerides and decreased serum levels of HDL cholesterol and glycemia, as well as increased hepatic levels of triglycerides and total cholesterol. The hypercaloric diet increased food intake, body weight gain and adiposity index, leading both young and aged animals to a dyslipidemia, represented by increased serum levels of triglycerides. The hypercaloric diet increased the glycemia and the HOMA index only in the young animals. On the other hand, the diet increased the frequency of hepatocellular microvacuolar degeneration only in the aged animals. In summary, it was observed that the females from different ages respond differently to hypercaloric diet intake: while the aged animals were more resistant to the changes in the glycemic profile, they were more susceptible to the hepatic damage caused by this diet.