Efeitos antiobesidade e antiansiogênico da prática precoce de natação com sobrecarga em ratas submetidas a dieta Ociental.

Abstract

Obesity has a multifactorial origin but with a strong relationship between the consumption of foods with high caloric density, combined with an inactive lifestyle. It is characterized by excessive accumulation of adipose tissue, causing low-grade systemic inflammation. This inflamed environment leads to metabolic diseases, as well as behavioral changes such as depression, anxiety and memory problems. The western diet (OD) is composed of palatable foods, which trigger hyperphagia, resulting in a positive caloric balance and adipocyte hypertrophy. Studies indicate the efficiency of the practice of physical exercises for weight loss, improvement of cognitive wellbeing and physical conditioning. The objective of this work was to analyze the influence of early physical exercise in different weekly volumes of execution on the development of obesity and on the behavior of rats submitted to an obesogenic diet. Seventy female Wistar rats were used, divided into 3 food groups and 3 OD groups: sedentary diet (RS), sporadic exercise diet (RE), regular exercise diet (RR), sedentary diet (DS), dietsporadic exercise (DE) and diet-regular exercise (RD). The exercised groups performed swimming, lasting 45 minutes each session. The RR and DR groups performed the exercises 5 days a week and the RE and DE groups 1 day a week. The behavioral tests performed verified depressive, anxious and memory-related behavior. The rats were submitted to the elevated plus maze (LCE), open field (CA), object recognition (RO), splash test (ST) and forced swimming (NF). DO increased the total fat stores of DS animals by 132%, while exercise attenuated this gain by 35 (DR) and 23% (DE). Furthermore, the percentage of fat in the DR group was significantly lower than in the DS group (6.3 and 9.8%, respectively). OD also increased the rats' final weight by 60%, which was partially attenuated by exercise (DE: 31 and DR 38% heavier than the RS group). Obese rats had 55% higher plasma triglyceride concentrations than control (RS), but regular exercise (DR) was more effective in attenuating this gain (DR: 34% lower than DS) than sporadic exercise (DE: 15 % less than DS). We found no significant differences in blood glucose, cholesterol and TNFα concentrations between the groups. The exercised animals showed anxiety-like behavior, there was a reduction of approximately 43% of the time in the open arms of the DE and DR groups in the LCE. There was also an increase in the caloric intake of DE and DR animals. The DS animals showed mild depressive-like behavior only in the ST, with a 67% reduction in grooming time when compared to the RS group, but there were no differences in the NF. The AC tests and entries in the closed arm of the LCE demonstrate that there were no changes in the animals' motility. We found no significant differences in the OR test. Regular exercise was more effective than sporadic exercise in attenuating the increase in fat stores and triglyceride concentrations in the animals. The exercise increased the consumption of hyperpalatable foods, but without affecting the final weight gain, which may be associated with the use of females and the stress of swimming training, which seems to have provoked an anxious-like behavior. Obesity did not cause changes in mobility and memory, however, it seems to have induced a mild depressive-like behavior in sedentary animals.