A separação materna precoce prejudica o desempenho aeróbico de ratos adultos machos e fêmeas em ambiente temperado, mas não em ambiente quente, e não modifica as respostas termorregulatórias durante o exercício físico

Abstract

Rats subjected to early maternal separation exhibit behavioral and physiological impairments in adulthood, which depend on the offspring sex. These changes include a greater increase in body core temperature (TCORE) during passive heat exposure and, therefore, maternal separation may enhance the TCORE increase induced by physical exercise, impairing aerobic performance. The present study investigated thermoregulatory and performance alterations in adult male and female rats previously subjected to maternal separation. Forty-nine Wistar rats (24 males and 25 females) were divided into the following groups: maternal separation (pups were deprived from their mothers for 3 h daily for 14 days) and control. At 7 weeks of age, the pups were subjected to incremental-speed exercises to fatigue and then to 30 min constant-speed exercises. These exercises were performed in temperate (24°C) and hot (32°C) environments. As expected, the hot environment reduced the rats' performance and enhanced the TCORE increase induced by exercise, relative to the temperate environment. Rats subjected to maternal separation performed less external work during incremental exercise at 24°C, but not at 32°C. Maternal separation did not influence TCORE during the exercise protocols analyzed, regardless of environmental conditions. A secondary analysis revealed that females performed better than males at 24°C, but worse at 32°C. In general, females had higher TCORE during exercise than males. In conclusion, early maternal separation impairs the performance of adult rats in an environmental-dependent manner. Furthermore, maternal separation does not modify TCORE during exercise, suggesting that performance impairment in the temperate environment is caused by non-thermoregulatory mechanisms.