Modelo de hipernutrição neonatal induz sobrepeso, comportamento tipo-depressivo e aumenta os níveis séricos de il-1β na idade pré-púbere de ratos

Resumo (EN)

The growing increase in overweight and obesity is considered a global epidemic event, especial ly among children, and is regarded as one of the greatest public health challenges of the 21st century. During development, body plasticity is high and interventions during this period can have permanent effects. In this sense, diet in childhood is a factor that can modify different aspects of development. Therefore,the observation of early signs of these modifications can contribute to the knowledge of losses in later periods of life. Thus, the objective of this research was to study the effects of neonatal hypernutrition on a model of litter reduction, development, behavior,and biochemical and morphological parameters of male rats in prepubertal age. To this end, the litters of the experimental group, designated as hypernutrition group (GH) were reduced to 4 animals (3 males and 1 female) to induce hypernutrition and the control group (GC) litters were standardized with 8 animals (4 males and 4 females). During lactation, in the postnatal days (PNDs) 5 to 7, maternal behavior was evaluated. In relation to the offspring, body mass gain and physical, reflexological and motor development were observed. At weaning (PND 21), the general open field activity of the progenitors and offspring was observed and the blood of the mothers was collected to assess serum corticosterone levels and adrenocorticotrotrophic hormone (ACTH). In PND 31, the puppies were evaluated in the general open field activity, in the light-dark transition test and in the forced swimming test. At the end of the behavioral evaluations the omental, retroperitoneal and epididymal fats were removed and weighed, as well as the blood collected for assessment of cytokines, corticosterone and adrenocorticotrophic hormone (ACTH) levels. The results showed that in the progenitors of the GH group: 1) the maternal behavior related to the care of the offspring was not modified; 2) there was an increase in the time spent on self-grooming; 3) there was no change in the general activity and 4) there was no change in the serumlevels of cytokines, corticosterone and ACTH levels. In the offspring of the GH group it was observed: 1) greater weight gain in PND 21 and 31; 2) no differences in Lee's index and body mass index were observed; 3) no significant differences in physical and reflexological development; 4) regarding motor development, there was an advance in adult walking day; 5) in the general open field activity observed in PND 21,there was a increased frequency of locomotion without changes in lifting frequency and immobility duration; 6) no significant differences were observed in the general open-field activity at PND 31; 7) there was no change in behavior in the light-dark transition test; 8) lower latency for first immobility and longer immobility in the forced swimming test was observed; 9) higher weight of omental, retroperitoneal and epididymal fats; 10) increased serum levels of IL1-β, without changes in levels of IL1-α, IL-6, TNF-α; 11) reduction of corticosterone levels without changes in ACTH levels. Together, these data indicate that the neonatal hyperalimentation induced by the reduction of the litter size promoted, in the pre-pubertal age of the animals, increased adiposity and exploratory activity, signs of peripheral inflammation and depressed-type behavior.