Efeitos metabólicos e reprodutivos da sobrenutrição pós-natal precoce em ratas Wistar provenientes da redução de ninhada durante a lactação: consequências na primeira e segunda geração
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2019-04-17
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Universidade Federal de Goiás
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Nutritional and environmental insults during perinatal period induces endocrine, functional and behavioral disorders in adulthood. Thus, it is necessary to assess the impact of infant feeding on the increased risk of obesity and other associated diseases, including in subsequent generations. The objective of the present study was to evaluate the metabolic and reproductive effects of early postnatal overnutrition in Wistar during lactation and the consequences in the second generation. Female Wistar rats (F0 generation) were distributed in two experimental groups: normal litter (NL, 9 pups, n=11) and reduced litter (SL, 3 pups, n=11) throughout the lactation period. On the 3rd postnatal day (PN3), litters SL were reduced to 3 pups/dam. After weaning (PN21), F1 females (NLF1 and SLF1) were fed with water and feed at will, and metabolic and reproductive parameters were analyzed in the adult (nulliparous), pregnancy and lactation phases. In the offspring of the F1 generation (F2 generation – GCF2 and GOF2), physical and sensory-motor, metabolic and reproductive parameters. In comparison to the NLF1 group, the SLF1 generation F1 group showed: a significant increase body weight in PN7, which was maintained during the adult phase, at the end of gestation and lactation; increased food intake during PN21 to PN70, without significant difference in the pregnancy and lactation phases; increase in the fat masses in the adult, pregnancy and lactation phases; increase in the masses of the liver in the lactation phase and of the pancreas in all phases; early of the onset of puberty and lower numbers of estrus; lower performance in sexual behavior; reduction in the number of corpus luteum, with no change in pre-implantation percentage, post-implantation losses and number of live male and female fetuses; fewer live births, both male and female; greater maternal care; reduction of serum estradiol concentration; increase in serum triglyceride concentrations and reduction of HDL cholesterol in pregnancy and lactation, with no change in total cholesterol levels; increase in adult glucose. In the histopathological analyzes there was also an increase in the area of adipocytes and the thickness of the adipose layer of the mammary glands; reduction in the number of growing follicles and increase in the number of cystic and atretic follicles in ovaries; endometrial glands with inflammatory cells and degenerating in the uterus. The GOF2 offspring, compared to the GCF2 offspring, presented higher body weight from birth to PN21, as well as higher milk intake in PN8. In the evaluation of the physical and sensory-motor development, the GOF2 offspring presented advance of the sensory-motor parameters (righting reflex, negative geotaxis, cliff avoidance) in males and females. However, the auditory startle reflex was later in males and females, with no significant difference in smell and free-fall righting parameters. Regarding the physical parameters, the eruption of the incisors was anticipated and the opening of the eyes delayed, without significant difference in the unfolding of the ears. The onset of puberty was anticipated in males and females. In conclusion, early postnatal overnutrition, acting as a factor of metabolic programming, promoted obesity, metabolic and reproductive changes in F1 generation rats and, consequently, also promoted metabolic and reproductive changes and in the physical and sensory-motor development of F2 offspring.
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AMARAL, K. J. V. Efeitos metabólicos e reprodutivos da sobrenutrição pós-natal precoce em ratas Wistar provenientes da redução de ninhada durante a lactação: consequências na primeira e segunda geração. 2019. 119 f. Dissertação (Mestrado Ciências Biológicas) - Universidade Federal de Goiás, Goiânia, 2019.