Influência do hipotireoidismo gestacional experimental sobre o comportamento materno e sua repercussão na prole

Abstract

The thyroid hormones act in almost all systems during development and throughout postnatal life however the hypothyroidism is an endocrine disease that affects pregnant women. Anoth-er important factor to be considered, which is involved with the cognitive and emotional de-velopment of the offspring, is the maternal care. Thus, the objective of this work was to eval-uate the effect of gestational experimental hypothyroidism on the maternal behavior and its consequences on the offspring. For this, Wistar rats were treated with methimazole (MMI) 0.02% in drinking water from the 9th day of pregnancy until the day of delivery. The maternal behavior (MB) was recorded daily from 2nd day until the 21st day of lactation, moreover was rated the MB of fostering group, which consisted of adoptive mothers treated with water with biological offspring of mothers treated with MMI. There was still physical development anal-ysis and reflection of the puppies of mothers treated with MMI and control. The offspring from the MB were also used to record the body weight and, when adult, to behavioral analysis in elevated plus maze, open-field and fear conditioning to context. The results showed that there was an increase in the maternal behavior with relevance, especially in puppies licking behavior and a reduction of the total non-maternal behavior in mothers treated with methima-zole. Such behavioral profile was also observed in fostering group. In relation to the body weight, offspring of mothers treated with methimazole showed a reduced birth weight com-pared with offspring of control mothers. In the analysis of the development there was a delay mainly in reflexes righting, geotaxis negative, palmar grasp and auditory startle in males as in females of the offspring of MMI-treated mothers. In the elevated plus maze test males of mothers treated with methimazole showed a lower frequency of entries in open arms, and have had less time on them. In this way, we can infer that stimuli to the increase maternal be-havior displayed by the mothers treated with methimazole and mothers of fostering group is the need of the puppies by more maternal care due to deleterious effects suffered by them in the uterus. Such purposes shall be associated with development delays displayed by the off-spring of mothers treated with methimazole and anxiety-related behavior in elevated plus maze displayed by males when in adulthood.