Efeitos do hipotireoidismo materno no desenvolvimento e funcionamento gastrointestinal da prole jovem de ratos Wistar

Abstract

The gestational and neonatal periods are critical periods of cell multiplication and differentiation, important for an adequate formation of organs and tissues. It is known that adverse stimuli presented to mothers can permanently alter the intrauterine environment, affecting the child health. Thus, the objective of this study was to investigate the repercussions of maternal hypothyroidism for the development and functioning of the gastrointestinal tract of the Wistar rats young offspring. For this, the pregnant rats were separated, received food ad libitum and their 30-days-old male pups divided into the groups: Control (C): mothers who received water during gestation and lactation; Experimental 1 (E1): mothers who received methimazole diluted in drinking water (0.02%) from the 8th day of gestation to the 21st day of breastfeeding; Experimental 2 (E2): mothers who received methimazole diluted in drinking water (0.02%) from the 8th day of gestation to the last day of gestation. Thyroid hormones (free T3 and T4) were measured in the lactating rats (5th day), the water and food intake determined, as well as the weight gain during pregnancy. Pups were evaluated for body weight, number of puppies, thyroid hormones (free T3 and T4) and development of the stomach and small intestine. Regarding gastrointestinal functioning, parameters such as: susceptibility to ulcers, gastrointestinal motility, intestinal fluid accumulation (enteropooling) and colonic motility were evaluated. The mothers of the E2 group gained less weight during pregnancy, but the body weight variation was not altered between the groups. The E1 group consumed less liquid, but there was no difference between the groups in the feed consumption. The mothers of the E1 group had a decrease in free T3 and T4 when compared to the mothers of groups C and E2. There was no difference between groups in the number of pups. T3 levels were not different and T4 levels were lower in E1. Body weight and stomach area were lower in pups of experimental groups, stomach weight and ulcer susceptibility were lower in E1. The length of the small intestine was not altered, but its weight was lower in E1 and E2, as well as the motility of this organ in E2. Enteropooling was higher in the animals of groups C and E1 that received castor oil than those that received saline, whereas the E2 group, which received castor oil, presented lower enteropooling compared to groups C and E1, in the same groups conditions. Finally, the distal colon motility was not altered. It is concluded that maternal hypothyroidism affects the body growth as well as the development of the stomach and small intestine of the offspring, but it interferes in a different way in the operation of the gastrointestinal tract of the pups, depending on the period of induction.