EFFECTS OF EXPOSURE TO BOTULINUM TOXIN TYPE A DURING PREGNANCY ON MATERNAL CARE AND REPRODUCTIVE PERFORMANCE IN RATS

Botulinum toxin type A (BT-A) is a neurotoxin that blocks the release of acetylcholine from cholinergic nerve terminals and, therefore, is indicated for the treatment of disorders such as movement disorders. However, due to the lack of studies on gestational exposure, its use during this period is not recommended, leading women to interrupt chronic treatments. The rat as an animal model for toxicity studies may contribute to the identification of neurotoxicity. Thus, this study aims to evaluate the possible effects of gestational exposure to BT-A on maternal care. For this purpose, female Wistar rats received a single dose of BT-A (4, 8, or 16 U/kg) or saline solution (0.9% NaCl) (n=8 animals/group), administered intramuscularly on gestational day (GD5). Evaluations were performed using the nest-building test, reproductive performance, maternal behavior, and aggressive maternal behavior. Considering that maternal behavior begins before the birth of the pups, the nest-building test showed no alteration in this parameter before birth, and reproductive performance indicated that the litters were born equally healthy (body weight and number of pups). The results of the maternal behavior and aggressive maternal behavior tests, conducted on lactation days (LD) 5 and 6, respectively, showed that exposure to BT-A did not alter any parameter related to the expression of direct and indirect maternal care. Thus, despite the toxic effects and the known interference of BT-A with the cholinergic system, its administration at the beginning of lactation did not interfere with any component of maternal care nor cause maternal toxicity.