Some features of the brain of Wistar rats that developed in broods of various numbers

Abstract

Objective: To study the morphofunctional features of the brain development of 14- and 30-day-old rats born in broods that differ significantly in numbers.Methods: 2 age groups of animals were studies – 14-day-old and 30-day-old rat pups, the offspring of intact rats, each group was divided into subgroups: 1) small broods (4-7 rat pups per brood) and 2) broods of average size (9-12 rats in a brood). The brains of animals of both subgroups were subjected to morphometric and histochemical studies. At the age of 28 days, rat pups from the second age group were tested in an elevated plus maze.Results: It was found that rat pups from small broods at the age of 14 and 30 days had signs of acceleration and differed in the outstripping rates of development of brain from animals from the group of broods of average size. Differences were manifested by a greater mass of the brain and hemisphere, a lower numerical density of neurons and a higher density of gliocytes, a large glioneural index, as well as the size of neurons, their nuclei and nucleoli in the cortex of the parietal lobe and the hippocampus. The behavior of pups from small broods and broods of average numbers at the age of 28 days in an elevated plus maze had significant intergroup differences.Conclusions: These findings indicate that differences in brood numbers affect important indicators of brain development.