Stereological study of parenchyma and stroma cells of the small intestine of prepubertal rats under heavy metal exposure

Small intestinal epithelial cells of small rodents can be a good model for studying chronic toxic effects. Studies on prepubertal animals are particularly relevant, as they can help in assessing the technogenic environmental impact on adolescents. The aim of the study is to conduct a stereological analysis of parenchyma and stroma cells of the small intestine of prepubertal rats under chronic heavy metal exposure in subtoxic doses. Materials and Methods. For 21 days 4-week-old male Wistar rats were given subtoxic doses of Cd (Group 2), Pb (Group 3), or their combination (Group 4) per os. Paraffin and ultrathin sections of the small intestinal mucosa were examined using the stereological method and Image J 1.7 software. The Mann-Whitney U test with Bonferroni correction was used for statistical processing of the results. The Kruskal-Wallis test was used to test the median equality of three or more independent samples. Results and Discussion. Stereological study of parenchyma and stroma cells of the small intestinal mucosa under chronic subtoxic influence of Cd and Pb salts demonstrated multidirectional changes in the volume density of light and dark enterocytes, visually noticeable increase in intercellular space, and the increase in volume density of goblet cells under combined influence. Biosynthetic compartment of enterocytes (nucleoli, endoplasmic reticulum and mitochondria) in experimental groups of rats was statistically significantly reduced compared to the control. Conclusion. The study revealed the reactivity of immune system cells with an increase in the volume density of lymphocytes and its decrease in plasma cells in experimental groups 3 and 4 (under Pb exposure), and a pronounced trend towards the parameter increment in matrix-producing cells.