Effect of Xylene Oral Exposure on the Mouse Uterus – A Preliminary Study

Abstract

Xylene is one of the environmental pollutants with a negative impact mainly on several organ systems. The aim of this study was to determine the effect of xylene on the uterus of mice. The study was performed on 12 adult female mice. Control mice (n = 6) were fed shredded pellets at a dose of 4 g per day. Xylene mice (n = 6) were fed the same diet at the same dose and orally administered xylene at 10 μl per day for 14 days. The mice were synchronized using the Whit-ten effect and introduced to males before the end of the procedure. Mice of both groups with no copulation plug were euthanized by cervical dislocation. The uteri were collected for routine histological and immunohistochemical analysis. The endometrial epithelium demonstrated vacuolar degeneration, mitotic cell activity, and the presence of leukocytes typical of metoestrus. Reductions of the endometrium, stroma, and myometrium were observed in the xylene mice. The xylene application did not have a significant effect on the superficial epithelium, or the size and number of uterine tubular glands. The immunohistochemical analysis of a proliferation marker PCNA revealed that the xylene increased its expression in the stroma, endometrial and myometrial cells, but did not significantly affect the superficial epithelial cells. The expression of an anti-apoptotic marker Bcl-xl in the xylene mice was stronger in the superficial epithelial, stromal, and endometrial cells. The Bcl-xl expression in the myometrial cells was similar to the controls. The results showed that the application of xylene stimulated the proliferation and exerted an anti-apoptotic effect on the uterine cells. However, the increased proliferation can lead to the malignant transformation of cells, resulting in their uncontrollable division.