Histological demonstration of changes in connective tissue components in uterine tissue undergoing decidualization on days 4th, 5th, and 8th days of mouse pregnancy

Abstract

This study examined the changes in connective tissue elements of the uterine undergoing decidualization on the 4th, 5th, and 8th days of pregnancy by histochemical methods. The study divided 6-8 weeks-old Balb/c mice into four groups non-pregnant estrous phase, 4th, 5th, and 8th-day pregnancy models. 5µm thick sections were taken from paraffin blocks obtained from uterine tissues. Samples were stained with Hematoxylin&Eosin, Mallory Azan, Orsein, and Periodic Acid Schiff stains. As a result of the staining, the uterine tissue in the non-pregnant estrus phase showed standard histological structure. On the 4th day of pregnancy, the amount of intensely stained collagen and elastic fiber decreased on the 5th day of gestation; On the 8th day of pregnancy, it was determined that the density of the fibers increased again. As a result, both increased collagen and elastic fibers for its placement to an elastic-solid uterine tissue and increased carbohydrates for its nutrient needs and immune privilege were demonstrated in the uterus for the 4th-day embryo. The decrease in connective tissue elements with the acceleration of decidualization on the 5th and increased collagen and elastic fibers in the myometrium and the PAS + NK cells in the endometrium on the 8th-day was noted.