Effect of Infection with Taenia Pisiformis on Immune Cells Recruitment and Uterine Mucosa Histomorphometry of...

Taenia pisiformis cysticerci have been reported in the female reproductive tract of rabbits, and this parasitosis is known to alter reproductive behavior and reduce embryo implantation; however, tissue-based studies relating the immune system to the implantation site during infection have not been previously addressed. Therefore, our research provides new information on the interaction between pregnancy and parasitic infection.

This study evaluated the recruitment of immune cells in uterine tissue during T. pisiformis infection. Fourteen female rabbits were experimentally infected with 1,000 T. pisiformis eggs and mated with a male on day 50 post-infection. Eight days after mating-corresponding to the mesometrial stage of implantation- tissue samples were collected from the middle third of the right uterine horn at the site of embryonic implantation, following the sampling rationale described in previous literature. Samples were fixed and processed using paraffin-embedding techniques, and histological sections were stained with hematoxylin and eosin. Three sections per rabbit were analyzed across 18 fields per group, each field measuring 2,960 μm². Mucosal height was measured, and lymphocytes and macrophages were quantified in the mucosa based on morphological criteria.

The results showed a significant increase in lymphocyte and macrophage infiltration at the implantation sites of infected does compared to controls (p < 0.05), along with a 49% increase in mucosal height. No cysticerci were found in the uterine tissue, but metacestodes were observed in the pelvic region in 33% of infected animals, with a mean of 3.1 ± 2.6 cysticerci per animal.

These findings suggest an increased immune cell infiltration and marked uterine mucosal remodeling in infected does, potentially interfering with embryo establishment and development. We acknowledge that hormonal and cytokine measurements were not performed in this study; therefore, future research should address these parameters to clarify the underlying mechanisms.