Oral contraceptive pills: Risky or protective in case of Trichinella spiralis infection?

Summary The aim of this study was to investigate how Trichinella spiralis infection can be affected by contraceptive pills in vivo. Methods included six groups of female Wistar rats; healthy, Trichinella infected, receiving combined contraceptive pills (COCPs), receiving progestin only pills (POPs), infected receiving COCPs and infected receiving POPs. Parasite burden was measured; adult worm counts, gravidity, larvae and reproductive capacity index). Histopathological examination, immunohistochemical detection of C‐kit+ mast cells and Foxp3+ T‐reg. cells in intestinal sections, eosinophils muscle infiltration and CPK level were performed. Rats infected and receiving COCPs showed a significant increase in parasitic burden, and infected receiving POPs showed a significant reduction compared to infected only, with a significant increase in nongravid females (Mean total worms=964.40±55.9, 742±52.63, 686±31.68, larvae/g=5030±198.75, 2490±143.18 and 4126±152,91, respectively). Intestinal sections from infected receiving COCPs showed intact mucosa (though the high inflammatory cells infiltrate), and significant increase in C‐kit+ mast cells number and intensity (30.20±4.15 and 60.40±8.29), and Foxp3+ T‐reg. cells (10±1.58). Infected receiving POPs showed a significantly less CPK (5886±574.40) and eosinophilic muscle infiltration (58±13.51). Oestrogen‐containing pills established a favourable intestinal environment for Trichinella by enhancing Foxp+T‐reg. cells and stabilizing C‐kit+mast cells, while POPs gave a potential protection with less gravidity, larval burden and eosinophilic infiltrate.