The occupation of intestinal epithelium by Trichinella spiralis in BALB/C mice is not associated with local manifestation of apoptosis related factors

Trichinella spiralis actively passes through the epithelial cells of the intestinal mucosa but morphologically, these cells do not manifest apparent damage. The possible activation of apoptotic mechanisms in the small intestine mucosa after infection with larvae and adults of Trichinella spiralis was explored by immunohistochemistry. Sporadic individual cells of normal intestinal epithelium showed activation of caspase-3, increased expression AIF, or Bax. The larval stage of intestinal trichinellosis was characterized by distortion of cells on the villus tips that were strongly reactive to caspase-3, Bax, and survivin antibodies. There was a transient loss of the survivin expression on the brush border of the epithelial cells at 15-h post infection, which reappeared on the fifth day. Bcl-2 changed its normal apical distribution and re-localized to the basal part of the epithelial cells. No significant changes of expression of the selected apoptosis-related proteins were observed in the intestinal epithelial cells immediately surrounding the worms. The presence of Trichinella affects intestinal epithelial cells, but unlike in muscle cells, invading them does not initiate apoptotic factors activation.