Taenia taeniaeformis larval product induces gastric mucosal hyperplasia in SCID mice

The effects of intraperitoneal implantation of Taenia taeniaeformis larvae and inoculation of in vitro larval products on gastric mucosa of SCID mice were investigated in this study. Mice surgically implanted with T. taeniaeformis larvae developed slight and moderate gastric hyperplasia. When in vitro cultured T. taeniaeformis larval excretory-secretory (TtLES) products containing 1 mg of protein were injected daily into mice, they caused gastropathy after 5-7 days. Mice injected daily with 0.5 mg of TtLES products also showed slight gastric hyperplasia after day 14 and 28. The gastropathy was characterized by reduction of both parietal and zymogenic cell number and increased number of alcian blue-periodic acid Schiff (AB-PAS)-positive cells and by two-fold extension of proliferative zone of gastric units. Larval implantation demonstrated a more potent effect in inducing gastropathy than did in vitro larval culture products. Significant decrease in number of parietal cells with concomitant increase of proliferative zone and AB-PAS-positive cell number indicated their important roles in inducing the hyperplastic lesion. Similarities with other gastropathies indicated that there is a common fundamental regulatory mechanism involved, and that the host response may not be specific to parasites. Present study validated the induction of gastric mucosal hyperplasia by larval ES products of T. taeniaeformis. This proved the hypothesis of previous studies suggesting the role of larvae-derived products in inducing gastric mucosal hyperplasia in T. taeniaeformis-infected rats.