Activity of Brush Border Membrane Bound Enzymes in the Small Intestine of Mice Infected with Fibricola seoulensis

Abstract

Fibricola seoulensis is a trematode of the human intestine inducing severe atrophy of the villi. Human cases suffer from severe diarrhea, abdominal discomfort and fever. The heavily infected mice died mainly because of dehydration and luminal bleeding. The atrophic change of the intestinal mucosa is suspected to be related to functional derangements. The present study intended to observe the changing activity of the brush border membrane bound enzymes in the intestines of infected mice. Each mouse was infected with 100 or 1000 metacercariae collected from snakes. The mice were sacrificed chronologically after infection, and after praziquantel treatment. The mucosa of their intestines (duodenum, proximal jejunum and distal jejunum) was collected and homogenized. The protein content and enzymatic activity of the homogenates were measured. The activity of sucrase, lactase, trehalase, alkaline phosphatase and leucine aminopeptidase in the intestinal mucosa increased just after infection and began to decrease after 1 week to 32 days. Decreased activity recovered distinctively 20 days after treatment. The activity of all the enzymes increased in the distal jejunum. In mice infected with 1000 metacercariae, the activity changed in a similar pattern to those with 100 metacercariae. The findings suggest that the infection of F. seoulensis disturbs final digestion and absorption on the brush border membrane eventually causing osmotic diarrhea. Such effects were recovered after treatment with praziquantel.