Increased intestinal muscle contractility and worm expulsion in
nematode-infected mice.
Vallance, Bruce A., Patricia A. Blennerhassett, and Stephen M.
Collins.
Intestinal Diseases Research Programme, McMaster University,
Hamilton, Ontario, Canada
APStracts 3:0207G, 1996.
Intestinal nematode infections are accompanied by mucosal inflammation
and an increase in propulsive motor activity that may contribute to
parasite eviction from the gut. To examine whether differences in
worm expulsion correspond to the increased intestinal muscle
contractility that accompanies nematode infection, we studied mice
with genetically-determined differences in their ability to expel the
nematode parasite Trichinella spiralis. Specifically, we examined
isometric contraction of longitudinal muscle, worm counts and
inflammation, as measured by myeloperoxidase (MPO) activity, in two
strains of mice infected with T. spiralis. The strong responder
strain, NIH Swiss, expelled the parasites by day 16 P.I., while the
poorer responding B10.BR strain was still heavily infected by day 21
P.I. However, both strains developed similar increases in jejunal MPO
activity. Both strains demonstrated increased isometric tension
development following infection, but peak tension occurred earlier in
NIH Swiss mice (day 8 vs day 12 P.I.) and was of significantly
greater magnitude than in the B10.BR mice. We conclude that the
ability to expel T.spiralis from the small bowel is not related to
the degree of granulocyte dependent mucosal inflammation, but is
reflected in the magnitude of the accompanying increase in force
generation by intestinal smooth muscle.
Received 27 November 1995; accepted in final form 26 August 1996.
APS Manuscript Number G499-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 5 November 1996