A. Francois et al., Modified absorptive and secretory processes in the rat distal colon after neutron irradiation: In vivo and in vitro studies, RADIAT RES, 151(4), 1999, pp. 468-478
Impaired fluid and electrolyte transport in the intestine is a well-recogni
zed characteristic of radiation-induced pathologies in the gastrointestinal
tract. The aim of this study was to investigate the responsiveness of the
epithelium of the colon of the rat to electrical and pharmacological (serot
onin, carbachol) stimulation concomitantly with in vivo assessment of the a
bsorptive capacity of the colon at 1, 3, 5 and 7 days after 3.8 Gy whole-bo
dy exposure to neutrons, The responsiveness of rat colon in vitro to electr
ical stimulation and the number of mast cells were measured to examine the
role of neuroimmune networks in radiation-induced dysfunction, Animals show
ed an impaired capacity of the colon to absorb water and sodium from 3 to 5
days after irradiation together with decreased responsiveness to electrica
l and pharmacological stimulation. The time course of decreased responsiven
ess to neural stimulation was similar to that of impaired absorption observ
ed in vivo, but it was not correlated with variations in mast cell numbers,
Histological (mast cells) and biochemical analyses (myeloperoxidase and NO
synthase activities) did not find evidence of a marked infiltration and/or
activation of inflammatory cells. Thus the impaired absorptive capacity of
the colon observed after irradiation occurs concomitantly with decreased n
eural influence, and is possibly related to reduced epithelial functional c
apacity but not to decreased mast cell numbers. (C) 1999 by Radiation Resea
rch Society