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INFLAMMATION/IMMUNITY/MEDIATORS
B in rat ileal muscularis layer
Institute for Radioprotection and Nuclear Safety, Human Health Protection and Dosimetry Division, Independent Section of Radiobiology Applied to Medecine, F-92262 Fontenay-aux-Roses Cedex, France
Submitted 24 February 2003 ; accepted in final form 28 May 2003
The small bowel is an important dose-limiting organ in abdominal
radiotherapy because irradiation can cause acute enteritis that, in turn,
leads to progressively reduced motility and finally, in a later phase, to
fibrosis. Because these clinical symptoms may be caused by the early stage of
an inflammatory process, we characterized the radiation-induced intestinal
inflammation in rats. Abdominal
-irradiation (10-Gy) induced a cascade
of inflammatory events characterized by an early (6 h after exposure) increase
in IL-1
, TNF-
, and IL-6 mRNA levels in the rat ileal muscularis
layer. IL-8 [a cytokine-induced neutrophil chemoattractant (CINC)] mRNA
appeared later (at 3 days). The expression of TGF-
(a profibrotic
cytokine) was higher in irradiated than control tissue at day 1,
whereas IL-10 (an anti-inflammatory cytokine) expression vanished completely.
Despite strong IL-1ra expression, the IL-1ra/IL-1
ratio, which is an
indicator of inflammatory balance, was -41% at day 1 in irradiated
compared with control tissue. The nuclear transcription factors NF-
B
and activator protein-1 (AP-1) govern transcription of these genes, directly
or indirectly. Although expression of the subunits of NF-
B (p65, p50)
and AP-1 (c-fos, c-jun) did not increase, irradiation caused
a rapid and persistent translocation of p65 and p50. An imbalance between
proinflammatory and anti-inflammatory mediators may contribute to perpetuating
intestinal inflammation, thus making it chronic.
intestine; inflammation; p65 and p50; c-jun and c-fos
This article has been cited by other articles:
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P Gourmelon, C Marquette, D Agay, J Mathieu, and D Clarencon Involvement of the central nervous system in radiation-induced multi-organ dysfunction and/or failure Br. J. Radiol., January 1, 2005; Supplement_27(1): 62 - 68. [Abstract] [Full Text] [PDF] |
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