Radioprotective effects of amifostine on acute and chronic esophageal injury in rodents.
Int J Radiat Oncol Biol Phys 2007;
69:534-40. [PMID:
17869666 DOI:
10.1016/j.ijrobp.2007.05.062]
[Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2006] [Revised: 04/30/2007] [Accepted: 05/25/2007] [Indexed: 11/18/2022]
Abstract
PURPOSE
This study was performed to evaluate the protective benefit of amifostine against esophageal injury from fractionated radiation in a rodent model.
METHODS
Fractionated or sham esophageal irradiation was administered to Fisher-344 rats for 5 consecutive daily fractions of 9 Gy using 150 kV X-rays. Animals received an intraperitoneal injection of amifostine or placebo 30 min before each fraction. Histopathologic analyses for mucosal thickness, submucosal collagen deposition, activation of macrophages, oxidative stress and expression/activation of integrinalphavbeta6 and transforming growth factor (TGF)-beta were performed 5 days and 10 weeks after irradiation.
RESULTS
Pre-RT mean mucosal thickness was 35 microm in both the placebo and the amifostine groups. Five days post-RT, mean mucosal thicknesses were 30 microm in the placebo group versus 37 microm in the amifostine group (p = 0.024). At 10 weeks post-RT, the group receiving amifostine experienced a significant decrease in tunica muscularis damage (p = 0.002), submucosal collagen deposition (p = 0.027), and macrophage accumulation (p = 0.026) when compared with the placebo group. The levels of immunoreactivity for oxidative stress, TGF-beta, and integrinalphavbeta6 were significantly decreased 10 weeks post-RT in the group receiving amifostine treatment compared with placebo group.
CONCLUSIONS
This study demonstrates that amifostine given before each radiation fraction protects against acute and chronic esophageal injury in a rodent model. Protection of the mucosal epithelium integrity by amifostine prevents integrinalphavbeta6 expression which reduces TGF-beta activation and subsequent development of chronic esophageal injury in this model. Further investigation is necessary to determine the clinical relevance of these findings.
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