302. Exp Lung Res. 2002 Oct-Nov;28(7):577-90.
Assessment of the protective effect of amifostine on radiation-induced pulmonary
toxicity.
Vujaskovic Z(1), Feng QF, Rabbani ZN, Samulski TV, Anscher MS, Brizel DM.
Author information:
(1)Department of Radiation Oncology, Duke University Medical Center, Durham,
North Carolina 27710, USA. vujas@radonc.duke.edu
The objective of this study was to assess the radioprotective effects of
amifostine in the rat model of radiation-induced lung injury using fractionated
doses of radiation, to determine whether amifostine given before irradiation
protects tumor from radiation cytotoxicity, and to determine whether changes in
plasma levels of transforming growth factor (TGF)-beta correlate with
radioprotective effect of amifostine. R3230 AC mammary adenocarcinoma was
transplanted on the right posterior chest wall of female Fisher-344 rats. Both
tumor-bearing and non-tumor-bearing animals were irradiated to the tumor or right
lung using 4 MV photons and fractionated dose of 35 Gy/5 fractions/5 days.
Animals with tumors and those without were randomized into 4 groups, respectively
(8 to 10 rats per group), to receive (1) radiation alone; (2) radiation +
amifostine; (3) amifostine alone; (4) sham radiation. Amifostine (150 mg/kg) was
given intraperitoneally 30 minutes before each fraction of irradiation. The tumor
size was measured twice a week. Breathing rate was assessed every 2 weeks.
TGF-beta levels in plasma were assessed monthly after treatment. Six months after
irradiation, animals were euthanized and lung tissue was processed for
hydroxyproline content analysis. A significant increase in breathing frequency
started 9 weeks after irradiation in animals that received radiation only. In the
radiation + amifostine group, there was both a delay and a significantly lower
peak in breathing frequency (P < .001). Hydroxyproline content was higher in the
radiation-alone group than in rats given amifostine prior to radiation (P < .05).
The TGF-beta levels in plasma showed an increase from 1 to 3 months after
radiation, peaking at 2 months in the rats with (2.80 +/- 0.23) or without (5.32
+/- 1.21) amifostine compared to sham irradiation. TGF-beta levels were
significantly lower at 1 to 3 months in rats receiving amifostine plus radiation
versus those receiving radiation alone. Tumor growth delay and regrowth rate
after radiation were not different between radiation-alone and radiation +
amifostine groups. This study confirms the protective effect of amifostine in
reducing radiation-induced pulmonary toxicity. No tumor protection was
demonstrated after fractionated radiotherapy. The reduction in pulmonary injury
with amifostine in paralleling lower plasma levels of TGF-beta, suggesting that
monitoring plasma levels of this cytokine may reflect the efficacy of an
intervention aimed at preventing radiation-induced lung injury.
PMID: 12396250 [PubMed - indexed for MEDLINE]