371. Radiat Res. 1996 Jun;145(6):762-7.
Early and persistent alterations in the expression of interleukin-1 alpha,
interleukin-1 beta and tumor necrosis factor alpha mRNA levels in
fibrosis-resistant and sensitive mice after thoracic irradiation.
Johnston CJ(1), Piedboeuf B, Rubin P, Williams JP, Baggs R, Finkelstein JN.
Author information:
(1)Department of Pediatrics, University of Rochester School of Medicine and
Dentistry, New York 14642-8777, USA.
Fibrosis, characterized by the accumulation of collagen, is a consequence of a
chronic inflammatory response. The purpose of this study was to determine if
tumor necrosis factor alpha (TNF-alpha), interleukin-1 alpha (IL-1 alpha) and
IL-1 beta mRNA expression are altered acutely after irradiation, during the
so-called "latent" phase of pulmonary injury, and to examine if these alterations
persist through the development of pneumonitis and fibrosis. Further, we wished
to determine if these changes differ between two strains of mice which vary in
their sensitivity to radiation. Fibrosis-sensitive (C57BL/6) and
fibrosis-resistant (C3H/HeJ) mice were irradiated with a single dose of 5 or 12.5
Gy to the thorax. Total lung RNA was prepared and immobilized by slot blotting
and hybridized with radiolabeled cDNA probes encoding for TNF-alpha, IL-1 alpha
and IL-1 beta. Autoradiographic data were quantified by video densitometry and
results normalized to a control probe encoding for glyceraldehyde-3-phosphate
dehydrogenase. It was found that TNF-alpha mRNA levels were increased in C57BL/6
mice at days 1 and 7 postirradiation after 5 Gy and day 14 postirradiation after
both 5 and 12.5 Gy, and IL-1 alpha mRNA levels were increased in C57BL/6 mice at
days 56, 112 and 182 postirradiation after both 5 and 12.5 Gy, and IL-1 beta mRNA
levels in the C3H/HeJ mice were increased at days 56 and 182 postirradiation
after 12.5 Gy. In summary, these studies demonstrated early and persistent
alterations in TNF-alpha, IL-1 alpha and IL-1 beta mRNA levels even at the lower
dose (5 Gy). The temporal relationship between the elevation of these cytokines
and the strain-dependent variation in fibrosis response suggests that IL-1 alpha
and TNF-alpha contribute to the radiation-induced component of pulmonary
fibrosis, whereas IL-1 beta may have a protective function.
PMID: 8643837 [PubMed - indexed for MEDLINE]