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Deferoxamine infusion does not inhibit bleomycin-induced lung damage in the rat
H E Ward1, M Hicks, A Nicholson
1Department of Medicine, University of Sydney, Australia.
Abstract:
It has been proposed that the pneumonitis and subsequent lung fibrosis induced by bleomycin occurs when bleomycin is complexed with ferrous iron and oxygen. In order to see whether chelation of free iron reduced tissue damage induced by intratracheal bleomycin, deferoxamine (DFO) was administered by continuous subcutaneous infusion to overcome its rapid renal excretion. Thirty-three rats received DFO and 30 rats received an equivalent volume of saline by 7-day infusion pumps. Three days after commencement of infusion, half of each group received intratracheal bleomycin, the remainder received intratracheal saline. Three weeks after intratracheal injection, the rats were killed and their lungs were removed for histologic and morphometric assessment and collagen estimation. When compared with animals given intratracheal saline, both bleomycin-treated groups had significant evidence of lung toxicity, but DFO was not protective. Similarly, DFO infusion did not reduce the elevation in collagen concentration (bleomycin/saline, 49 +/- 3.6; bleomycin/DFO, 49.8 +/- 4.1; saline/saline, 39.6 +/- 3.9; saline/DFO, 43.4 +/- 3.8 mg.g-1 wet lung weight) or total lung collagen (bleomycin/saline, 29.9 +/- 6.3; bleomycin/DFO, 33.7 +/- 1.8; saline/saline, 15.5 +/- 2.2; saline/DFO, 17.8 +/- 1.9 mg.left lung-1) induced by bleomycin. This lack of effect was not due to iron contamination of the DFO in the pump or to loss of chelation capacity of DFO, at least for as long as 6 days after pump implantation. No DFO was detected in homogenized lung tissue (limits of detection of assay was 8 x 10(-5) M).(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Deferoxamine (DFO) did not protect against bleomycin-induced lung fibrosis in rats. Iron chelation therapy did not reduce lung toxicity or collagen levels following bleomycin exposure.
Area of Science:
- Pharmacology
- Toxicology
- Pulmonary Medicine
Background:
- Bleomycin-induced lung injury is a significant concern, potentially linked to iron-bleomycin interactions.
- Iron chelation therapy is explored as a protective strategy against bleomycin toxicity.
Purpose of the Study:
- To investigate if deferoxamine (DFO), an iron chelator, can mitigate bleomycin-induced pneumonitis and lung fibrosis.
- To assess the impact of iron chelation on histological and biochemical markers of lung damage.
Main Methods:
- Rats received continuous subcutaneous infusion of deferoxamine (DFO) or saline for 7 days.
- Intratracheal bleomycin or saline was administered to half of each group.
- Lungs were analyzed for histology, morphometry, and collagen content three weeks post-bleomycin administration.
Main Results:
- Bleomycin treatment led to significant lung toxicity in both DFO and saline groups.
- DFO administration did not reduce the histological evidence of lung damage.
- Elevated collagen concentration and total lung collagen induced by bleomycin were not affected by DFO treatment.
Conclusions:
- Deferoxamine (DFO) failed to protect against bleomycin-induced lung toxicity and fibrosis in this rat model.
- Iron chelation via DFO does not appear to be a viable therapeutic strategy for preventing bleomycin lung injury.
- Further research is needed to elucidate the role of iron in bleomycin-induced lung damage.