The role of cardiovascular disease-associated iron overload in Libby amphibole-induced acute pulmonary injury and inflammation

Inhal Toxicol. 2011 Feb;23(3):129-41. doi: 10.3109/08958378.2011.551850.

Abstract

Pulmonary toxicity induced by asbestos is thought to be mediated through redox-cycling of fiber-bound and bioavailable iron (Fe). We hypothesized that Libby amphibole (LA)-induced cute lung injury will be exacerbated in rat models of cardiovascular disease (CVD)-associated Fe-overload and oxidative stress. Healthy male Wistar Kyoto (WKY), spontaneously hypertensive (SH) and SH heart failure (SHHF) rats were intratracheally instilled with 0.0, 0.25 or 1.0 mg/rat LA and examined at 1 day, 1 week or 1 month. Although histologically it was not possible to distinguish severity differences between strains in LA-induced initial inflammation and later fibrosis, quantitative assessment of biomarkers showed strain-related differences. LA-induced neutrophilic inflammation was reversible in WKY but persisted more in SH and SHHF. Lung MIP-2 mRNA increased only in WKY at 1 day in response to LA but not in SH and SHHF. Bronchoalveolar lavage fluid (BALF) protein increased in SH but not WKY at 1 week and 1 month, while γ-glutamyltransferase and N-acetyl-β-D-glucosaminidase activities increased in all strains (WKY>SH=SHHF). BALF ferritin levels were high at baseline and increased following LA exposure only in SH and SHHF. Ferritin heavy chain mRNA increased only in SHHF at 1 day. At 1 month ferritin light chain mRNA declined from already high baseline levels in SHHF but increased in WKY and SH suggesting its differential involvement in LA-induced injury in Fe-overload. Unlike WKY, both SHHF and SH failed to increase the lung lining antioxidant, ascorbate, in response to LA. We conclude that underlying CVD-associated Fe-overload is likely linked to persistent lung injury, inflammation and antioxidant decompensation following LA exposure in rats.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Asbestos, Amphibole / administration & dosage
  • Asbestos, Amphibole / toxicity*
  • Asbestosis / metabolism
  • Asbestosis / physiopathology*
  • Ascorbic Acid / metabolism
  • Biomarkers / metabolism
  • Bronchoalveolar Lavage Fluid / chemistry
  • Bronchoalveolar Lavage Fluid / cytology
  • Cardiovascular Diseases / metabolism
  • Cardiovascular Diseases / physiopathology*
  • Chemokine CXCL2 / genetics
  • Chemokine CXCL2 / metabolism
  • Dose-Response Relationship, Drug
  • Ferritins / genetics
  • Ferritins / metabolism
  • Gene Expression Regulation / drug effects
  • Iron Overload / etiology
  • Iron Overload / metabolism
  • Iron Overload / physiopathology*
  • Lung / drug effects
  • Lung / immunology
  • Lung / metabolism
  • Lung / pathology
  • Male
  • Neutrophil Infiltration / drug effects
  • Neutrophils / drug effects
  • Oxidative Stress / drug effects
  • Particulate Matter / administration & dosage
  • Particulate Matter / toxicity*
  • Pneumonia / chemically induced*
  • Pneumonia / metabolism
  • Pneumonia / physiopathology
  • RNA, Messenger / metabolism
  • Rats
  • Severity of Illness Index

Substances

  • Asbestos, Amphibole
  • Biomarkers
  • Chemokine CXCL2
  • Cxcl2 protein, rat
  • Particulate Matter
  • RNA, Messenger
  • Ferritins
  • Ascorbic Acid