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Early biochemical reactions in the lung of sheep exposed to asbestos: Evidence for cyclic AMP accumulation in bronchoalveolar lavage fluids

Research paper by I. Lemaire, P. Sirois, M. Rola-Pleszczynski, S. Massé, R. Bégin

Indexed on: 01 Dec '81Published on: 01 Dec '81Published in: Lung



Abstract

A conscious sheep model which allows sequential analysis of the bronchoalveolar milieu was used to investigate the early biochemical events following asbestos exposure. Segmental bronchoalveolar lavages (BAL) were performed in a group of 15 sheep exposed to repeated doses of UICC chrysotile B asbestos (0–128 mg) over a six month period. BAL cell population was analysed and various humoral components including total proteins, albumin, alpha1-globulins (α1), alpha2-globulins (α2), beta + gamma globulins (β+γ) and adenosine 3′,5′-cyclic monophosphate (cAMP) were determined in cell free supernates. All animals were also studied by pulmonary function tests (PF) and transbronchial lung biopsies (LB). Exposure to asbestos (up to 128 mg/month) did not cause any significant alteration of pulmonary functions and lung histology. However, analyses of the BAL effluent revealed that BAL fluids of sheep exposed to asbestos contained higher levels ofα1-globulins and cyclic AMP as compared to controls. Furthermore this phenomenon was observed without overall change of BAL cell population except for a significant eosinophilia in the asbestos-exposed animals. These data demonstrate that the early biochemical response of sheep exposed to asbestos is characterized by a significant eosinophilia and increases ofα1-globulins and cyclic AMP in the bronchoalveolar milieu. These biochemical events may be involved in the chronic inflammatory reaction to asbestos and possibly in the fibrogenic response.