Genetic deficiency of alpha1-PI in mice influences lung responses to bleomycin

It has recently been suggested that proteinase inhibitors modulate the fibrotic response in the lung. This study investigated the development of bleomycin-induced pulmonary changes in pallid mice, deficient in serum α1‐proteinase inhibitor, and with a lower elastase inhibitory capacity, and in congenic C57Bl/6J mice.Male pallid and C57Bl/6J mice received a single intratracheal instillation of either saline or bleomycin. The investigation was carried out by means of biochemical, morphological and morphometrical methods.In both strains, 21 and 72 h after bleomycin, the lungs showed foci of inflammatory cell infiltration associated with emphysema. Fibrosis developed with time after bleomycin. At 14 days fibrosis affected 23.46±9.48% (mean± sd) and 40.62±13.34% (pThus, the lung destructive response (emphysema) and the subsequent proliferative reaction (fibrosis) to bleomycin are potentiated in α1‐proteinase inhibitor deficiency.