The effect of indomethacin, prednisolone and cis-4-hydroxyproline on pulmonary fibrosis produced by butylated hydroxytoluene and oxygen.

The purpose of this study was to examine whether development of pulmonary fibrosis in mice could be influenced by indomethacin, prednisolone or a proline analog. Pulmonary fibrosis was produced in mice treated with butylated hydroxytoluene (BHT) 400 mg/kg and immediately exposed to 80% oxygen for 3 days. This treatment regimen resulted in 47% mortality. Surviving mice exhibited significant accumulations of pulmonary collagen as evidenced by increases in total lung hydroxyproline levels. The administration of indomethacin (4 mg/kg/day) on days 1-6 after BHT decreased mortality to 14% and diminished the accumulation of collagen in lung tissue. Indomethacin also enhanced survival when administered on days 1-3 after BHT/O2 but had no effect on lung collagen levels. Treatment with indomethacin on days 4-6 after BHT had no beneficial effect. The administration of prednisolone (60 mg/kg/day) on days 1-3, 1-6, or 4-6 after BHT decreased mortality but had no effect on accumulation of lung collagen. Cis-4-hydroxyproline (400 mg/kg/day) also had no effect on pulmonary fibrosis but did enhance survival when given on days 1-3 after BHT. Administering prednisolone (60 mg/kg/day) on days 1-6 after BHT to mice left in room air produced significantly more pulmonary fibrosis than in BHT-treated mice given saline. These data support the use of the BHT/O2 model of pulmonary fibrosis for screening potential antifibrotic agents. The possibility that corticosteroid treatment may enhance pulmonary fibrosis in a damaged lung is also demonstrated.