[Effect of 764-3 on histamine content in the lungs during inflammation and on the proliferation of lung fibroblasts].

The changes of histamine content in inflamed lungs induced by bleomycin, lung fibroblast proliferation enhanced by histamine and the effect of 764-3 on these parameters were investigated. Results showed that: 1) after intratracheal instillation of bleomycin for 7 and 21 days, the lung histamine content increased significantly, and 764-3 inhibited this increase of histamine content; 2) histamine enhanced the proliferation of lung fibroblasts in a dose- and time-dependent manner, and 764-3 inhibited the proliferation of lung fibroblasts in both normal and histamine-enhanced conditions. Results suggested that both inhibitory actions (direct inhibition of fibroblast proliferation and indirect action stemming from a reduction in the histamine content increase) might be involved in the antifibrotic mechanism of 764-3.