LUNG INJURY AND FIBROGENIC RESPONSE TO DUSTS FROM CITRUS AND GRAPE HARVESTS

Dusts were collected in citrus orchards and in vineyards from leaf sur faces in the area where harvest operations were ongoing. Six milligram s of each of the dusts was instilled intratracheally into the lungs of rats. All dusts contained approximately the same amounts of quartz. T hree days later, the lung lavage fluid was assayed for protein and cel l content. In animals that had been exposed to vineyard dusts, the per centage of polymorphonuclear leukocytes in the recovered cells was sig nificantly higher than in control animals. This change was not seen in animals exposed to citrus orchard dusts. One of the vineyard and one of the citrus orchard dusts were instilled either once or four times i nto other animals, and lung hydroxyproline content, lung lavage compos ition, and incorporation of bromodeoxyuridine into cellular DNA was me asure 1 wk later. Following a single instillation, vineyard dust produ ced signs of increased cell proliferation in the large airways and ter minal bronchioles and, after four installations, was associated with a n increase in total lung hydroxyproline. Citrus orchard dust showed no such effects. These data suggest that dusts generated during grape ha rvesting operations have fibrogenic potential, and that this might exp lain the presence of signs of restrictive lung disease ascertained in epidemiological studies in vineyard workers.