Lung Injury And Fibrogenic Response To Dusts From Citrus And Grape Harvests

Abstract

Ousts were collected in citrus orchards and in vineyards from leaf surfaces in the area where harvest operations were ongoing. Six milligrams of each of the dusts was instilled intratracheally into the lungs of rats. All dusts contained approximately the same amounts of quartz. Three days later, the lung lavage fluid was assayed for protein and cell content. In animals that had been exposed to vineyard dusts, the percentage of polymorphonuclear leukocytes in the recovered cells was significantly 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 into other animals, and lung hydroxyproline content, lung lavage composition, and incorporation of bromodeoxyuridine into cellular DNA was measured 1 wk later. Following a single instillation, vineyard dust produced signs of increased cell proliferation in the large airways and terminal bronchioles and, after four instillations, was associated with an increase in total lung hydroxyproline. Citrus orchard dust showed no such effects. These data suggest that dusts generated during grape harvesting operations have fibrogenic potential, and that this might explain the presence of signs of restrictive lung disease ascertained in epidemiological studies in vineyard workers.