Relationship of jute dust to interstitial fibrosis in rat lung

The relationship between jute dust and lung interstitial fibrosis was studied by instilling groups of rats, via trachea, with jute dust and comparing the results with those for positive (quartz) and negative (saline) controls. The rats were sacrificed at regular intervals and their lungs and hilar lymph nodes were analyzed for collagen content and morphologic changes. The earliest changes consisted of alveolar edema, increased numbers of intraalveolar macrophages, and marked thickening of the interalveolar septa, with mixed cellular infiltrates. Moderate thickening of the alveolar walls and the zones around the peribronchioles was seen in the test groups at 6 mo. After 12 mo, some fibrosis of the alveoli walls and peribronchiole zones occurred. Interstitial cellular nodules were observed occasionally, composed mainly of dust particles, fibroblasts, reticular fibers, and collagen fibers. The collagen content in the lungs of the jute dust groups was significantly higher than for the saline control group for all test periods. The authors conclude that jute dust may induce lung interstitial fibrosis.