EFFECTS OF CEMENTED TUNGSTEN CARBIDE DUST ON RAT LUNGS FOLLOWING INTRATRACHEAL INJECTION OF SALINE SUSPENSION

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Abstract
To examine the effect of cemented tungsten carbide dust on the animal lung, saline suspensions were intratracheally administered into the lungs of rats in a single dosage. About 1/5 of the animals died during the first 3 days. The acute response of the lungs was hemorrhagic edema with intense alveolar congestion. The animals killed at 6 mo. all presented pulmonary lesions of patchy fibrosis in the vicinity of the deposited dusts, occasionally associated with focal traction emphysema and broncho-bronchiolar ectasia. At 12 mo., 2/3 of the animals had neither fibrosis nor dust deposition, although the remaining animals showed pulmonary lesions similar to those seen in the 6-mo. responders. Fibrosis of the lungs consisted of collapsed alveoli with condensation of the preexistent reticulin fibers, but without noticeable collagenization. Both the early toxic and the late fibrogenic effects of the carbide dust are evidently attributable to the cytotoxic action of Co present in the dust particles. Recovery of the pulmonary lesions may result from removal of the dusts from the lesions. Comparison to industrial worker pathologies is presented.