Effect of quartz dust on the lungs of mice.

Intratracheal inoculations of quartz dust (250 mg/kg body weight) of a particle size less than 5 mum were given in mice and pulmonary tissue reactions studied over a period of 210 days. Acute inflammatory reaction in the lung parenchyma was observed at early periods and later the aggregates of dust laden macrophages encountered around bronchi and blood vessels. Towards the termination of the experiment at 210 days the fibrotic reaction comprised chiefly of thick compactly arranged reticulin fibers with few collagen fibers which remained restricted to the peribronchial and perivascular areas. There was no silicotic nodule formation in the parenchyma of the lung. The atypical pulmonary tissue response to quartz dust in mice has been attributed to different tissue reactivity.