N-ACETYL-BETA-D-GLUCOSAMINIDASE ACTIVITY WITHIN BAL FROM MACAQUES EXPOSED TO GENERIC COAL DUSTS

N-acetyl-beta(beta)-D-glucosaminidase is a lysosomal enzyme secreted b y alveolar macrophages in response to phagocytosis of particulate mate rial. Alveolar macrophages participate in the degradation and fibrosis of pulmonary tissue that results in pneumoconiosis. Known quantities of four characterized respirable dusts were bronchoscopically placed i nto the right caudal lung lobe of macaque monkeys. Bronchoalveolar lav age (BAL) samples were collected from dust-exposed right lung and unex posed left lung of the same individuals at 2-week intervals for 12 wee ks after dust instillation. The samples were tested for N-acetyl-beta- D-glucosaminidase activity to determine if the enzyme levels could ser ve as an indicator of pulmonary injury induced by generic coal dusts w hen compared to known fibrogenic and nuisance dusts. Installation of g eneric quartz, anthracite, or TiO2 dusts produced significant elevatio ns of enzyme activity and increased numbers of macrophages in the dust -exposed lobes. Elevations in enzymatic activity and macrophage number s were greatest in response to generic quartz dust. These results sugg est that quantitative levels of N-acetyl-beta-D-glucosaminidase activi ty may be a useful indicator of acute and chronic lung injury followin g exposure to fibrogenic and nonfibrogenic dusts.