Animal study of silicosis in respect of morbidity and mortality.

ABSTRACT

Silica activates release of biochemical substances in lungs. To evaluate duration dependent toxic effects of silica by biochemical changes in Broncho Alveolar Lavage Fluid (BALF) and by post-mortem findings we developed a series of rat silicosis. Based on duration of exposures, single intratracheal injection of quartz dust in saline to acute models (n=3) and inhalation of quartz dust with air to chronic models (n=3) were administered. Control rats received vehicle only. Group wise BALF was collected on completion of exposure periods. Post-mortem examination was performed. Protein, hydroxyproline, elastase and Elastase Inhibitory Capacity (EIC) in BALF were measured. Post-mortem examination revealed progressive fibro-nodular changes in lungs. Biochemical parameters excepting EIC in both models showed significant (p< 0.001) gradual rise. Duration dependent biochemical changes in BALF due to silica were found responsible for progressive morbidity and may be considered as early markers for diagnosis, thereby, preventing increasing morbidity and death.