Acute toxicity of Zhongshengmycin wettable powder in rat

  Objective  To understand the acute toxicity of of 3% Zhongshengmycin wettable powder in rat.

  Methods  To observe oral and dermal toxicity, 10 rats (5 female and 5 male) were given this product(dissolved in water) gavage at 5 000 mg/kg body weight or skin application at 2 000 mg/kg body weight, respectively. To study inhalation toxicity, the water suspension of this product was atomized by the aerosol generating device and 10 rats in each group were exposed to aerosols for 2 hours at dose 1 126, 2 031, 2 501, 3 539 and 4 464 mg/m³. The toxicity symptoms and signs were observed till day 14. The histological examination of lung in inhalation toxicity test was done.

  Results  No obvious poisoning symptoms of rats were observed after rats were treated by oral or dermal exposure to product. The rats had respiratory symptoms after they exposed to aerosol. The gross anatomy showed that there were hyperemia, hemorrhage and volume increase in the lung. Pathological examination showed disorganization of lung tissue and alveolar septum, thickening and break of alveolar wall. There was a large number of neutrophil infiltration and erythrocyte extravasation in pulmonary interstitium, and proliferation of vascular endothelial cell. The lung histopathology semi-quantitative score showed that the higher the dose, the more obvious the lung injury.

  Conclusion  Zhongshengmycin wettable powder could causes lung injury by inhalation.