A study on the pathogenesis of acute paraquat intoxication induced pulmonary injury

Objective To investigate the enzymatic levels of MDA and SOD in lung tissue and the intracellular concentration of Ca~ to explore the pathogenesis of acute paraquat(PQ)intoxication induced lung injury.Methods 36 SD rats were divided into PQ intoxication group and control group.Animals in intoxication group were given PQ at the dose of 20 mg/kg.The ultrastructural changes of lung tissue were observed while the MDA and SOD concentrations in the lung homogenate and intracellular Ca~ concentrations were measured. Results Pathological study revealed diffuse capillary endothelium and alveolar epithelium damage which resulted in alveolar edema,bleeding,hyaline membrane formation and alveolitis with intensive inflammatory cell infiltration.The level of MDA in the lung homogenate increased significantly and the level of SOD decreased significantly in intoxication group compared with control group (P0.01).The intracellular concentration of Ca~ was increased significantly compared with control (fluorescence intensity:82.91±28.68 vs 55.42±29.61,P0.01) which was most obvious on the second to the fourth day.Conclusion The pathogenesis of PQ intoxication is related to oxygen free radical overload and intracellular Ca~ homeostasis disequilibrium.