Abstract

The authors studied the ultrastructural changes of rat kidney following intravenous administration of paraquat, utilizing intravenous injection of saline for control. Thirty eight Sprague-Dawley rats were divided into three groups (two as control group, eighteen as experimental group I and the rest eighteen as experimental group II). Control group was received 1㎖ of saline, experimental group I was received 20㎎/㎏ of paraquat and experimental group II was received 40㎎/㎏ through tail vein. Each of three animals was sacrificed 12, 24, 36, 48, 60 and 72 hours after administration to the group I and II, respectively. Each of two animals was sacrificed 72 hours after saline injection in the control group. Then both kidneys were extracted out and observed light and electron microscopically. The results were summarized as follow: Light microscopically, the renal tubular epithelial cells revealed slight congestion and edema without other significant pathologic changes. Electron microscopically, ultrastructural changes were usually confined to mitochondria. All proximal and distal convoluted tubular epithelial cells showed moderate mitochondrial swelling with decrease of cristae, vacuolation and increased electron density of matrix in 24 hours after in group I. In the group II, changes were similar but more severe. The results obtained in this experiment suggested that mitochondria were the main intracellular organ affected by paraquat, and that these mitochondrial changes were considered to be reversible.