Long-term treatment with Hachimi-jio-gan attenuates kidney damage in spontaneously diabetic WBN/Kob rats

Diabetes mellitus is now the most common cause of end-stage renal failure. In this study, the effects of Hachimi-jio-gan on diabetic kidney damage in spontaneously diabetic WBN/Kob rats were examined. Oral administration of Hachimi-jio-gan to WBN/Kob rats for 25 weeks significantly suppressed urinary protein excretion. It did not affect-body weight loss or blood glucose levels, whereas it reversed the increase in kidney weight of WBN/Kob rats. Hachimi-jio-gan also reduced fibronectin and transforming growth factor β₁ (TGF-β₁) protein expression in the renal cortex. Furthermore, renal lipid peroxidation levels of WBN/Kob rats given Hachimi-jio-gan were significantly lower than those of untreated controls. Renal superoxide dismutase activity was elevated by Hachimi-jio-gan treatment in a dose-dependent manner. These results suggested that Hachimi-jio-gan could prevent diabetic kidney damage by reducing renal oxidative injury and expression of fibronectin and TGF-β₁ proteins, which are all involved in the pathophysiology of diabetic nephropathy.