Therapeutic Potential of Two Derivative Prescriptions of Rokumijiogan, Hachimijiogan and Bakumijiogan against Renal Damage in Nephrectomized Rats

Background: Hachimijiogan (HJG) and Bakumijiogan (BJG), two derivative prescriptions of Rokumijiogan (RJG), were selected to investigate their renoprotective potential in the 5/6 nephrectomized (5/6Nx) rat model. Methods: Rats were treated with HJG and BJG orally at 150 mg/kg body weight/day once daily for 10 weeks after resection of 5/6 of the renal volume, and their renoprotective effects were compared with 5/6Nx vehicle-treated and sham-operated control rats. Results: Improvements in renal lesions, glomerulosclerosis, tubulointerstitial injury, and arteriosclerotic lesions estimated by histologic scoring indices in the HJG-treated group were compared with those in the BJG-treated group. HJG- and BJG-treated groups ameliorated the renal function parameters. Elevated levels of renal oxidative stress-related biomarkers were reduced, while decreased antioxidant defence systems (superoxide dismutase and the glutathione/oxidized glutathione ratio) were increased in the HJG-treated group rather than the BJG-treated group. In contrast, BJG administration significantly reduced expression of the inflammatory response through oxidative stress. The HJG-treated group showed a decrease in inflammatory mediators through the JNK pathway. To gain a deeper understanding of their therapeutic action, the effects of the main components detected in HJG and BJG were evaluated using the LLC-PK(1) renal tubular epithelial cell line, which is the renal tissue most vulnerable to oxidative stress. Corni Fructus and Moutan Cortex-originated compositions afforded important protection against oxidative stress induced by peroxynitrite. Conclusions: From our described and discussed analyses, it can be concluded that RJG-containing prescriptions, HJG and BJG are an excellent medicine for chronic kidney disease. In the future, appropriately designed clinical studies in people with chronic kidney disease are necessary to evaluate the renoprotective activities of HJG and BJG.