Suppressive effects of Perilla frutescens on spontaneous IgA nephropathy in ddY mice

Perilla frutescens (perilla) is a common herb used in Japan for garnishing raw seafood to protect the alimentary tract from inflammatory diseases. The present study was performed to investigate whether or not perilla prevents the development of lesions of IgA nephropathy in ddY mice which spontaneously develop this disease. After orally administering perilla extract to ddY mice from 8 to 42 weeks of age, the changes in urine, serum, and kidneys were evaluated. Perilla extract significantly suppressed proteinuria and glomerular IgA deposition (p < 0.01 and p < 0.05, respectively). The decreased serum IgA concentration in perilla-treated mice showed a significant correlation with glomerular IgA deposition. Such findings suggest that perilla reduced glomerular IgA deposition via suppression of IgA production in the serum. On the other hand, the nitric oxide concentration in the serum of perilla-treated mice was significantly higher than that observed in the controls. The addition of the sera of perilla-treated mice to quiescent cultured murine mesangial cells resulted in a cell proliferation which was less than in controls, suggesting that perilla might either directly prevent mesangial cell proliferation or prevent proliferation by regulating circulating cytokines. Such results indicate that perilla should prevent IgA nephropathy, thus representing a promising herbal medicine for glomerulonephritis.