Inhibitory effects of the herbal medicine Saiboku‐to on the proliferation of cultured murine mesangial cells

SUMMARY: Patients with certain types of glomerulonephritis often present with upper respiratory tract infection (URTI). In this in vitro study, we have examined several Japanese herbal medicines, Shosaiko‐to (TJ‐9), Saiboku‐to (TJ‐96), Sairei‐to (TJ‐114) and Ryokankyomi‐singenin‐to (TJ‐119), which are occasionally used for collagen diseases, chronic inflammatory diseases or renal diseases. In these drugs, TJ‐96 is used to treat bronchial asthma or URTI, which has anti‐inflammatory effects. In this study, we demonstrate that TJ‐9, TJ‐96 or TJ‐114 inhibits the proliferation of murine mesangial cells induced by platelet derived growth factor (PDGF) or tumour necrosis factor (TNF)‐α. Quiescent mesangial cells were stimulated with 10 ng/mL of PDGF or 100 U/mL of TNF‐α together with various concentrations of the medicines for 20 h. After incubation with 50μ/mL of TJ‐9, TJ‐96 or TJ‐114, 3H‐thymidine incorporation induced by PDGF was reduced to 26, 19 and 29% of the control; and 66, 56 and 75% on TNF‐α stimulation, respectively. TJ‐96 had a more intense inhibitory effect than TJ‐9 or TJ‐114. TJ‐119 had no significant inhibitory effect at the same dose. Northern blot analysis for PDGF‐B transcript after addition of TJ‐96 revealed a 24% reduction in PDGF‐B mRNA levels stimulated by recombinant PDGF‐BB, suggesting inhibitory mechanisms of autocrine production of PDGF. No cytotoxic effect against mesangial cells in culture was observed up to a concentration of 100 μg/mL of TJ‐9, TJ‐96 or TJ‐114 by lactic dehydrogenase release assay. By another cell viability assay, after medium with 50 μg/mL of TJ‐96 was replaced with only PDGF‐BB‐containing medium, 3 H‐thymidine incorporation was found to exceed the control, suggesting rebound proliferation. the present findings suggest that administration of TJ‐96 is beneficial for patients with mesangioproliferative glomerulonephritis accompanied by URTI, serving to regulate the effect on mesangial cell proliferation.