Effect of Sho-saiko-to extract on HGF and TGF-beta levels of intraorgans in liver-injured rats after partial hepatectomy.

To examine the effects of Sho-saiko-to extract on liver regeneration, Sho-saiko-to extract (0.75%, 1.5% or 3%) was administered to 70% partial hepatectomized rats with dimethylnitrosamine-induced liver-injury. S phase cell number, liver retinoid levels, hepatocyte growth factor (HGF) and transforming growth factor-beta (TGF-beta) levels in each intraorgan were measured as indicators of liver regeneration. Three to seven days after hepatectomy, HGF and TGF-beta levels of the liver and spleen of the Sho-saiko-to extract groups were significantly different from the levels of the ordinary food group (P < 0.05-0.1). HGF levels in the Sho-saiko-to extract groups were approximately 1.3-1.8 times higher in the liver and approximately 1.8-2.1 times higher in the spleen compared with the levels found in the ordinary food group. TGF-beta levels in the Sho-saiko-to extract groups were approximately 0.38-0.47 times the level in the liver and 0.58-0.77 times the level in the spleen of the ordinary food group. There was no difference in HGF and TGF-beta levels of the kidney and lung between the Sho-saiko-to extract group and the ordinary food group. There was a significant and positive correlation between HGF level and S phase cell number in the liver (r = 0.826, P < 0.01). There was a significant and negative correlation between TGF-beta level and the retinoid level in the liver (r = -0.696, P < 0.01). In addition, the levels of the active constituents of Sho-saiko-to extract (glycyrrhetic acid, baicalin and baicalein) showed high values in the liver and spleen of partial hepatectomized rats, and increased from the third day after partial hepatectomy. These results show that Sho-saiko-to extract induces liver regeneration by increasing the production of HGF and suppressing the production of TGF-beta in the liver and spleen of partial hepatectomized rats. It was considered that the increase in the Sho-saiko-to extract active constituent levels in the liver and spleen greatly influences this action.