The dosage-efficacy/toxicity relationship of the 50% alcohol extracts of Polygonum multiflorum was comparatively investigated on either normal or CCl4-induced chronic liver injury rats, by determining the general condition, serum biochemical indices and liver histopathology, coupled with the factor analysis. The dosages were 10 and 20 g raw materials per kg body weight. Compared with the normal control group, the normal high dose group showed significant increases of the serum alanine transaminase (ALT), total bilirubin (TBIL), high mobility group box 1 (HMGB-1) and interleukin-1β (IL-1β) (P < 0.05 or P < 0.01), as well the frequent incidences of inflammatory cell infiltration, hepatic sinus enlargement and fiber stripes formation in histopathological sections. Compared with the model control group, the model low dose group showed significant declines of serum ALT, aspartate transaminase (AST) and total bile acid (TBA) (P < 0.05), as well the alleviation of vacuoles of hepatocytes, but no amelioration of the inflammatory cell infiltration and fibrous tissue hyperplasia; moreover, the model high dose group showed significant degeneration declines of serum HMGB-1, tumor necrosis factor-α (TNF-α) and IL-1β (P < 0.05, P < 0.01), as well the evident alleviation of vacuoles degeneration of hepatocytes, inflammatory cells infiltration and fibrosis degree. The factor analysis showed that the low dosage treatment had almost neither injuring effect on the normal rats nor protective effect on the model rats; while the high dosage treatment showed observable injuring effect on the normal rats, expressed by the significant increases of the factor-1 (HMGB-1, TNF-α and IL-1β as the main contributors) and factor-2 (TBIL, ALT and TBA as the main contributors) relative to the normal control group. The liver protective effect of the high dosage treatment could be observed with the significant reduction of the factor-1, indicating the effective alleviation of the expression of inflammatory cytokines. In conclusion, it could illustrated the phenomenon of symptom-based prescription theory of Polygonum multiflorum on rat livers: the high dosage of the herb had either an injuring effect on normal rats, or a therapeutic effect on the rats with chronic liver injury.

The liver injury induced by Polygonum multiflorum Thunb. (PM) was investigated based on idiosyncratic hepatotoxicity model co-treated with lipopolysaccharide (LPS) at a non-hepatotoxic dose. Sprague-Dawley (SD) rats were intragastrically administered with three doses (18.9, 37.8, 75.6 g crude drug per kg body weight) of 50% alcohol extracts of PM alone or co-treated with non-toxic dose of LPS (2.8 mg·kg(-1)) via tail vein injection. The plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were assayed and the isolated livers were evaluated for histopathological changes. The dose-toxicity relationships of single treatment of PM or co-treatment of LPS were investigated comparatively to elucidate the idiosyncratic hepatotoxicity of PM. The results showed that no significant alterations of plasma ALT and AST activities were observed in the groups of solo-administration of LPS (2.8 mg·kg(-1), i.v.) or different dosage (18.9, 37.8 and 75.6 g·kg(-1), i.g.) of PM, compared to normal control group (P > 0.05); while significant elevations were observed in the co-administration groups of PM and LPS. Treatment with LPS alone caused slight infiltration of inflammatory cells in portal area but no evident hepatocytes injury. Co-treatment with LPS and PM (75.6 g·kg(-1), i.g.) caused hepatocyte focal necrosis, loss of central vein intima and a large number of inflammatory cell infiltration in portal areas. When further reduce the dosage of PM, significant increases of plasma ALT and AST activities (P < 0.05) were still observed in co-administration groups of LPS and PM (1.08 or 2.16 g·kg(-1)), but not in LPS or PM solo-administration groups. Nevertheless, the co-treatment of low dosage of PM (0.54 g·kg(-1)) with LPS did not induce any alteration of plasma ALT and AST. In conclusion, intragastric administration with 75.6 g·kg(-1) of PM did not induce liver injury in normal rats model; while the 2 folds of clinical equivalent dose of PM (1.08 g·kg(-1)) could result in liver injury in the LPS-based idiosyncratic hepatotoxicity model, which could be used to evaluate the idiosyncratic hepatotoxicity of PM.