Objective: To investigate the protective effect of Tanreqing injection and its five intermediates on carbon tetrachloride (CCl4)-induced acute liver injury in rats and preliminarily discuss its pharmacodynamical basis against acute liver injury. Method: Subcutaneous injection was given for several times to establish CCl4-induced acute liver injury models. Then the male rats were randomly divided into normal group

CCl4 model group

Tanreqing injection group

Tanreqing injection treatment group

diammonium glycyrrhizinate injection group

Scutellariae Radix group

Selenarcti Fel group

Caprae Hircus Cornu group

Forsythiae Fructus group and Lonicerae Japonicae Flos group. The drugs were given to experimental rats for seven days by tail intravenous injection. Rats’ body weight

liver/body weight ratio

serum biochemical analyses and histological assays were measured. Quantitative real-time fluorescent PCR (Real-time PCR) was employed to detect the mRNA levels of Na+-dependent taurocholate co-transporting polypeptide (NTCP)

sulfotransferase 2A1 (SULT2A1)

glutathione-S transferase A2 (GSTA2) and cytochrome P450 3A11 (CYP3A11). Result: As compared with the normal group

the body weight was significantly decreased

liver/body weight ratio was significantly increased

serum levels of alanine aminotransferase (ALT)

aspartate aminotransferase (AST)

alkaline phosphatase (ALP)

total bilirubin (T-Bil)

direct bilirubin (D-Bil) and total bile acid (TBA) were also significantly increased

with significant necrosis and denaturation of hepatocytes

and the mRNA expression levels of NTCP

GSTA2 and CYP3A11 were significantly reduced in CCl4 model group (P<0.05

P<0.01). As compared with the model group

Tanreqing injection could significantly restore liver coefficient

reduce serum biochemical indexes

and alleviate pathological inflammation of liver tissues. Moreover

the improvement effect of the intermediates on serum liver function indexes was showed as Forsythiae Fructus>Lonicerae Japonicae Flos>Caprae Hircus Cornu>Selenarcti Fel. As compared with the model group

the mRNA expression levels of NTCP

GSTA2 and CYP3A11 were markedly up-regulated in Tanreqing injection group and Forsythiae Fructus group; the mRNA levels of SULT2A1 and GSTA2 were significantly up-regulated in Selenarcti Fel group; and the mRNA levels of SULT2A1

GSTA2 and CYP3A11 were up-regulated in Lonicerae Japonicae Flos group (P<0.05

P<0.01). Conclusion: Tanreqing injection exerts a potent protective effect against CCl4-induced hepatic injury

and the possible pharmacodynamical parts of this activity likely included Selenarcti Fel

Caprae Hircus Cornu

Forsythiae Fructus and Lonicerae Japonicae Flos. The possible mechanism of this activity may be related to up-regulating the mRNA expressions of NTCP

SULT2A1

GSTA2 and CYP3A11 in liver and accelerating the metabolism of bile acids in hepatocytes.