Objective To explore the effects of Chaihuang Qingyi Huoxue decoction on oxidative stress in the liver in the rat model of severe acute pancreatitis（SAP）. Methods A total of 128 Sprague-Dawley rats were randomly divided into four groups: Blank group

Sham group

SAP group

and Chaihuang group. A rat model of SAP was established by retrograde injection of 5% sodium taurocholate solution into the pancreaticobiliary duct through the duodenal papilla. After awakening from anesthesia

the rats in each group were given corresponding Chaihuang Qingyi Huoxue decoction or normal saline every 6 hours. The arterial blood and hepatic tissue of the rats were collected at 6

12

24

and 48 h after operation. HE staining was performed to assess the pathological changes of hepatic tissue. Biochemical assays were conducted to measure the levels of serum amylase（AMY）

alanine aminotransferase（ALT）

and aspartate aminotransferase（AST）as well as the content of superoxide dismutase（SOD）

catalase（CAT）

glutathione peroxidase（GSH-Px）

and malondialdehyde（MDA）in hepatic tissue. RT-PCR was used to determine the mRNA expression of heme oxygenase-1（HO-1）

and Western blot was used to measure the protein expression of HO-1. Results Compared with the Sham group

the Chaihuang group and SAP group showed significant pathological changes

significantly increased levels of serum AMY

ALT

and AST（P < 0.05）

significantly decreased levels of SOD

CAT

and GSH-Px in the liver tissue（P < 0.05）

significantly increased MDA activity（P < 0.05）

and significantly increased expression levels of HO-1 protein and mRNA in hepatic tissue（P <0.05）. Compared with the SAP group

the Chaihuang group showed significantly reduced pathological injuries of the liver tissue

significantly decreased levels of serum AMY

ALT

and AST（P < 0.05）

significantly increased activity of SOD

CAT

and GSH-Px in the liver tissue（P < 0.05）

significantly reduced MDA activity（P < 0.05）

and significantly increased expression levels of HO-1 protein and mRNA（P < 0.05）. Conclusion Chaihuang Qingyi Huoxue decoction has a protective effect against liver injury in a SAP model in rats

and the mechanism may be related to up-regulation of HO-1 expression and inhibition of oxidative stress.