Introduction: A growing body of evidence has shown cognitive and motor disorders in patients with hepatic encephalopathy. The aim of the present study was to examine changes in rearing behavior as an index for locomotion and balance during induction of hepatic encephalopathy in rats. We also examined plasma and/or serum analysis after 28 days of a common bile duct ligation in rats as a model of hepatic encephalopathy. Methods: Male Wistar rats weighing 300-350 g were used. For induction of hepatic encephalopathy a common bile duct was transected but sham control operation only consisted of laparotomy without bile duct resection. On day of surgical laparotomy (day 1) before the surgery and also every 7 days after the surgery until day 28, the two experimental groups of sham control and the bile duct ligated group were examined for rearing behavior. On day 28 of the surgery, blood samples were collected from the heart of the animals, and plasma and serum were separated from each blood sample in different tubes for biochemical analysis. Results: The results of a two-way repeated measure ANOVA showed that rearing behavior was significantly decreased from day 7 after the bile duct ligation in rats with ligation compared to the sham control group during 28 days of the experiments. Biochemical analysis of serum and plasma with independent t-test showed significant decreases in fasting blood sugar (P˂0.001), albumin (P˂0.01) and creatinine (P˂0.001) in rats with bile duct ligation compared to the sham control group. In addition, the results showed significant increases in serum levels of aspartate aminotransferase (P˂0.001), alanine aminotransferase (P˂0.001), and also plasma level of ammonia (P˂0.001) in rats with bile duct ligation compared to the sham control group. Conclusion: According to the results, it can be concluded that bile duct ligation induces chronic liver failure and hyperammonemia that in turn leads to hepatic encephalopathy. In addition, the decrease in re
