Efficacy of berberine in preventing brain injury induced by hepatic ischemia-reperfusion in mice: the relationship with GSK-3 β activity

Objective To evaluate the efficacy of berberine in preventing brain injury induced by hepatic ischemia-reperfusion (I/R) and the relationship with glycogen synthase kinase 3 beta(Gsk-3)activity in mice. Methods Forty-eight healthy clean-grade male C57BL/6 mice, weighing 20-25 g, were randomized into 3 groups (n=16 each) using a random number table method: sham operation group (S group), hepatic I/R group (I/R group) and berberine group (B group). The model of 70% liver I/R injury was established by clamping the portal vein and hepatic artery supplying left and middle lobes of the liver in mice anesthetized with 2% pentobarbital sodium 40 mg/kg. In B group, berberine 50 mg/kg was administered through a gastric tube once a day for 7 consecutive days starting from 7 days before operation. The equal volume of normal saline was given instead in S group and I/R group. The mice were sacrificed at 6 h after reperfusion, brains were removed and hippocampal tissues were harvested for microscopic examination of pathological changes (with a light microscope) and for determination of cell apoptosis (by TUNEL), superoxide dismutase (SOD) activity (by xanthine oxidase method), malondialdehyde (MDA) content (by thiobarbituric acid colorimetric method), expression of phosphorylated GSK-3β (p-GSK-3β) and GSK-3β (by Western blot), and opening of mitochondrial permeability transition pore (mPTP). The apoptosis index and p-GSK-3β/GSK-3β ratio were calculated. Results Compared with S group, the apoptosis index and MDA content were significantly increased, SOD activity and p-GSK-3β/GSK-3β ratio were decreased, and mPTP opening was increased in I/R and B groups (P<0.05). Compared with group I/R, the apoptosis index and MDA content were significantly decreased, SOD activity and p-GSK-3β/GSK-3β ratio were increased, mPTP opening was decreased (P<0.05), and the pathological changes of hippocampal tissues were significantly attenuated in B group. Conclusion Berberine can prevent the brain injury induced by hepatic I/R, and the mechanism may be related to inhibiting GSK-3β activity and thus inhibiting mPTP opening in mice. Key words: Berberine; Hepatic; Reperfusion injury; Brain injuries; Glycogen synthase kinase 3