Effects of Puerain(葛根素) on the expression of nuclear factor-κB in rats after global cerebral ischemia/reperfusion

Objective: To study the protective effects of Puerain(葛根素) on rats after global cerebral ischemia/reperfusion. Methods: Wistar rats were randomly divided into three groups: group A (sham operation group, n=25), group B(ischemia/reperfusion group, n=25) and group C (Puerain treated group, n=25). The model of global cerebral ischemia/reperfusion was induced in group B and group C by means of Pulsinelli's method. The activation of nuclear factorB(NF-κB) and the expression of inhibitory protein-κB(IκB) in hippocampus CA1 region after ischemia for 10 minutes and reperfusion for 2, 6, 12, 24 and 48 hours were examined by immunohistochemical method. At the same time, the expression of tumor necrosis factor-α(TNF-α) mRNA were measured by in situ hybridization method, and HE staining was also performed to detect the number of surviving neurons. Results: The activation of NF-κB and the expression of TNF-α mRNA began to increase at 2 hours after reperfusion, respectively increased to the highest peak at 6 hours and 12 hours and gradually decreased, but it was still obviously higher than sham operation group at 48 hours after reperfusion(all P0.01). The expression of IκB began to decrease at 2 hours after reperfusion, dropped to the bottom at 6 hours, and gradually increased to the level at 2 hours(all P0.01). With the reperfusion prolonged, the number of surviving neurons became lower(P0.01). Puerain decreased the activation of NF-κB at every time point and the expression of TNF-α mRNA from 6 to 48 hours (all P0.05), increased the expression of IκB and the number of surviving neurons (P0.05 or P0.01). Conclusion: The experiment shows that Puerain could protect the brain from global cerebral ischemia/reperfusion injury, and the mechanism might be related to its increasing the expression of IκB and decreasing the activation of NF-κB and the expression of TNFα mRNA.