Objective: To observe the activity of nuclear factor-kappa B(NF-kappa B) during reperfusion after temporary brain ischemia and to evaluate its effect.
Methods: The brain ischemia-reperfusion(I/R) model of mice was established with ligating bilateral common carotid arteries and bleeding for 0.3 ml in the tail. Abnormal nervous symptoms (ANS) were recorded. Immunohistochemical technique was used to detect the activity of NF-kappa B subunit P65 and the inhibitory factor-kappa B alpha(I-kappa B alpha) in cerebral cortex during different periods of ischemia and reperfusion. Their mRNA expressions were also measured by RT-PCR.
Results: NF-kappa B P65 activity significantly increased 30 minutes after the reperfusion, peaking at the 2nd hour, and remaining high within 24 hours (all P < 0.05). But the mRNA expression didn't change much; I-kappa B alpha and its mRNA expression began to decrease at 30 minutes after the reperfusion, peaking at the 2nd hour after the reperfusion (P < 0.05) and then gradually restored. Positive correlation was found between NF-kappa B P65 activity and ANS (P < 0.05), while negative correlation was shown among I-kappa B alpha, its mRNA, and ANS (P < 0.05, respectively).
Conclusion: Both activated NF-kappa B and decreased I-kappa B alpha exist in the neural tissues of mice at the early stage of brain ischemia-reperfusion. The activated NF-kappa B may be involved in the ischemia-reperfusion injury.