Protective effect of tetramethylpyrazine on expression of occludin after cerebral ischemia and reperfusion in rats

Objective To study the effects of tetramethylpyrazine（ TMP） on expression of occludin after brain ischemia-reperfusion（ I / R） in rats. Methods The focal cerebral ischemia-reperfusion model of middle cerebral artery occlusion（ MCAO） was established with intraluminal suture. The change of the permeability of blood-brain barrier（ BBB）was detected using Evans blue assay. The expression of occludin was detected wih immunohischemistry assay,real-time reverse transcription PCR（ RT-PCR） and western blot. Results The expression of occludin decreased significantly at the end of 3 hour and 72 hour of I / R group. The expression of occludin in TMP group was found significantly increased compared with that of the I / R group at the same time. Conclusion The down-regulation of occludin may be involved in the increase of BBB permeability induced by cerebral I / R injury; the up-regulation of occludin and recovery of function of tight junction and integrity of BBB may be one of the pathways of TMP in inhibition of cerebral edema after reperfusion.