Experimental study on repairment effect of endothelial progenitor cells after focal cerebral ischemia in rats

Objective To explore the repairment effect of endothelial progenitor cells (EPCs) on local vascular endothelium after focal cerebral ischemia. Methods Sixty healthy adult Sprague-Dawley (SD) male rats were randomly divided into 3 groups: control group (n = 5), sham-operation group (n = 5) and ischemia- reperfusion group (ischemia group, n = 50) which included 1 h, 3 h, 6 h, 12 h, 24 h, 2 d, 3 d, 4 d, 7 d and 14 d after reperfusion subgroups (n = 5 in each group). The middle cerebral artery occlusion (MCAO) model was established. After occlusion, the rats were suffered from cerebral ischemia for 2 hours, and then reperfusion was given at different time as mentioned above before decapitation. The expressions of peripheral blood CD34 and cerebral AC133 were measured by flow cytometry and immunohistochemistry, respectively. Results The expression of CD34 in ischemia group was obviously lower than that in control group and sham-operation group at 3 d, 4 d and 7 d after reperfusion (P 0.01, for all), and returned to normal at 14 d after reperfusion, compared with control group and sham-operation group, difference was not seen (P 0.05, for all). At 4 d after reperfusion, positive expression of AC133 was found in part of vascular endothelial cells of the medium and small vessels in ischemic semi-dark band area at the infarcted cerebral hemisphere side in ischemia group. The expression of AC133 was all negative at other times in other groups. Conclusion At early cerebral is- chemia-reperfusion, the expression of peripheral blood CD34 highly decreased, and the expression of cerebral AC133 was positive in ischemic semi-dark band area at the infarcted cerebral hemisphere side. This suggests that endogenous EPCs may take part in cerebral vascular repairment after cerebral ischemia-reperfusion injury.