The Netrin-1mRNA Expression In The Cerebral Cortexes After Rats’ Transient Cerebral Ischemia

Objective To find out whether netrin-1plays a role in the neurological functionrecovery after cerebral ischemia by doing research on whether netrin-1mRNA in rat’scerebral cortex is affected bytransient cerebral ischemia.Methods35normal healthy male Sprague Dawley rats weighing230-270g wererandomly divided into3group: sham operation group(n=5), normal group(n=5),andoperation group(n=25). According to the difference in reperfusion time, the operationgroup was divided again into five subgroups:1d,4d,7d,14d and21d(n=5). In theoperation group, the rats’right middle cerebral arteries were occluded90minutes toestablish tMCAO model with the thread occlusion method. In the sham operationgroup, the rats received the same surgical operation as the rats in the operation group,except that the depth of thread intracranial was shorter than that in the operation group.Rats in the normal group did not receive any operation. Rats in the operation groupwere executed. We collected the cerebral cortexes in the ischemic core, the ischemicborder, the ipsilateral normal and the contralateral normal. The cortexes in the areacorresponding to the ischemic core were collected after rats in the sham operationgroup and the normal group were killed. Rats in the sham operation group were killedat1day after90min tMCAO. The expression of netrin-1mRNA in these cortexes wasdetected by real-time RT-PCR.Results Compared with the normal group, the expression of netrin-1mRNA inthe cortexes in the ischemic core and the ischemic border showed obvious increase at1day after the tMCAO (p<0.01). With reperfusion time lasting longer, the level ofnetrin-1mRNA expression increased gradually. At the14th day, the expressionreached their peak, and then decreased. And the expression of netrin-1mRNA in ischemic core was higher than that in ischemic border at each point of reperfusiontime (p<0.01). The expression of netrin-1mRNA in the cortexes in the rats from thesham operation group and the expression in the cortexes in the ipsilateral normal andthe contralateral normal in the rats from the operation group showed no changecompared with that in the normal group (p>0.05).Conclusion The reperfusion injury after transient cerebral ischemia can affect theexpression of netrin-1mRNA in the cerebral cortexes in the ischemic core and theischemic border, which suggests that netrin-1may participate in somepathophysiological processes after cerebral ischemia. Therefore, Netrin-1may helprecover neurological function after cerebral ischemia.