The Impact Of Ilexonin A On Expression Of Vegf,vegfr2 And Neurogenesis After Cerebral Ischemia-Reperfusion In Rats

OBJECTIVE To explore the effect of IlexoninA on expression of VEGF, VEGFR2 and neurogenesis and its possible mechanism after cerebral ischemia- reperfusion in Rats.METHODS The model of Middle cerebral artery occlusion(MCAO) was established to transient focal ischemia by placement of an intraluminal filament at the origin of left middle cerebral artery. The rats were divided randomly into: control, sham operation, model and IlexoninA (IA71,142,285μmol·kg- 1) treatment groups. Neuronogical behavior was evaluated by Longa's scoring method. TTC staining was applied to observe cerebral ischemia in MCAO model group and IlexoninA treatment groups. Immunohistochemistry were used to observe the expression of VEGF, VEGFR2 positive cells in the ischemic brain tissue in theat different time of ischemia and reperfusion. Immunofluorescence were used to observe the expression of Nestin (neurogenesis Marker)positive cells in the SVZ in theat different time of ischemia and reperfusion.Western bloting were used to observe the expression of VEGF, VEGFR2 protein in the ischemic brain tissue and Nestin protein(neurogenesis Marker) in the subventricular zone in theat different time of ischemia and reperfusion.The effects of IA intervention (71,142,285μmol·kg- 1) on neurological deficit score and the expression of VEGF, VEGFR2 protein in ischemia surrounding areas and Nestin protein in ischemia SVZ were mainly quantified.And the effects of IA intervention (71,142,285μmol·kg- 1) on the positive cells of VEGF, VEGFR2 in ischemia surrounding areas and Nestin in ischemia SVZ were mainly quantified.RESULTS Neurological deficits of model were more at 3d(P<0.05 compared to 14d and 28d).In control and sham groups, there were scattered VEGF, VEGFR2 positive cells (mainly in the cortex), and the number of VEGF, VEGFR2 positive cells were peaked at 7d in model group. With the prolongation of reperfusion, the expression of VEGF, VEGFR2 decreased.VEGF, VEGFR2 protein in the control group and sham group was much less than model group.In model group, there was a certain amount at 3d after reperfusion, reached to peak at 7d, then reduced gradually, to 28d was still expression. Similarly, Nestin protein reached its peak at 7d after reperfusion, and then decrcased gradually, compared to other model times (P<0.05). After the intervention of IA71,142,285μmol·kg- 1, the neurological deficit score decreased significantly, and the expression of VEGF, VEGFR2 protein in ischemia surrounding areas and Nestin in ischemia SVZ were increased comparing to model group at corresponding time points (P<0.05), and the positive cells of VEGF, VEGFR2 in ischemia surrounding areas and Nestin in ischemia SVZ were increased comparing to model group at corresponding time points (P<0.05), with pronounced effct at dose of IA285μmol·kg- 1.CONCLUSION1.Cerebral ischemia reperfusion injury induced the expression of VEGF, VEGFR2 in the early time(at least 14d). It is possible that the early expression of VEGF, VEGFR2 were involved to promote the survival and remodeling of peripheral neurons ,with promoting the recovery of neurological function.2. IlexoninA can promote the the expression of VEGF, VEGFR2 in the early time(at least 14d).It may be passed through upregulation of VEGF, VEGFR2 to promote the repair and regeneration of neurons to play its role of neuroprotective.