The Effect Of Viper Venom Nerve Growth Factor (vNGF) On Neuronal Plasticity In Rat After Cerebral Ischemia Reperfusion Injury

Objective: To investigate the significance and mechanism of Intracerebroventricular injection viper venom nerve growth factor (vNGF) in rat nerve regeneration after cerebral ischemia reperfusion injury.Methods: Taking the ninety clean grade healthy male Wistar rats,middle cerebral artery suture method was used to establish the focal cerebral ischemia-reperfusion (I/R) injury model. The rats were randomly assigned into vNGF-25u group(n=18), vNGF-50u group(n=18), vNGF-100u group(n=18), ischemia reperfusion(I/R) group(n=18) and sham operated(s) group. Each vNGF group were injected the corresponding dose of vNGF by means of improved lateral ventricle catheterization method. Evaluated neurofunctional status of rats on the basis of longa standardization everyday after surgery. The expression ofβ-tubulin mRNA and DCX mRNA in rat brain tissues which were collection at 2,7,14 days after surgery were evaluated by the Real time PCR. Results1. Neurological deficit score: the highest scores happened in two or three days after ischemia-reperfusion injured, then it decreased gradually. Injection of vNGF could improve neurological function to bring down neurological deficit score.2.DCX expression: DCX mRNA expression began to increase from the second day in each group. It was most expressed on the 7th day but the least on the 14 th day with the ischemia time lasting. In the same time, the expression of DCX in vNGF group was highest in three groups but shame group was least; The expression in vNGF-50U group was the most every time; (P <0.01).3.β-tubulin expression:β-tubulin mRNA expression in I/R control group was first decreased and then increased afte cerebral ischemia, keeping the most level in the 7th day. While the expression in vNGF group was gradually raised; In the same time, the expression ofβ-tubulin in vNGF group was highest in three groups and the shame group was least . Theβ-tubulin protein expression was aslo improved with the concentration of vNGF increased (P <0.01).Conclusion: Method of Intracerebroventricular injection vNGF after cerebral I/R injury was a positive intervention measures. It was not only promoting neural progenitor cell proliferation and migration, but aslo contributing nerve regeneration and restoration of nerve function. The possible mechanism maybe depend on two reasons:the positive regulation ofβ-Tubulin pathway or strengthened the migratory effect of Doublecortin.