Preliminary Experimental Study On Role And Mechanism Of Agmatine In Regeneration Of Facial Nerve Injury

Objective To observe the effecting and presume the mechanism of agmatine in regeneration of facial nerve injury.Methods 48 SD male rats were randomly and evenly divided into normal,control and Agm treatment groups.The bilateral facial nerve main trunks were transected.Coaptation of the proximal and distal stumps of the cut nerve was achieved by suturing the epineurium of nerve using a 10-0nylon thread under the operating microscope. The Agm treatment group was peritoneal injected with 100mg/kg agmatine once a day for a week. Saline-injected rats served as controls.The normal group was untreated.Then each group was randomly and evenly divided into two parts. At the 2 weeks,concentrations of Brain-derived Neurotrophic Factor in brain-stems were observed by Enzyme Linked Immunosorbent Assay;at the 4 weeks after operation,about 3~4mm distal regenerated nerve segment was dissected,cut into sections.The sections were processed for staining using Luxol fast blue,then observed the number of axis-cylinder and area of nerve tract on microscope equiped with a video camera connected to morphormetric digitizing software.Results Totally 48 rats entered the final analysis without any loss.At the 2 weeks,the BDNF concentrations of facial nucleus at brain-stem in Agm treatment group and control group rat were higher significant than that in the normal group,and the former was higher obviousely than later one, the differencas were significant axon ratio and the thickness of the myelin sheath were greater than the contorl group,statistical analysis was significant.At the 4 weeks after operation,myelin sheath and plenty of vacuolations were observed widely in the control group;meanwhile,few regenerated axis-cylinders were observed.A few infiltrative monocytes were observed in the Agm treatment group,and regenerated axis-cylinders passed the transected part,and a lots myelinization was formed.Number of axis-cylinder and area of nerve tract in the Agm treatment group and normal group were more than those in the control group,and those in the Agm treatment group were inferior to the normal group, statistical analysis was significant.Conclusions Agm accelerated facial nerve regeneration,and the mechanism may be connected to that it could increase the concentrations of BDNF in facial nuclues in SD-rats.