Experimental Study On Electrophysiological Mechanism And Functional Recovery Of Oculomotor Nerves

Experimental Study on Electrophysiological Mechanism and Functional Recovery of Oculomotor NervesOculomotor nerve injury is often occurred during the brain trauma and craniotomy, which can result in the paralysis of the extraocular muscles and the oculomotor handicap, and then greatly affect the life quality of patients. Hower, up until now the functional recovery of damaged oculomotor nerve is still a tough problem. Recently some scientists have been pursuing the goal of many efficient ways to repair posttraumatic oculomotor nerves. Yet not a general theory was approved on the regenerative mechanism of posttraumatic oculomotor nerves. The paper has been fund by Science & Technology department of Shanghai, 'Study of functional recovery on posttraumatic oculomotor nerves' (02QB 14045).The following have been included in our study: establishment of the Beagle canines model of oculomotor nerves injury; making up the stimulating electrode and recording electrode to be specialized in our experimental study; to explore the electrophysiological and histological characteristic of normal oculomotor nerves; to establish a mathmatical model and to simulate by Biocybemetics; to investigate the changes on electrophysiological aspect of posttraumatic oculomotor nerves and the effect of electric stimulus during recovery ofposttraumatic oculomotor nerves.PartⅠ: Establishment of the Animal Model of Oculomotor Nerves InjuryObjective To create more feasible and reproducible dog model of oculomotor nerves injury. Methods The posterior segments of oculomotor nerves in cavemous sinus were exposed in 10 Beagle canines after craniotomy, different neurophysiologic parameters were administrated, and the compound muscle action potentials(CMAPs)of obliquus inferior muscle were recorded successfully. After cutting of the oculomotor nerves, end-to-end anatomosis were used to anatomical reconstruction of the damaged oculomotor nerves immediately. Results All the procedures used in the study have been well tolerated by Beagle canines. Ocolomotor nerves were exposed completely, end-to-end anatomosis were done successfully. Conclusion The animal models have been established to study on the functional reconstruction and shown great reproducibility .The study will serve as the foundation for the development of a lager animal to research the reconstruction of the oculomotor nerves and other cranial nerves.PartⅡ: making up the stimulating electrode and recording electrode to be specialized in our experimental studyⅡObjective To make up the stimulating electrode and recording electrode which can be used to study on electrophysiological characteristic of oculomotor nerves. Methods Some primitive material were chosen to make up hand-made electrodes to meet the experimental study, such as Platinum, Lucite, Acupuncture needle. Results Property of the stimulating and recording electrodes was confirmed well by the depressor nerve and vagus nerve discharge in rabbits. Conclusion The electrodes have been maken up successfully to study on the electrophysiological characteristic of Beagle canines' oculomotor nerves, and the property of sensitivity and anti-interference has met the experimental need.PartⅢ: The electrophysiologicai and histological characteristic of normal oculomotor nerves in Beagle caninesObjective To investigate the electrophysiological and histological characteristic of normal oculomotor nerves in Beagle canines. Methods The posterior segments of oculomotor nerves in cavernous sinus were exposed in 8 Beagle canines after craniotomy, different neurophysiologic parameters were administrated, and the compound muscle action potentials(CMAPs)of obliquus inferior muscle were recorded by Med Lab System. Histological aspects of oculomotor nerves were observed with light microscope and electron microscope. Results Ocolomotor nerves were exposed completely, and bioelectrical signals were acquired successfully. The maximum amplitude of bioelectrical signals is about 510μv. Conclusion The key point to attain ideal signals is indeed earthing model. The oculomotor nerve was made of two kinds of fibers with different diameter and myelin sheath.PartⅣ: The establishment of mathmatical model and the Simulation by BiocyberneticsObjective To describe the electrophysiological law by Function in Mathematics or Equation, and to simulate by Biocybemetics. Methods The mathmatical model and Simulation were done by Simulink. Results The expression of Function in Mathematics is y=0.54427x~5-2.7671x~4＋4.6956x~3-2.8737x~3＋0.66571x-0.0019639. Conclusion The mathmatical model proved by Simulation has been established successfully.Part V: The changes on electrophysiological aspect of posttraumatic oculomotor nerves, and the effect of electric stimulus during recovery of posttraumatic oculomotor nervesObjective To explore electrophysiological changes of oculomotor nerves in different time points ,and to observe he effect of electric stimulus during recovery of posttraumatic oculomotor nerves. Methods The CMAPs of obliquus inferior muscle were recorded successfully in different time points. Two electric stimulus models were applied to observe the recovery of posttraumatic oculomotor nerves. Results There is a developmental changes on electrophysiological aspects of posttraumatic oculomotor nerves .The function of posttraumatic oculomotor nerves can recover partly, but the recovery of sphincter muscle of pupil was earlier than that of extraocular muscles. The CMAPs of obliquus inferior muscle were recovered significantly at the third month in electric stimulus group. Conclusion Developmental changes were showed on electrophysiological aspects of posttraumatic oculomotor nerves, and electric stimulus is benefit for the functional recovery ofposttraumatic oculomotor nerves.