A Research On Delaying The Muscular Dystrophy That The Implanting Of Streptomycin Composite Degradation Membrane Into The Local Muscle That Defects Of Spinal Cord

The damage and repair of the central nervous system has been the resolving problem in the neurosurgery areas.It was generally held that when the central nervous system injuries,it can not be completely renewable,and there comes the dysfunction in the past.But in fact,it is not the central nervous fiber that lacks the regeneration.In 1992,Reynolds and some other people first found that the adult brain cells striatum can be value-added differentiation glial cells and nerve cells.It broke the concept that the adult central nervous system can not regenerate.The central nervous system regeneration failed after injury mainly because of the local environmental effects at present.That is the secondary gliosis after the spinal cord injury.Scar formation is the mechanical obstacles for the hindered nerve fiber regeneration and extension.This experiment uses the sartorius muscle caudal spinal cord defect of the bridge,inserts the sustained-release compound containing streptomycin degradation of membrane into the local spinal cord injury,and observes the nerve regeneration and influence upon the functional recovery.We purchased night adult dogs from China Medical University Animal Center.They are clean,male and female informality,weight 20-25 kg,and are kept of a normal temperature,humidity 60%.We randomly divided the night dogs into six experimental groups and three contrary groups.The experimental group was released the streptomycin membrane degradation into the defect partial spinal cord.The contrary group was not.We developed the streptomycin release degradation membrane ourselves and it have been national patent(Patent No.200410021474.0).This degradation of membrane contains a drug side and a non-drug side,and it sustained-release in vivo degradation.The dogs were fixed in the operating table by intraperitoneal injection anesthesia of 2%sodium pentobarbital(25mg/kg).District of conventional was shaved for disinfect,exposed of L_3-4spinal segment,and was cut of 0.8 cm.We used the autologous sartorius muscle caudal spinal cord defect ends of the bridge. For the experimental group:six dogs in the spinal cord defect bridge site placement streptomycin composite membrane degradation(including drug side close spinal cord injury);for the contrary group:three dogs in the spinal cord defect of the non-bridge placement membrane degradation.After conventional treatment,we observed the morphological changes of the spinal cord bridge location and function recovery observed at different times.We did the general observation the state of animal after the surgery.The dogs had the pressure sores within two months.There occurred almost no pressure sores during the 8-25 months of surviving.Even if there were rupture of skin it can heal quickly.The dogs had urinary incontinence and they are even obvious gross hematuria,but the survival of more than 10 dogs,urinary incontinence will be the situation has markedly improved,and can gradually restore nearly normal animals in a relatively stable state of survival.We cut the bridge site after 8,18 and 25months respectively to observe the spinal cord.By Mallory and HE staining,ordinary optical microscope,the experimental group membrane of the spinal cord defect bridge less connective tissue proliferation, and the connective tissue membrane marked hyperplasia.The contrary group had a huge amount of collagen fibers hyperplasia in the spinal cord defect bridge, there was no significant migration between the two boundaries.We gave the bridging defect of the spinal cord osmium of acid staining and Oso₄ myelin,in the light microscope,the experimental group have more black or blue myelinated nerve fibers exist,the contary group did not see the myelinated nerve fibers,and there are occasionally visible black myelinated nerve fibers anomalies,a sausage-shaped,perhaps it is because of a large number hyperplasia in the connective tissue contracture.Experimental group bridging defect of the spinal cord appeared the silver nitrate staining,light microscope membrane degradation of the medial fibroblasts and vitamin C silver staining particles less than its lateral.Under the electron microscope,it showed that the spinal cord defect in the bridge of the cross-sectional specimens,we can see more clearly the myelinated nerve fibers,in particular animal survival after more than 20 months.The myelin structure is clear,deep-colored,thick,axonal mitochondria, microtubules and has a clear microfilaments structure,this structure tends to become more normal nerve fibers.The medial collagen fiber membrane is smaller,neat,less and has a small quantity of membrane lateral coarse collagen fibers,and they are disordered,significantly more than the medial membrane.We did the electrophysiological indicators hours after the surgery.We directly stimulate sartorius of the muscle gastrocnemius muscles at the hip,a dog's leg involuntary moved,the EMG showed action potentials there,with the time goes on,the extension of action potentials is almost near normal.21 months after the surgery,it exposure L_3-4spinal cord injury directly,we stimulated the local hub side of the lower extremity directly,the dogs moved.Postoperative recovery of motor function:6 months postoperatively,the dogs began to put end activities,with the survival time of the extension,facing strong tail activities is becoming increasingly obvious.According to improved Tarlov Motor Scotol Act Classification Standard(0:not hindlimb activities.One: hindlimb mild activities.Two:hindlimb obvious activities.Three:hind legs can stand it should not take.Four:walking,movement instability,five:hindlimb activities(Movement)normal).Detection of dual-motor function,no dog has the leg activities,it is the 0 level;survival of 8-25 months,the hip,knee and toe of the dogs can be seen clearly in the Department of flexion and extension activities,and some dogs can be walking,Grade 2-4 with motor function.Dogs survive after eight months,the calf muscles and hip muscles are found for muscular atrophy,but survived 10-25 months,the period muscular atrophy did not change significantly.People generally believe that after the injury of the central nervous system, there comes dysfunction,nerve regeneration was mainly caused by the failure of connective tissue and the the interference of the nerve damage on local gliosis formation of connective tissue scar.We think that it is not the lack of central nervous fiber regeneration ability and not composed of spinal cord nerve fibers in the glial cells obstruct axonal regeneration,but the local connective tissue proliferation that is faster than the proliferation of glial cells,and the nerve fibers involved in Regeneration of glial cells can be according to the direction,it is because the spinal cord injury to the distal-proximal end of a cable-proliferation, thus it affects the regeneration of spinal cord nerve fibers success.We used the sartorius muscle bridge spinal cord to defect local placement streptomycin composite membrane degradation release,the experimental group:spinal cord defect Bridge Department and the surrounding tissue adhesion is not obvious; degradation of connective tissue membrane medial hyperplasia is not obvious, and membrane lateral connective tissue hyperplasia is obvious,in the light of the observation bridge it can be seen more myelinated nerve fibers,and the myelin structure is clear,deep-colored,thick,axonal mitochondria,microtubules and the microfilaments has a clear structure nerve fiber structure tends to become more normal,stimulate the spinal cord injury center of the side of a dog leg contraction.With time alter the extension of both lower extremities became clear forceful activities can run.According to Tarlov Motor Scotol motion detection method for the 2-4 level,the contary group:spinal cord defect bridging the peripheral tissue,and the huge amount of bridge the collagen fibers hyperplasia,the bridge did not see any of the myelinated nerve fibers.In summary,the results of this experiment study show that muscle fiber degeneration Bridge alter remnants of the membrane provide good access to the nerve fiber regeneration glial cells along the spinal cord injury of the membrane proximal end to the the distal end of a cable-proliferation order is conducive to the growth of axons and extended forward and improve the spinal nerve regeneration effect.It is worldwide recognized that Vitamin C may participate in fibroblast collagen synthesis fiber.When lack of Vitamin C,collagen protein hydroxylation is hardly to complete,and the synthesis of collagen fibers inhibited fibroblast activity decrease significantly.The experimental released the composite membrane degradation bridge in the disposal of all spinal cord defect streptomycin,reduced the local vitamin C concentration,controlled the inhibition of fibroblast collagen fibers,connected tissue hyperplasia preclude interference,provided a good local micro-environment to the spinal nerve regeneration.It is good for conducive to the axon regeneration and glial cells along the bridge muscle after muscle fiber degeneration and the remnants of the membrane growth and proliferation,and in the spinal cord injury it was two vertical ends of the cords of order,so as to achieve the repair and re-built of the spinal cord.