An Experimental Study On The Treatment Of Brachial Plexus Avulsion Injuries By Intraspinal Reimplantation With Neural Stem Cells And Schwann Cells

Roots avulsion injury is the most severe injury type of the brachial plexus lesions characterized by the interruption of rootlets from cervical cord, which always leads to flaccid arm completely or partly. It is very difficult to heal roots avulsion injury which is considered a world trouble. To regain the function of limbs, current surgical ways are based on nerve transposition and functional reestablishment. But the curative effect is not satisfied. Then, in order to reestablish neural passageway, some scientist began to repair nerve in spinal cord. They reimplanted avulsed nerve rootlets into the proper position and they observed that affected limb was also improved. However, the injury is interruption of the axon near to neurons,not only to result the interruption of nerve continuity, but also to damage the motoneurons . It is the main reason of bad curative effect to reimplant avulsed nerve rootlets merely.NSCs(neural stem cells),Which exist in the neural tissues extensively, have the capacity of self-renew and multi-directional differentiation. The neural tissues contained NSCs is gotten easily. The NSCs can be isolated and be cultured in vitro. Under some proper condition, NSCs can be induced to differentiate into neuron-like cells.This is the base which cell reimplantation heal the illness of the neural system.SCs(Schwann cells)is the glial cells of the peripheral nerveous system(PNS)which can support and protect nerve cells. SCs can also secrete many kinds of neurotrophic factors(NTFs)and form eligible microenvironment which is very important to the growth and the differentiation of the NSCs.In this study, we made the model of nerve rootlets avulsion injury. After a week,we reimplanted avulsed nerve roots into the spinal cord . At the same time, we also transplanted cell suspension of NSCs and SCs into the corresponding spinal cord segment. Then, we observe the fate of the NSCs such as survival, migration, differentiation and we also estimate the protective effect on motoneuron in the anterior horn of the spinal cord. It will provide theoretical foundation for the further study.1. The establishment and evaluation of the brachial plexus avulsion model in the Wistar rats.The rat model of C5～C7 nerve roots avulsion was made by posterior subscapular approach. After the operation , the function of affected limb were measured by the Terzis grooming test.Conclusions: 1 By the posterior subscapular approach, brachial plexus avulsion model can be made successfully, which is approximate with human brachial plexus roots avulsion injury.2 The nerve fibers of rat musculocutaneous nerve are mainly from C5～C7 nerve roots and no fibers from C8 take part in the formation of musculocutaneous nerve. 3 In this way, we can make experimental model conveniently without electrophysiology and get a high achievement ratio.2. Isolation, expansion, identification and induction of rat NSCsNeural stem cells were cultured by serum-free culture techniques within DMEM/F12 medium . Anti-Nestin Immunocytochemical staining were utilized to identified the Neural stem cells specially. Anti-MAP2, Anti-GFAP Immunocytochemical staining were utilized to identified the new born neurons and astrocytes respectively. In addition, the effect of the growth and differentiation were observed that Schwann cells promoted Neural stem cells. Conclusions: 1 We successfully isolated Neural stem cells derived embryonic rat spinal cord and cultured by serum-free culture techniques within DMEM/F12 medium . 2 The isolated Neural stem cells proved to own ability of self-renewal and multi-directional differentiation. 3 In vitro, Neural stem cells and Schwann cells can keep the state of mutualism.4 In the condition of co-culture,Schwann cells can promote the the growth and differentiation of neural stem cells.3 .Isolation, cultivation and identification of rat SCsSchwann cells were isolated by enzyme digestion and derived sciatic nerve of neonate rat. Then they were cultivated within DMEM medium including Forsklin and Bovine pituitary extract. Anti-S100 Immunocytochemical staining were utilized to identified the Schwann cells specially.Conclusions: 1 By enzyme digestion, we could get Schwann cells whose purity was 92%～94%; 2 We harvest first lot Schwann cells about ten days by enzyme digestion; 3 In vitro co-culture, Schwann cells can promote the the growth and differentiation of Neural stem cells. 4 An experimental study on the treatment of brachial plexus avulsion injuries by intraspinal reimplantation with neural stem cells and Schwann cellsThe model rats were divided into 4 groups at random, A group (simple nerve roots avulsion), B group(simple nerve roots reimplantation), C group(nerve roots reimplantation+neural stem cells transplantation), D group(nerve roots reimplantation+neural stem cells transplantation+Schwann cells transplantation). In the B group,C group,D group ,the avulsed roots were reimplanted one week after injury. The function of involved affected limb,Latency and CAMP of related musculocutaneous nerve, pathological changes and motoneurons score and migration ,survival and differentiation of cells transplantation were checked at 1week,4 weeks, 12weeks,24weeks of postoperation.Conclusions: 1 The model rats are suitable for this study, the method of combining nerve roots reimplantation with cell transplantation will establish the foundation to heal brachial plexus roots avulsed injury. 2 The method of combining nerve roots reimplantation with cell transplantation can improve the protective effect on motoneuron in the anterior horn of the spinal cord. 3 The transplanted neural stem cells can survive, migrate and differentiate into neuron in the spinal cord. 4 Within a living body of the rat , Schwann cells can afford support,protection, nutrition for the neural stem cells continuously, in addition, it can also promote the differentiation of the neural stem cells into neurone.