| There are two kinds of skeletal muscle stem cells in human body: one is Satellite cells(SC),also called Myogenic progenitor cell(MPC); the other is Muscle derived stem cell(MDSC) or Sidepopulations(SP). MDSC is far less than SC in number. for muscle satellite cells plays the major role in muscle developing and regenerating, the received muscle stem cells in human body are mainly muscle stem cells. As the seed cells of muscle tissue engineering technique, there are lots of studies about bionomics culturing and identifying muscle stem cell in vitro . Some studies reveal that :muscle satellite cells are a cytogeny derived muscle, they are located in undifferentiated muscle derived cell colonia in skeletal muscle. Muscle satellite cells are lied between the skeletal cell membrane and the BM and have the features of self-renewal, versatility and plasticity. Although the mechanisms about muscle satellite cells transveral differentiation, span-series differentiation and retrodifferentiation are not clear, we have made some progress in muscle satellite cells transplantation.Some patients had already been better by transplanting muscle satellite cells for curing myodystrophy. For myodystrophy, transplanting muscle satellite cells is not only for supplying regeneration healthy cell muscle fiber, but also for bring normal gene message to host by the fusing of transplanting cells and host cells .Muscle satellite cells can be used for recovery of skeletal muscle and also can be used for recovery of low regeneration capacity myocardium. Empirical study indicated that in the field of improving infracted left ventricular, skeletal satellite cells of new-born animals function as the same as myocardium .Some reports that by transplanting cultured muscle satellite cells into injuried skeletal muscle,muscle function can be improved. Other reports reveal that muscle satellite cells can maintain skeletal muscle's humid weight, muscle fiber cross section area and the contents of actin. Some studies indicated that: muscle satellite cells have features like strong reproductive activity and adaptability, and their end cells are muscle cells with no oncogenicity ; also they have low immunogenicity in variant ,so it can survive for long time. So muscle satellite cells is one kind of good genetic carrier cell, they are easily modified and they are used as cytokines for expressing.The clinical application perspct of muscle satellite cells have already been expected though some studies needed to validate and explorate more.Recovery from peripheral nerve trauma is one of the most difficult questions, micro-surgery nerve structure recently used can't antagonize neurone, proximal end congeneric nerve-tract as well as nerve fiber correctly, possibly they can grow to each other by mistake and so we can't get ideal results, this phenomenon appear dominantly in long distance defect, and become the major factors that restrict peripheral nerve regeneration and functional recovery. How to accelerant nerve regeneration, screening ideal transplant for promoting nerve regeneration, and make the target muscle to obtain the innervation as soon as possible, is one of the most important processes to solve the problem of peripheral nerve regeneration after long distance injury. Some report point that: bridging peripheral nerve defect by bone pipe, artery, vein, fascia tube, collagen tube, polylactic tube and human amniotic base membrane as well as degenerated skeletal muscle made up from decalfificated bone have got experimental effects in some degree, but in clinical they don't work . In my experiment, we plan to transplant muscle satellite cells in nerve regeneration cabinet formed by degradated compound membrane, and observe the effects of its function on nerve regeneration, in order to provide a new study way for recovering large segment peripheral nerve injury in clinical.In my experiment we separate muscle satellite cells by two step enzyme digestion, purify by discontinuous density gradient centrifugation, then culture them in vitro. Serial subcultivation 14-20d, cells amplified to 1×10~7/ml and then to transplant. Before transplanting them we have to observe cell proliferation under the microscope and carry out immunohistochemistry detect. Experimental data indicated that the purity and numbers of muscle stem cells suspension have reached to literature standard and satisfied to experimental requirement.This experiment uses the biology degraded membrane which the Shenyang Medical college develops to repair the big mouse sciatic nerve 10mm damage, its principle is made the materials that have good biological compatibility and adaptation nerve and can be possible to degrade gradually in vivo into nimble modelling biological thin film that have certain permeability, can be able to carry on the material interchange,can make the blood vessel to grow well. This experiment indicate that the biologically degraded membrane in the repair peripheral nerve damage process, not only promote neuranagenesis chemotaxy display, but also can prevent the periphery fiber to grow into them, avoids the formation of the neuroma, and have on stomal scar,so it provides the directional channel and the relatively constant regeneration micro environment for injuried nerves. At the same time, the biologically degraded membrane that have been putted in vivo have the advantages of good organization compatibility, flexibility, may degrade gradually in vivo and absorb, does not need the surgery to take out, this experiment uses the biologically degraded membrane regeneration cabinet animal model to observe the regeneration of the peripheral nerve, so we may remove other influencing factors and provide the essential condition to neuranagenesis influence by all kinds of factors for the further study of regeneration indoor.This experiment's 16 grown-up Wistar big mouses are divided into the experimental group and the control group, we cut off the mice's right hind legs sciatic nerve, establish the nerve damage animal model. In experimental group, we inject the cultured homogeneity foreign myo-satellite cell suspension into coloboma nerve ends in regenerate cabinet which is wrapped by biologically degraded membrane; in control group: we inject equal saline into the same part as the experimental group. After the operation for 4 weeks, 8 weeks and 12 weeks, we detect big mice's walking, and compute sciatic nerve function index according to Bain formula. 12 weeks after the operation, we cut off regenerated nerve. Make light slice and the transmission electron microscope specimen by perosmic acid staining, then observe them under the microscope, with the opposite side sciatic nerve at the same part as control group. Uses motic image the advance3.2 micro image analysis system to analysis the far lateral section of regenerated nerve of two groups to observe the marrow nerve fiber number , marrow nerve fiber diameter and myelinic membrane thickness. We carry on two group of sample mean value T-test analysis by the SPSS 11.5 statistics softwares to. obtained data. There is obvious difference for P<0.05. The result of this experiment indicate that: the comparision between experiment group and control group: SFI, musculus gastroenemius wet weight survival rate, regenerated marrow nerve fiber number, the marrow nerve fiber diameter and myelinic membrane thickness and so on examinations all have the obvious difference and have statistics significance.At present, the myo-satellite cells' function and the survival condition in neuranagenesis cabinet are still not very clear, needs further deep research. This experiment suppose that, possibly the local microenvironment changed due to putting myo-satellite cells into nerve regeneration cabinet and promote the regeneration of nerve fiber; also possibly some myo-source products produced during the process of myo-satellite cells metabolism or cells death disaggregation can induce nerve fiber regeneration and function with promoting nerve growth substance together to promote nerve fiber regeneration. This experiment result indicate: putting myo-satellite cells in nerve regeneration cabinet may promote nerve fiber regeneration better and also can enhance the maturation of regeneration structure and recovery of functions. Thus, there is certain promotion function on recovery of peripheral nerve injury if we put foreign myo-satellite cells in nerve regeneration cabinet. In addition, we didn't found striped muscle-fiber in all of the regeneration nerve fibers, which reveal that myo-satellite cells didn't differentiated to muscle fiber in nerve regeneration cabinet and had no blockage effect for directional passway of nerve-regeneration. |
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