| Peripheral nerve defect is one of the most common in clinical trauma. Due to all kinds of frequent accidents made the peripheral nerve defects remained relatively high morbidity. Clinically, nerve autograft was the primary means of treatment for neurological defects. With the development of tissue engineering material in recent years,biodegradable nerve conduit provides a new idea in the clinic. At the same time, the research of biological macromolecules which can promote the nerve cell proliferation provides a theoretical basis for the repair of nerve defect, such as a variety of stem cells,growth factors, Chinese herbal medicine and so on.The purpose of this study is to explore the effect of salidroside/collagen/PCL nerve conduit for repairing nerve defect, and to seek an optimal concentration of salidroside for repairing nerve defect. Firstly, preparation of salidroside /PLGA microspheres by W/O/W method. Then, nerve conduit shell was fabricated by electrospinning technology.Fabrication of nerve conduit core of containing different concentrations of salidroside(10μg/m L, 20 μg/m L, 40 μg/m L) was using the method of freeze drying. Nerve conduit core embedded in nerve conduit shell, and use 1% genipin cross-linked, to construct nerve conduit of containing different concentrations of salidroside. To evaluate the property of nerve conduit materials use scanning electron microscope.60 Wistar rats were randomly divided into 6 groups, the experimental group with 12 rats in each group, divided into 4 groups; the control group with six rats in each group,divided into 2 groups. With the method of removal of 15 mm sciatic nerve of rats to duplicate the nerve defect model. The experimental groups respectively bridging nerve defect with the corresponding nerve conduit. In the autograft group, suture the nerve with autograft nerve. In the defect group, remove sciatic nerve directly. Sciatic nerve function index was measured at 1, 3 and 6 months after surgery. Electrophysiological examination was performed at 3, 6 months after surgery. Nerve conduit materials and gastrocnemius muscle were removed and embedded in paraffin at 1, 3 and 6 months after surgery, and conventional HE staining. Nerve conduit materials was use Masson staining at 3 and 6months. Nerve conduit materials Immunohistochemical staining of myelin basic protein(MBP) and myelin basic protein 0(P0), and Immunofluorescence staining of S100 and NF, at 3 and 6 months. To evaluate the effect of nerve conduit containing salidroside for repair sciatic nerve defect by above methodThe results showed that salidroside /PLGA microspheres appear burst release phenomenon in 3 days. And the salidroside/PLGA microspheres release keep stable after13 day. The above results showed that the microspheres have a good sustained-release effect. The drug release duration is longer and can reach the requirements of drug release.The results of scanning electron microscope showed that the internal channels of the nerve conduit suitable for cell adhesion and growth.General observation after surgery showed that the rat appeared different degree of foot ulcers in 1 week and most serious in 1 month, at 3, 6 months began to recover.Furthermore, ulcer area in the group of collagen was more serious than that in the group of 20, 40 μg/m L, and the autograft group was not ulcers. The connection of regeneration nerve is good in each group in 6 months after surgery. Sciatic nerve function index showed that the motor function of each group gradually recovered in 1, 3 and 6 months after surgery. The effect nerve recovery in the group of salidroside 20 μg/m L was significantly better than that of the other groups(P<0.05), but the effect was less than that of the autologous nerve graft group. The recovery of latency(d Lat) / conduction velocity(CV) ratio was most significant in the group of salidroside 20 μg/m L and autologous nerve graft(P<0.05), and not significant compared with the normal side of the nerve conduction(P>0.05). The recovery effect was poor in other groups. The recovery of latency(d Lat) / conduction velocity(CV) ratio was significant in the group of salidroside40 μg/m L and not contain salidroside compared with the normal side of the nerve conduction(P<0.05). HE and Masson staining showed that the nerve conduit in the group of salidroside 10 μg/m L and 20 μg/m L had good degradation performance. And the regenerated nerve cells had a good growth status. HE staining of gastrocnemius muscle showed that muscle cell in the group of salidroside 20 μg/m L was atrophy from muscle morphology observation in 3 months. Muscle cell atrophy phenomenon alleviate in 6months after surgery. The recovery effect was not much difference compared with the group of autologous nerve transplantation. Myelin basic protein(MBP)immunohistochemical staining showed that the expression level of MBP in 6 months is higher than that in 3 months in each group. The expression level of MBP in the group of salidroside 20 μg/m L was higher than that in other groups and was lower than that in autologous nerve graft group. The result of Myelin protein 0(P0) immunohistochemistry staining was the same as MBP expression in each group. The above results indicated that the regenerated nerve had the myelin sheath structure, which could effectively conduct the nerve impulse, and was beneficial to the recovery of motor function.Immunofluorescence staining of S100 showed that the expression at 6 months was higher than 3 months, and the expression of the group of salidroside 20 μg/m L was higher than that of other groups. Immunofluorescence staining of NF showed that the regenerating nerve fibers grow along the direction of the nerve conduits.To summarize, nerve conduit of containing different concentrations of salidroside were fabricated in this research. Nerve conduit can reach the requirements of the control of drug release and have channels for cell adhesion and growth. The results of animal experiments show that the nerve conduit of containing different concentrations of salidroside can promote the regeneration of the defect nerve, and it also has a certain effect on the reconstruction of the motor function. The effect of nerve regeneration and recovery of motor function is optimum When the nerve conduit containing Salidroside at20 μg/m L. The effect between nerve conduit and autogenous nerve graft for repair sciatic nerve defect is not obvious. This nerve conduit has clinical research and application value. |
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