Inflammatory Reactions In The Procession Of Peripheral Nerve Defect Repair

The repair of peripheral nerve defects is a long-term problem in neurosurgery and usually requires nerve graft repair.Due to high differentiation of nerve tissue,slow regeneration of peripheral nerve fibers,difficulty in regenerating nerve fibers,the repair effect of peripheral nerve injury is not ideal.In recent years,studies have found that the inflammatory response after peripheral nerve injury also has an important effect on the repair of peripheral nerve defects.The activity of inflammatory cells and the expression of inflammatory cytokines(inflammatory factor,IF)are the main manifestations of Inflammatory reaction(inflammation)In the repair of peripheral nerve defect,inflammatory reaction is an unavoidable process,and moderate inflammatory reaction is helpful for promoting the repair of peripheral nerve defect.To study the regularity of inflammatory reaction in the repair of peripheral nerve defect,it benefits for the repair of peripheral nerve defect.The development of tissue engineering has made cell transplantation technology treatment of nerve injury a hot topic in recent years.Fibroblasts secrete collagen and fibronectin and other matrix proteins,providing prophase support for nerve regeneration,while guiding the migration and accumulation of Schwann cells and the growth of nerve fibers.At present,fibroblasts are mainly applied to the repair of skin in tissue engineering.Alginate and shell powder are biologically degradable materials which are widely used in artificial nerve materials.They have good histocompatibility,biodegradability and certain biomechanical properties.It can be seen that presetting the shell matrix-calcium alginate in the nerve conduit facilitates the survival of the seed cells in the nerve conduit.To investigate the role of fibroblasts in the repair of sciatic nerve repair in rats with defective inflammatory responses and repair effects.In this paper,Sciatic nerve(SN),Autograft(Aut)and End-to-end nerve anastomosis(ENA)were used as the control group.three kinds of artificial nerves were prepared from cellulose and polylactic acid,namely nerve conduit(NC),Nerve conduit with shell matrix and calcium alginate hydrogel(HC),fibroblasts shell matrix-calcium alginate hydrogel and fibroblasts(FHC)were used to bridge the 10 mm sciatic nerve defect in rats by bridging the three artificial nerves.At the a series of time points,HE staining and immunofluorescence staining were used to investigate the activity of inflammatory cells in the repair of peripheral injury.Fluorescence quantitative PCR was used to detect the expression of inflammatory factors and nerve repair-related cytokines in the repair of peripheral nerve injury.Thus,we explore the changes of inflammatory response in the repair of peripheral nerve injury,in order to provide a basis for the follow-up study of the peripheral nerve repair.In the inflammatory response,the results of smear HE staining showed that the proportion of white blood cells in the three groups of artificial nerves gradually decreased on the 3rd day,7th days,14 th days,and 30 th days after the artificial nerve transplantation.The proportion of leukocytes in the fibroblast group(FHC)was lower than that in the nerve conduit(NC)and hydrogel group(HC),indicating that the inflammatory response was gradually weakened,and the fibroblast group(FHC)inflammatory response was weaker than the other two groups.The results of real-time PCR showed that the pro-inflammatory factors IL-1,IL-6 and TNF-? were relatively higher on the 7th day after operation;the anti-inflammatory factors IL-4 and IL-10 were relatively higher on the 14 th day after surgery.The expression level of the inflammatory factors was gradually decreased from the 21 st to the 30 th day,and the expression of inflammatory factors in the fibroblast group(FHC)was lower than that of the other two groups.For the three artificial nerve repair effects,results of HE staining showed that the cells of fibroblasts group(FHC)were more closely arranged in the proximal and the conduit wall,indicating that the cells were more active,and the repair activity was more obvious after peripheral nerve injury comparing with nerve conduit(NC)and hydrogel group(HC)on the 14 th day after artificial nerve transplantation.Transmission electron microscopy showed that the nerve repair occurred in different degrees on the 21 th day of artificial nerve transplantation.The myelin sheath was forming and gradually wrapped the new axon.Compared with the other two groups,the myelin layer of the fibroblast group(FHC)was more obvious and the repair effect was better.Immunofluorescence observation of frozen sections showed that the number of new axons and Schwann cells in the fibroblast group(FHC)was more than that in the hydrogel group(HC)on the 150 th day after the artificial nerve transplantation,and the nerve conduit(NC)was the lowest.It is indicated that on the 150 th day after surgery,the fibroblast group(FHC)had basically completed the repair of peripheral nerve injury,while the hydrogel group(HC)and nerve conduit(NC)had not been completed,but the hydrogel group was better than the nerve conduit.In summary,transplantation of fibroblasts can relatively improve the inflammatory microenvironment of the sciatic nerve in rats,which is beneficial to the repair of sciatic nerve defects.