Experimental Study Of Biological Of Peripheral Nerve Induced By PLGA-Laminin Complex Nerve Conduit

Peripheral nerve injuries are very common in clinic. Epineurium suture is still widely used, which could not provide accurate direction for regeneration axons and lead to the formation of scar to effect functional recovery. Nerve guide duct is better than other methods, therefore we design the study, which includes cell toxicity and compatibility experiment in Vitro. Based on these, PLGA-LN compounded nerve guide duct is used to repair sciatic nerves compared with epineurium suture and common PLGA nerve guide duct to evaluate the results of different methods for repairing nerves.There were two groups,T1 group and T2 group,T1 group:T1L,epineurium suture;T1R, PLGA;T2 group: T2L, PLGA-LN; T2R, PLGA.When the concentration of the fluid with PLGA reached 10mg/ml,the growth rate of RSC96 was above 80%,which indicated PLGA had lower toxicity. RSC96 was cultivated on PLGA membrane and TCPs, RSC 96 was fusiform shaped in PLGA group, whose shape was similar to TCPs group,which indicated PLGA had better cell adhesion and compatibility. RSC 96 was fusiform shaped in PLGA group, whose shape was similar to TCPs group, which indicated PLGA have better cell adhesion and compatibility. RSC96 was cultivated on PLGA membrane and LN membrane, after 48 hours, S-100 immunofluorescence was applied, which indicated LN group was better than PLGA group. Exogenous laminin can promote adhesion and growth of SC.The number of proximal myelinated fibers was no obvious difference brfore 12 weeks, T2L group was better than other groups at 24 weeks.The thickness of sheath of T2L group wass better than other groups at 8 weeks for the proximal part. And the distal part was quite different from the proximal one. The number of myelinated fibers and thickness of sheath of T2L group was better than other groups at 8 weeks. The special staining disclosed that T2L group in which the regenerated axons aligned regularly and the sheath was mature was better than other groups. We can conclude that LN from PLGA-LN can promote proliferation of SC and accelerate regeneration and maturation of myelinated fibers. TSCI of T2L group in which muscle fibers were aligned regularly and closely was better than other three groupsat 12 weeks and 24weeks (P<0.05),muscle fibers were aligned regularly and not closely in T1R and T2R groups, muscle fibers were aligned irregularly and not closely in T1L group. We concluded that the atrophy degree of T2L group was lighter than other groups because it got earlier reinnervation .In normal situation, S-100 distributes conditionedly in peripheral nerves, there is dynamic balance among synthesis,excretion and transport, destruction of balance induces decrease of S-100 necessarily.We found that there was almost no expression at 1 week, increased a little at 2 weeks, the express of T2L group was better than other groups at 8 weeks(P<0.05),the expression of S-100 trended stable after this.We concluded that LN from PLGA-LN can promote proliferation of SC and accelerate regeneration and maturation of myelinated fibers.The express of T2L group was better than other groups at 2 weeks(P<0.05), we found that expression of Gap-43 increased obviously, then attenuated, the expression of Gap-43 trended stable after 10 weeks. The relative quantity of Real-time PCR of Gap-43 also identified the point. The number of apoptosis of motor neuron of cornu anterior medullae spinalis reached the highest at 2 weeks,T2L group was less than the other groups(P<0.05),then attenuated at 1 day and trended stable after 8 weeks.We concluded that LN from PLGA-LN can promote proliferation of SC and accelerate regeneration and maturation of myelinated fibers and protect motor neuron of cornu anterior medullae spinalis .The change of ultrastrucutre in 4 groups identified that T2L group was better than other groups at 8 weeks including both CV and Amp(P<0.05), We concluded that LN from PLGA-LN can promote proliferation of SC and accelerate regeneration and maturation of myelinated fibers to promote stimulation conduction.As above-mentioned, we concluded that PLGA with better compatibility and adhesion has lower toxicity for SC, exogenous LN can promote growth and adhesion of SC in Vitro. We also concluded that PLGA-LN compounded nerve guide duct can promote regeneration and maturation of axons ,decrease the apoptosis number of cornu anterior medullae spinalis and protect motor neuron of cornu anterior medullae spinalis , reinnervation of target organs.