Soluble Protein In Degeneration Nerve Axon Growth

Object: To observe the effect of soluble proteins produced by sciatic nerve undergoing Wallerian degeneration on axonal growth Methods: co-culture system of dorsal root ganglia (DRG) and sciatic nerve segment undergoing Wallerian degeneration in vivo for 14 days was employed in this essay to observe the morphologic changes , and discontinue SDS-PAGE was used to separate the soluble proteins produced in Wallerian degeneration Result: (l)DRG was cultured in DMEM/F12 serum free medium for 6 days, the numerous ,crook and tender axons could not adhere each other; and DRG cultured in this medium is a good model for testing the effects of exogenous factors on axonal growth because the number of Schwann cells and fibroblast are rare. (2) DRG co-cultured with sciatic nerve undergoing Wallerian degeneration for 14 days in vivo in serum free DMEM/F12,1) sciatic nerve segment was added into co-culture system at the first moment, the axons were strong and straight and could adhered to each other, and the number of axons dramatically reduced compared with that of DRG cultured alone in serum free medium. 2) DRG cultured in serum free DMEM/F12 for 4 days, then the sciatic nerve segment was added into the culture system for 3 days, the axons became straight and part of them adhered to each other. (3)DRG was cultured in 10%FBS+DMEM for 3 days; axons were straight and could adhere to each other, and there are enormous Schwann cells and fibroblast. (4)DRG was co-culture with sciatic nerve segment in 10%FBS+DMEM; the axons were longer and surround the sciatic nerve segment which was regard as a new evidence for chemotropism. (5) 12 protein bands were got using SDS-PAGE, EL-1, neurotrophins and axonal growths inhibit factors might participate in those changes above. Conclusion: several aspect of axonal growth could be affected by soluble proteins coming from Wallerian degeneration. Significance:(1) The phenomenon that soluble proteins coming from sciatic nerve segment under going Wallerian degeneration make axonal number of the dorsal root ganglia decrease and axons adhere to each other are first observed in our essay. (2) the results indicate that ,(1) not all the soluble proteins could promote axons regeneration, so removing the inhibitory proteins and adding promoting proteins in regular sequence could facilitate repairing of damaged peripheral nerve. Here, "in regular sequence" is important, because the process of nerve regeneration can be separate into several different stages which different proteins take part in. Neglecting this characteristic would hamper axons sprout;(2)DRG cultured under serum-free condition is a good model to observe the biological effects of soluble proteins to axonal growth and this model found a basis for advanced study.