Experimental Study On Immunological Endurance Of Mice Nerve Transplantation Induced By Intrathymus Injection Of Allogene

Objectives:(1) to introduce immunetolerance in mice sciatic nerve allograft by intrathymic injection of allogene. (2) to compare the effect of fresh sciatic nerve allotransplantion and cold preserved sciatic nerve allotransplantation with different diameter.Methods: the first experiment Immunetolerance in mice sciatic nerve allograft by intrathymic injection of allogene: 48 (Balb/c) mice were divided into 4 groups randomly: Group A (intrathymus injection),Group B(nerve self graft), Group C (cold preserved nerve graft) and Group D(nerve allograft under immunosurppressant). In Group A the MHC antigen was extracted from spleen cell of C57BL/6 donor mice and injected into the thymus of Balb/c receptor mice. Then the sciatic nerve of the donor mice was transplanted into the receptor. The allograft sciatic nerve segments of groups were harvested and nerve electrophysiologic analysis, histological analysis and immunologic analysis were made at the 3rd week. The second experiment:(1) Compare the effect of fresh sciatic nerve allotransplantion with different diameter: to study the effect of fresh self sciatic nerve graft with different diameter. The 40 SD rats with the right sciatic nerve defect (10mm) were divided into four groups for the fresh self sciatic nerve graft with different diameters. Group A (sciatic nerve transplanted to sciatic nerve diameter 1:1),Group B (radial nerve to sciatic nerve diameter 0.8:1), Group C (median nerve to sciatic nerve diameter 0.6:1) and Group D (ulnar nerve to sciatic nerve diameter 0.5:1), The electrophysiologic analysis and histological analysis were made at the 4^th week and the 6^th week respectively. (2) Compare the effect of cold preserved sciatic nerve allotransplantation with different diameter: to explore the effect of cold preserved nerve allograft with different diameter. The 40 SD rats with the right sciatic nerve defect (10mm) were also divided into 4 groups for the cold preserved nerve allograft. Group E (sciatic nerve to sciatic nerve 1:1), Group F(radial nerve to sciatic nerve 0.8:1), Group G(median nerve to sciatic nerve 0.6:1) and GroupH ( ulnar nerve to sciatic nerve 0.5:1) The electrophysiologic analysis and histological analysis were made in the 4^th week and the 6^thweek respectively. Results: the first experiment Immunetolerance in mice sciatic nerve allograft by intrathymic injection of allogene: Nerve conduction velocity was not significantly difference. (Group A 38.23m/s to Group D 36.39m/s,P>0.05 ). The effect of the Group B of histology, electrophysiology and immunology was the best in the group A,B,C,D. the second experiment: (1) compare the effect of fresh sciatic nerve allotransplantion with different diameter: nerve self-graft there was no significant difference in the nerve conduction velocity of nerve self graft at Group E,F,G, H 4weeks and 6 weeks postoperative (p>0.05). the arrangement of the axons was neat and the myelin sheath was integrity in the proximal end of the self-graft segment 4 weeks after surgery. The new regenerative nerve fibers were found in the middle of the self-graft segment. Few infiltrated lymphocytes was been seen. The neural fascicle was in good order in the distal end of the self-graft segment but only few regenerative axons were found. 6 weeks after surgery the regenerative axons increased the calibers. The number of the axons increased in the distal end of the segment.. (2) Compare the effect of cold preserved sciatic nerve allotransplantation with different diameter: nerve allograft the effect of the nerve allograft in the group E,F,G,H was significant difference (P<0.05), among which the effect of the group E was best and the group H was the worst after. 4 weeks after surgery but the effect of the group H was best and the group E was the worst after 6 weeks after surgery. A few infiltrated lymphocytes was seen in the proximal end of the nerve allograft segment. Many hollow tubes were found in the middle of the segment. The new regenerative nerve fibers were fine. Few regenerative axons in the distal end of the segment. 6 weeks after surgery the diameter of the axons increased although far less than the calibers of the nerve self graft groups. Much more lymphocytes infiltrated. ConclusionThe first experiment Immunetolerance in mice sciatic nerve allograft by intrathymic injection of allogene : the specific immune tolerance can be induced in the sciatic nerve allograft by intrathymus injection of MHC allogene.The second experiment: the effect of the nerve self graft was correlated closely with the diameter of the donor nerve segment and receptor segment. If the diameter of the donor nerve was half larger than the one of receptor. The effect of which was similar to the effect of the same diameter one. In the sciatic nerve allograft group the effect of the large diameter allograft segment was better than the small one at 4 weeks after surgery. Oppositely the effect of the large diameter allograft segment was worse than the small one at 6 weeks after surgery.