Immune rejection of a facial nerve xenograft does not prevent regeneration and the return of function: an experimental study.
Nerve grafts may be used to repair damaged peripheral nerves and also to facilitate spinal cord regeneration after experimental trauma. Little is known, however, about the possible use of xenografts and the role of immune rejection in the outcome of repair. In rats, excision of a short (7-8 mm) segment of facial nerve at its exit point from the skull base results in a permanent deficit in eye closure in the blink reflex. This deficit can be repaired by transplantation of a segment of either syngeneic rat facial nerve or xenogeneic Balb-C mouse sciatic nerve either with or without cyclosporine immunosuppression. With longer (15-20 mm) transplants, however, restoration of eye closure becomes dependent on cyclosporine administration. Thus, in a situation where nerve repair does not occur without a graft, a host immune attack has an attritional effect which is not sufficient to prevent repair over short distances, but becomes obvious when the regenerating fibres have to cross longer segments of transplanted tissue.
Choi
D
D
The Division of Neurobiology, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK. dchoi@nimr.mrc.ac.uk
Raisman
G
G
D000818:Animals; D016572:Cyclosporine / Q000494:pharmacology; D004333:Drug Administration Routes / Q000662:veterinary; D005123:Eye / Q000503:physiopathology; D005154:Facial Nerve / Q000187:drug effects / Q000276:immunology / Q000637:transplantation* / Q000648:ultrastructure; D020220:Facial Nerve Injuries / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D007165:Immunosuppression Therapy; D007166:Immunosuppressive Agents / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D008854:Microscopy, Electron / Q000379:methods; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology; D009416:Nerve Regeneration / Q000187:drug effects / Q000276:immunology*; D009504:Neutrophils / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D020127:Recovery of Function / Q000187:drug effects / Q000276:immunology*; D012583:Schwann Cells / Q000378:metabolism; D012584:Sciatic Nerve / Q000187:drug effects / Q000637:transplantation / Q000648:ultrastructure; D013194:Staining and Labeling; D016378:Tissue Transplantation / Q000379:methods; D014183:Transplantation, Heterologous / Q000276:immunology*
D007166:Immunosuppressive Agents; D016572:Cyclosporine