title: Effects of cessation of immunosuppression on skeleton reconstructed by vascularized bone allograft in rats.
abstract: In the present study, we investigated the effects of cessation of immunosuppression on skeleton reconstructed by vascularized allogenic bone transplantation in a rat tibio-fibula graft model. Twelve-week-old male 25 Dark Agouti rats with the major histocompatibility antigen (MHC) RT1a were used as donors and age-matched male 25 Lewis rats with MHC RT1l were used as recipients. Among them, 20 rats were randomly allocated to 8-week cyclosporine A (CsA) followed by 8-week CsA vehicle group or continuous 16-week CsA group. The remaining 5 rats received CsA for 8 weeks followed by no further treatment for next 40 weeks (long-term observation group). In the CsA followed by vehicle group as well as the continuous CsA group, the structure of the reconstructed bones was maintained, though the transplanted bones in former group were found to be partly non-vital. The CsA followed by vehicle group had higher bone mineral density of the transplanted bones and stronger strength of the reconstructed bones than the continuous CsA group. In the long-term observation group, the structure of the reconstructed bones was still maintained and the transplanted bones were almost vital. These results suggest that long-term strong immunosuppression may not be necessary for successful reconstruction of large bone defect by vascularized bone allograft.
authors.affiliation: Department of Orthopedic Surgery, Yamaguchi University School of Medicine, 1-1-1 Minamikogushi, Yamaguchi 755-8505, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Ikeda
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Shigetomi
authors.forename: Koichiro
authors.initials: K
authors.lastname: Ihara
authors.forename: Tetsu
authors.initials: T
authors.lastname: Tsubone
authors.forename: Takahiro
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Hiroo
authors.initials: H
authors.lastname: Kawano
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Sugiyama
authors.forename: Shinya
authors.initials: S
authors.lastname: Kawai
mesh_terms: D015502:Absorptiometry, Photon; D000818:Animals; D015519:Bone Density; D016025:Bone Transplantation / Q000276:immunology* / Q000473:pathology; D016572:Cyclosporine / Q000494:pharmacology*; D005360:Fibula / Q000378:metabolism / Q000473:pathology / Q000637:transplantation; D006085:Graft Survival / Q000187:drug effects*; D016867:Immunocompromised Host; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011917:Rats, Inbred Lew; D020127:Recovery of Function; D013977:Tibia / Q000378:metabolism / Q000473:pathology / Q000637:transplantation; D014184:Transplantation, Homologous
chemical_list: D007166:Immunosuppressive Agents; D016572:Cyclosporine