|Budget Amount *help
¥2,600,000 (Direct Cost : ¥2,600,000)
Fiscal Year 1998 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1997 : ¥1,100,000 (Direct Cost : ¥1,100,000)
Fiscal Year 1996 : ¥900,000 (Direct Cost : ¥900,000)
We first assessed the maximal period of cryopreservation using an easy and cheap slow freezing instrument for tracheal isografts in 95 rats. The permissible period of cryopreservation to adequately maintain tracheal isograft viability in this simple system was found to be 3 months. Cryopreservation for 3 months at -80ﾟC in this system is considered to be acceptable in the clinical setting of many institutions because of its low cost and simplicity. Second, the effect of cryopreservation on tracheal allografts was assessed reaction by cryopreservation was not proved. Immunosuppression
was required for cryopreserved allografts even if long-term cryopreservation is practiced for tracheal allografts. The same assessment as the second experiment was then performed (Mixed Lymphocyte Reaction), but failed because of poor induction of immunization by stimulators. We must investigate the effect of cryopreservation on tracheal immunogenicity using second graft rejection response. Third, the usefulness of a short-course of immunosuppression after tracheal allotransplantation was examined in 43 rats. We concluded that 1.5 mg/kg of FK506 which was administered for only three
consecutive days after surgery may be used to maintain the morphology of tracheal allografts in rats for 28 days after transplantation. In future, we must maintain the long-term viability of tracheal segments using the same model with an additional dosage of FK506.