Effect Of Deep Cryopreservation On Limb Allograft Rejection In Adult Rats

Objectives:To establish approprite animal models for observing the effevts of deep cryopreservation on limb allograft rejection.Methods:There are 48 rats,include 16Wistar rats and 32 SD rats,divided them into 4 groups. Each group has 4 wistar rats and 8 SD rats,which Wistar rats were used as donators and SD rats as recipients, namely groups A:8,After amputation the donor limbs were irrigated with UW organ preservation solution at 25℃ and transplanted them into SD rats who had their own limbs cut off and observation; groups B:8,on the base of group A administrated immunosuppressive agent postoperatively for 4 weeks; groups C:8, After amputation the donor limbs were irrigated with UW organ preservation solution at 4℃ and were given deep cryopreservation on the donor limbs for 24 hours before transplanted them into SD rats who had their own limbs cut off and observation; groups D:8,on the base of group C administrated immunosuppressive agent postoperatively for 4 weeks. The 16 donor rars were given died after had cut off their limbs.After the operation , all the recipients were given benzathine berzylpenicillin, and their vital signs, together with changes of the allografts, observed. Radiograph was taken for each graft at 2,4,8,12 weeks.Immunological analysis was performed using spontaneous lymphoblast transformation rate(SLTR) and IL-2 assay.Results:A total of 32 rats received transplantation that was successful in 29rats. The graft A survival averaged (8.0±2.2)d and group C survival averaged (14.0±4.2)d, group B survival averaged (52.0±4.61)d and group D survival averaged (57.0±5.33)d which surviving for a long time more than group A and group C. The ratio of SLTR between group A and untransplantation group,,ratio of SLTR between group C and untransplantation group is below 2 respectively. The changes of IL-2 in group A were maximal and the difference between group A and group C reached significant difference statistically(P<0.01). Showing significant difference in the lengths of survival between group B,C,D with group A.(P<0.05).Conclusion:Cyropreservation combined with cyclosporine A has synergistic effect on reducing rejection response of revascularized limb allograft.The graft survival time in rats can be significantly prolonged by pretransplant deep cryopreservation of the allograft, which also help control acute rejection of the allograft.but it still can not take place of immunosuppressive medication.