ABSTRACT
The effect of 12 weeks of cyclosporin A (CyA) (7 mg/kg) on the survival of vascularized
osteochondral allografts between rat strains-Dark Agouti (DA donor) and Lewis (recipient)-was
examined up to 6 months after grafting. Grafts were assessed by India-ink infusion
to examine their microcirculation, and by quantitative histology. Isografts (Lewis
to Lewis) survived at least 25 weeks, but displayed progressive deterioration due
to their non-weight bearing position. Rejection controls (allografts with no immunosup-pression)
showed rejection within 2 weeks. Allografts in immunosuppressed hosts remained healthy
for the 12-week period of immunosuppression, but deteriorated progressively during
the ensuing 14 weeks, particularly in the muscle, marrow, and growth plates. Graft
repopulation by host cells was assessed by transferring grafts into fresh non-suppressed
allograft hosts, following 12 to 26 weeks in the first, immunosuppressed host. All
grafts were rejected rapidly following the second transfer, indicating that little
or no cellular repopulation of the graft had occurred while in the first host.
