A. Ekelund et al., NEUROPEPTIDES IN HETEROTOPIC BONE INDUCED BY BONE-MATRIX IN IMMUNOSUPPRESSED RATS, Clinical orthopaedics and related research, (345), 1997, pp. 229-238
The effects of cyclosporin A on the occurrence of neuroendocrine pepti
des in bone induced by demineralized allogeneic and xenogeneic bone ma
trix were studied in rats, Cyclosporin A enhanced bone induction in de
mineralized allogeneic bone matrix implants by 40% to 50% at 4 weeks,
whereas there was no difference to the control group at 8 weeks, In de
mineralized xenogeneic bone matrix implants there was virtually no car
tilage or bone formation at 4 weeks, but some bone and cartilage forma
tion was seen at 8 weeks, In both cyclosporin A treated groups the net
bone formation in demineralized xenogeneic bone matrix implants was i
ncreased four to five times at 4 weeks, Cyclosporin A treatment did no
t alter the temporal occurrence or distribution of neuropeptide contai
ning nerve fibers in the bone induced by allogeneic bone matrix, Fiber
s containing substance P, calcitonin gene related peptide, neuropeptid
e Y, vasoactive intestinal peptide, and tyrosine hydroxylase were dete
cted in the ossicles of cyclosporin A treated and control rats, In the
xenogeneic bone matrix of the control group, no immunoreactive nerve
fibers could be detected at 4 weeks, but at 8 weeks all five neuropept
ides were detected, However, after cyclosporin A treatment immunoreact
ive nerve fibers could be seen at 4 weeks in the demineralized xenogen
eic bone matrix implants, Thus, immunologic properties of the inductiv
e matrix affect the yield of mineralized bone and the degree of innerv
ation, Cyclosporin A decreases the immune response and enhances the fo
rmation of bone and the number of transmitter identified nerves in dem
ineralized xenogeneic bone matrix induced ossicles.