[Ultrastructure of a sciatic nerve allograft preserved at an ultralow temperature].

In the experiment, performed on dogs ultrastructure of the ischiatic nerve allograft, preserved in liquid nitrogen (-196 degrees) has been studied. In 7 days after the operation in the transplanted piece of the nerve trunk certain phenomena, similar to the Wallerian degeneration are noted, while viability of neurilemma cells is preserved. Processes of second degeneration are mainly completed by the end of the first month after the operation. During this time active regeneration of nervous fibers is noted; it is accompanied with neutralization of the graft. The latter is mostly expressed in 6 months after the operation. The dynamics studied on ultramicroscopic rearrangements of the cryopreserved graft proves the previously obtained data on possibility of its use in clinics for substitution of defects in peripheral nerves.