[Expression and dynamics of peptidergic nerve fibers in granulation tissue after distance osteosynthesis]

The transmitters and/or modulators calcitonin gene-related peptide (CGRP), substance P (SP), neuropeptide Y (NPY) and vasointestinal polypeptide (VIP) are supposed to be involved in bone growth, fracture healing and internal remodeling. Immunohistochemical proof of neuropeptide positive fibers in normal bone let us assume that these substances effect the early phase of fracture healing. Exact time of appearance of neuropeptide positive fibers, localisation in the bone, chemospecifity and mode of genesis are unknown so fare. Research was done on a model of distance osteosynthesis of the rabbit tibia. Primary and secondary antibodies were used for indirect immunohistochemical technique. We put more strength on the concrete stereological calculation of length of the nerve fibers than on a conventional statistical evaluation. After histological preparation of tissue specimens from the interfragmental gap and the bone marrow beside the gap the neuropeptides CGRP, SP and NPY were immunohistochemically expressed. Sprouting of CGRP- and SP-positive nerve fibers has its origin in the bone marrow. A vascularisation in the early state of osteoneogenesis after fracture seems impossible without the nerval peptidergic influence and transmission.