Peptidergic nerve fibres in granulation tissue during fracture healing after osteotomy

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 no rmal bone let us assume that these substances effect the early phase of fra cture healing. Exact time of appearence of neuropeptide positive fibers, lo calisation in the bone, chemospecifity and mode of genesis are unknown so f are. Research was done on a model of distance osteosynthesis of the rabbit tibia . Primary and secondary antibodies were used for indirect immunohistochemic al technique. We put more strength on the concrete stereological calculatio n of length of the nerve fibers than on a conventional statistical evaluati on. 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 fract ure seems impossible without the nerval peptidergic influence and transmiss ion.