Experimental Substantiation of the Retraction Mechanism of Diastase Formation of the Nerve Transsection and Addition to Methods Its Treatment

Relevance Mechanisms of formation and treatment of the interval space between stumps of sectioned nerve remain one of actual and poorly studied factors of formation of hypercollagen scar of nerve and nevroma. The purpose of the study The goal of the work is study of possibility of retraction of nerve fibers in formation of interval between stumps of sectioned nerve and an attempt at its inhibition. Materials and methods Signs of retraction of nerve fibers on human amputated extremities are studied with aid of silver impregnation of fixed preparations by Bielschowsky-Gros. For experimental study of regularities of contraction of myelinated and myelinles nerve fibers at their section there are used models of living preparations of vertebrate and invertebrate animals. With aid of phase-contrast computerized videomicroscopy, a possibility of participation of contraction of nerve fibers in an increase of space between stumps of sectioned nerve is studied. A possibility of medicament inhibition of this retraction with aid of blockers of cytoplasmic mobility is shown. Electrophysiological methods are used for study of effect of these substances on neuromembranes and a possibility of use of the tested blockers is checked in experiments of treatment of the whole animals. Results and their discussion On fixed histological preparations of nerves of damaged and amputated human extremities there are detected signs of contractile activities of nerve fibers. In experiments on isolated living fibers for the first time demonstrated is dynamics of the bidirectional retraction of myelinated nerve fibers, which accepts their participation in enlargement of diastasis of cross-sectioned nerves. On myelinles axons with preserved neuronal bodies there is studied action of blockers of contractile activity of the cytoplasm: nimodipine, cytochalasin, blebbistatin, and colchicine. There is proved participation in retraction of axons of the main protein polymers of the axoplasmic cytoskeleton and a possibility of use of these blockers for inhibition of posttraumatic retraction of nerve fibers. Electrophysiological experiments have shown a low toxicity of these agents and a possibility of their use for treatment of the traumatic diastasis of nerves in experiments on the whole animals. Conclusion 1. There is shown the capability for retraction in myelin nerve fibers of human and other vertebrates after transaction of nerves. 2. Based on experiments on living single neurons with preserved processes, a hypothesis is formulated about participation of active contraction of axons in mechanism of formation of diastasis. 3. There is analyzed the ability of several main blockers of the axoplasm motility: cytochalasin B, blebbistatin, colchicine, and nimodipine to stop traumatic retraction of neurites. 4. The absence is shown of pathological influences of the studied inhibitors on electrophysiological properties of the neuromembrane, which admits their use for treatment of diastasis at transaction of nerves in the whole experimental animals. Key words Nerve diastase, nervous fibres retraction, mechanism axoplasm retraction, axon retraction inhibitors