Einfluß lokal applizierter Kortikoide auf die Morphologie peripherer Nerven nach Neurotmesis und mikrochirurgischer Naht*

Abstract

The present work deals with the morphology of cut peripheral nerves anastomosed by primary microsurgical suture. The important question was whether the well-known anti-inflammatory, anti-exudative and fibroblast-inhibiting effects of locally applied glucocorticoids can influence the morphology of degenerating and regenerating peripheral nerves. After cutting the saphenous nerve of the rabbit and prior to its microsurgical suture the synthetic crystalline glucocorticoids methylprednisolone, prednisolone and dexamethasone were applied between the distal and proximal nerve stumps (interfascicular surface application). After a defined time of two days up to a maximum of five weeks the suture site and adjacent parts of the nerve were removed and investigated by light microscopy and electron microscopy. The morphological findings of the degenerating and regenerating nerve structures with and without local application of the different corticoids were compared. The results show that after local application of glucocorticoids the formation of scar tissue and neuromata is decreased, thus supporting the processes of regeneration. This is a result of a reduction of fibroblasts in the new formation of the epineurium and in the endoneurium and a certain protective effect on the perineural cells. Furthermore, the application of the glucocorticoids seems to accelerate the breaking down of myelin and degenerating axons and the new formation of myelin sheaths by "activating" Schwann cells. These facts lead to an enhancement of nerve regeneration after microsurgical suture.

Cortisol promotes survival and regeneration of axotomised retinal ganglion cells and enhances effects of aurintricarboxylic acid

“…Higher numbers of regenerating axons than with vehicle injection were also found if cortisol was applied alone. This is in contrast to the findings of Becker et al [6] and several other studies, in which no enhancement of regeneration of damaged axons after the application of corticoids could be found [9,26]. On the other hand, better regeneration of cut nerves was also found [29].…”

“…However, this procedure may lead to wrong conclusions. Becker et al cut and re-sutured the nervus saphenus of rabbits and compared the neuroanatomical changes with and without local application of glucocorticoids [6]. They found that Wallerian degeneration, i.e.…”

Investigation of Three Drugs With Neuroregenerative Effects on Inferior Alveolar Nerve Injury in Rats

“…The most commonly used drugs in peripheral nerve injuries are steroids. Steroids demonstrate an antiin ammatory action by inhibiting the phospholipase A2, suppressing the macrophage inhibition factor, stabilizing the lysosomal and other membranes, granulocytes (Graham et al 1973 Becker et al reported that local steroid applications reduce the number of broblasts and scar tissue formations in peripheral nerve injuries (Becker et al 1987). In addition, in the same study, they reported that steroids prevented the neuroma formation with these effects and stimulated myelin sheath production through the activation of Schwann cells.…”