A Possible Role of Endoneurial Fibroblast-Like Cells in the Resolution of Endoneurial Oedema Following Nerve Crush Injury

Abstract

Endoneurial oedema is a salient feature of all types of neuropathy. Its elimination is crucial during the complications of nerve recovery. The objective was to study a possible role of the endoneurial fibroblasts in the resolution of nerve edema. Forty-two albino male rats aged between 30 and 40 days (weight 200 g to 250 g) were used in this study. The left sural nerves of 36 rats were subjected to crush injury at one to three-week intervals with six animals per interval. The right and left sural nerves of the remaining six rats were used as controls. At the end of the second week after crush injury, the endoneurium showed channel-like spaces that were lined by fibroblast-like cells and collagen bundles that contained degenerated myelin, and were connected to the subperineurial spaces. Flattened fibroblast-like cells were arranged in several layers in the subperineurial, forming barrier-like cellular sheets localizing to the endoneurial oedema in the space. Fibroblast-like cells also wrapped around the regenerating nerve fibres with their branching cytoplasmic processes. During the third week, the flattened fibroblast-like cells formed nearly continuous cellular sheets in the subperineurial spaces. Macrophages were frequently observed between these cellular barrier-like sheets and in the subperineurial. The endoneurial fibroblast-like cells form barrier-like cellular sheets that probably localise the endoneurial oedema in the subperineurial space. It also appear to create endoneurial channel-like spaces containing degenerated myelin and endoneurial oedema, which may be helpful in localizing and resolving such oedema.

Telocytes in the Normal and Pathological Peripheral Nervous System

“…Thus, TCs/CD34+SCs have been associated with neuroinflammation in the peripheral nerve [ 103 , 104 ] and with Charcot–Marie–Tooth disease [ 105 , 106 ]. They participate in myelin degradation [ 51 ] and in the resolution or location of endoneurial oedema in the sub-perineurial space following nerve crush injury [ 107 ]. Endoneurial progenitors expressing PDGFRa can participate in heterotopic ossification [ 108 ].…”

Telocytes inside of the peripheral nervous system – a 3D endoneurial network and putative role in cell communication

“…Many authors were tempted to reevaluate the fibroblasts and fibroblast-like cells. In fact, there are not yet established criteria to discriminate very well the differences between real phenotype of fibroblasts and many other fibroblast-like cell populations [2,80,88,89,94,95]. Moreover, Röyttä et al (1987) appreciated endoneurial fibroblasts as endoneurial fibroblast-like cells [96].…”

“…The spindle-shaped cells with rectangular or triangular bodies of cells with slender long cytoplasmic processes were described but no assimilation with endoneurial TCs is mentioned. In a recent published study concerning a putative role of endoneurial fibroblast-like cells in the reduction and finally resolution of endoneurial edema after nerve trauma, Elbarrany & Alasmari [94] evaluate that endoneurial fibroblast-like cells might represent around 2-9% of the endoneurial cells. They reported that endoneurial fibroblast-like cells gradually modified their morphology becoming flattened with long-branching cytoplasmic processes and finally form a barrier-like cellular layer, and consequently are involved in localization of endoneurial edema following nerve crush injury.…”