effect of intraneural injection of 5% phenol, glycerol and 5% phenol in glycerol in the albino rat sciatic nerve: a comparative histological and immunocytochemical study

ABSTRACT

The aim of the present study was to perform a comparative histological study on the effects of neuroblocking agents, namely 5% phenol, glycerol and combined 5% phenol in glycerol, injected intraneurally in the rat sciatic nerve. Twenty adult male albino rats were divided into 4 groups, 5 animals each. The right sciatic nerve of each animal was exposed and an intraneural injection of 0.1 ml of normal saline for the first group, 5% phenol for the second, glycerol for the third and 5% phenol in glycerol for the fourth group. Animals were sacrificed after 2 weeks and a part of the sciatic nerve distal to the site of injection was excised. Paraffin sections were prepared and processed for hematoxylin and eosin and for immunocytochemical staining to demonstrate S-100 protein. The results showed that the effect of intraneural injection of 5% phenol was directed primarily towards endoneurial blood vessels that appeared dilated and congested. Intraneural oedemna together with mononuclear cellular infiltration resulted in degeneration and destruction of nerve fibers. In case of intraneural injection of glycerol, axonal damage was more severe due to a direct toxic effect resulting in a massive destruction of nerve fibers. Intraneural injection of 5% phenol in glycerol caused intraneural oedema with minimal axonal damage. The present study showed that intraneural injection of combined 5% phenol in glycerol caused less endoneurial damage than injection of each agent separately