Effects of dexamethasone in rat neonatal model of axotomy-induced motoneuronal cell death

In this study the effect of dexamethasone on the motoneuronal cell death an d the nuclear and somatic morphology changes occurring after peripheral ner ve transection in the neonatal rats has been determined. The study was performed on 3 day old Wistar rats. Animals were divided into 3 groups - control, axotomised, and axotomised and dexamethasone-treated.. The nerve transection was performed bilaterally. A dose of 0.5 mg/kg/24h d examethasone, administered i.p., was used. On day 7 after the operation the animals were sacrificed and the motoneurons in segments L4 and L5 in the s pinal cord were counted and their morphology was analysed. 25.88% cell loss was found in the axotomised group (p < 0.001 vs, control) versus 43.33% ce ll loss in the dexamethasone-treated and axotomised animals (p < 0.01 vs. c ontrol). Dexamethasone significantly decreased the number of the surviving motoneurons (p < 0.05 vs. axotomised). The axotomised. group showed enlarge ment of the somatic area and the maximal and minimal diameters of the cell while the dexamethasone-treated and axotomised group showed soma shrinkage and decrease in the minimal cell diameter. Our results propose a possible hazard towards the application of dexamethas one in the treatment of new-borns with concomitant nerve injuries.