effect of dexamethasone on preventing tibial nerve conduction velocity loss in tourniquet neurepathic rat

introduction: ischaemic-reperfusion nerve injury has been suggested as the mechanism for post-tourniquet limb paralysis. as dexamethasone (dex) has been shown to prevent ischaemic-reperfusion process in some tissues, we tested the hypothesis that this drug would reduce tourniquet induced nerve injury. methods: 36 male wistar rats (200-250 gr) were chosen and divided randomly into 6 equal groups as sham operated, vehicle, control and treatments (dex1, dex2 and dex3). tourniquet was applied to the right hind limb of all animals except of sham and vehicle groups for 3 hours at the beginning of experiments. animals of control and vehicle groups were injected by 1 cc vehicle (normal saline containing 4% ethanol). animals of dex1, dex2 and dex3 groups were injected by 1mg/kg, 2mg/kg and 3mg/kg dexamethasone solution respectively 30 min before fastening tourniquet, 30 min after releasing tourniquet and daily during the week of experiment. motor nerve conduction velocity (mncv) was measured one week after releasing the tourniquet. results: mncv of tibial nerve in response to nerve stimulation were measured at 1 week post-tourniquet release. application of the tourniquet for 3 h decreased significantly (p<0.001) mncv in all animals. dexamethasone administration in doses of 2mg/kg and 3mg/kg (dex2 and dex3 groups) resulted in a significant improvement of mncv (p<0.001) in comparison to control group. conclusion: these data indicated that dexamethasone administration in doses of 2mg/kg and 3mg/kg could prevent nerve conduction velocity loss in tourniquet neurepathic rat.