Dexamethasone prevents vascular damage in early-stage non-freezing cold injury of the sciatic nerve

Non-freezing cold injury is a prevalent cause of peripheral nerve damage, but its pathogenic mechanism is poorly understood, and treat-ment remains inadequate. Glucocorticoids have anti-inlfammatory and lipid peroxidation-inhibiting properties. We therefore examined whether dexamethasone, a synthetic glucocorticoid compound, would alleviate early-stage non-freezing cold injury of the sciatic nerve. We established Wistar rat models of non-freezing cold injury by exposing the left sciatic nerve to cold (3–5°C) for 2 hours, then admin-istered dexamethasone (3 mg/kg intraperitoneally) to half of the models. One day after injury, the concentration of Evans blue tracer in the injured sciatic nerve of rats that received dexamethasone was notably lower than that in the injured sciatic nerve of rats that did not receive dexamethasone; neither Evans blue dye nor capillary stenosis was observed in the endoneurium, but myelinated nerve ifbers were markedly degenerated in the injured sciatic nerve of animals that received dexamethasone. After dexamethasone administration, however, endoneurial vasculopathy was markedly improved, although damage to the myelinated nerve ifber was not alleviated. These ifndings sug-gest that dexamethasone protects the blood-nerve barrier, but its beneift in non-freezing cold injury is limited to the vascular system.