Effects of alcohol dependence on expression of spinal neuronal K+-Cl-cotransporter 2 in rats / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effects of alcohol dependence (AD) on the expression of spinal neuronal K+-Cl cotransporter 2 (KCC2) in rats.Methods Forty-eight healthy male Sprague-Dawley rats,weighing 200-250 g,were randomly divided into 2 groups (n =24 each) using a random number tablecontrol group (group C) and group AD.An orogastric tube was inserted and alcohol was administered through the tube into the stomach to establish the model of AD.The concentration of ethanol was 5％,10％ and 20％ at 1st,2nd and 3rd weeks,respectively,and the concentration of ethanol was 35％ at 4th week and later.Alcohol was given at 10 ml · kg-1 · d-1,lasting for 8 weeks.The rats received drinking water containing no ethanol at 10 ml · kg-1 · d-1 instead of alcohol in group C.All the rats were allowed ad libitum access to food and water.Before the last administration,an elevated plus-maze test was performed for all the rats to observe their state of anxiety,which was used to evaluate the success of AD model.At the end of the last administration,the model of incisional pain was established.A 1-cm longitudinal incision was made through skin,fascia and muscle of the plantar aspect of the hindpaw in sevoflurane-anesthetized rats.At 2,6,24 and 48 h after operation,the mechanical and thermal paw withdrawal thresholds were measured.At 48 h after operation,the lumbar segment of the spinal cord was removed for determination of the expression of KCC2 by using immunofluorescence and Western blot.Results Compared with group C,the number of open arm entries was significantly reduced,the time spent on the open arms was shortened,the number of closed arm entries was increased,the time spent on the closed arms was prolonged,the mechanical and thermal paw withdrawal thresholds were decreased,and the expression of KCC2 was down-regulated in group AD.Conclusion Down-regulated expression of spinal neuronal KCC2 is involved in the mechanism of hyperalgesia in rats with AD.