脊髓背角卡配因在大鼠足底炎性痛形成中的作用

目的 探讨脊髓背角卡配因在大鼠足底炎性痛形成中的作用.方法 雄性SD大鼠48只,6周龄,体重160～200 g,采用随机数字表法,将其随机分为3组:正常对照组(C组,n=8)、PBS组(n=16)和酵母多糖诱发足底炎性痛组(Z组,n=24).Z组于大鼠左侧后足足底皮下注射酵母多糖1.25 mg,制备酵母多糖诱发足底炎性痛模型,PBS组给予等容量PBS 100μl.分别于给药前(T0)、给药后30 min(T1)、1 h(T2)、2 h(T3)、4 h(T4)、8 h(T5)、24 h(T6)和48 h(T7)时测定左侧后足机械刺激缩足阈值(MWT)、热缩足反应潜伏期(PWTL)和左侧后足足底最大厚度.PBS组于T4时处死8只大鼠,Z组分别于T4、T6和T7时各处死8只大鼠,取左侧脊髓L4～6节段,采用Western blot法测定脊髓背角spectrin αⅡ降解产物、IκBα、环氧化酶-2(COX-2)的表达和NF-κB活性.结果 与C组比较,Z组MWT降低,PWTL缩短,足底最大厚度增厚,脊髓背角spectrin αⅡ降解产物和COX-2的表达上调,IκBα表达下调,NF-κB活性升高(P＜0.05或0.01),PBS组上述指标差异无统计学意义(P＞0.05).结论 脊髓背角卡配因活化参与了大鼠足底炎性痛的形成,其机制与激活NF-κB,上调COX-2表达有关.

Role of calpain in spinal dorsal horn in development of paw inflammatory pain in rats

Objective To investigate the role of calpain in the spinal dorsal horn in development of paw inflammatory pain in rats.Methods Forty-eight male SD rats,aged 6 weeks,weighing 160-200 g,were randomly divided into three groups:normal control group(group C,n =8),PBS group( n =16),zymosan-induced paw inflammatory pain group (group Z,n =24).Inflammatory pain was induced by injection of zymosan 1.25 mg into the plantar surface of left hindpaw.Group PBS received the equal volume of PBS 100 μl.The mechanical paw withdrawal threshold (MWT),paw withdrawal thermal latency (PWTL) and maximum thickness of the plantar surface of left hindpaw were measured before (T0 ) and at 30 min,1,2,4,8,24 and 48 h(T1-7 ) after zymosan or PBS injection.Eight rats were sacrificed at T4 in group PBS and at T4.6,7 in group Z respectively.The left lumbar segment (L4-6) was removed to determination of spectrin α Ⅱ breakdown products,IκBα,cyclooxygenase-2 (COX-2)expression and NF-κB activity in the spinal dorsal horn by Western blot.Results Compared with group C,MWT and PWTL were significantly decreased,maximum thickness of paw and NF-κB activity in the spinal dorsal horn were significantly increased,spectrin α Ⅱ breakdown products and COX-2 expression in the spinal dorsal horn were upregulated,while IκBα expression was down-regulated in group Z( P ＜ 0.05 or 0.01 ),but no significant change was found in group PBS( P ＞ 0.05).Conclusion The activation of calpain in the spinal dorsal horn is involved in the development of paw inflammatory pain in rats through activating NF-κB and up-regulating the expression of COX-2.