脊髓钙-钙调素依赖性蛋白激酶Ⅱ在小鼠慢性炎性痛中的作用

目的 探讨脊髓钙-钙调素依赖性蛋白激酶Ⅱ(CaMKⅡ)在小鼠慢性炎性痛中的作用.方法 雄性ICR小鼠40只,体重20～25 g,随机分为5组(n=8),正常对照组(A组)、慢性炎性痛组(B组)、KN92组(C组)、KN93 30 nmol组(D组)和KN93 45 nmol组(E组).B组～E组均采用小鼠左足背皮下注射完全Freund佐剂(CFA)20 μl的方法 制备慢性炎性痛模型.A组皮下注射生理盐水20μl.于CFA注射后1 d和3 d时D组、E组和C组分别鞘内注射CaMKⅡ特异性抑制剂KN93 30 nmol、45 nmol 和KN92(KN93无药理活性结构类似物)45 nmol,容量均为5μl.于CFA注射前30 min(基础状态)、注射后1 d且鞘内给药前(T1)及给药后30 min(T2)、注射后3 d且鞘内给药后30 min(T3)时测定痛阈.于最后1次痛阈测定结束后处死小鼠,取腰段脊髓组织采用Western blot法测定脊髓p-CaMKⅡα的表达水平.结果 与基础值和A组比较,B组、C组和D组T1～3时机械痛阈和热痛阈降低,脊髓p-CaMKⅡα表达上调;E组T1时机械痛阈和热痛阈降低,T2,3时机械痛阈、热痛阈和脊髓p-CaMKⅡα表达水平差异无统计学意义(P＞0.05).与B组比较,E组T2,3时机械痛阈、热痛阈升高,脊髓p-CaMKⅡα表达下调(P＜0.05).结论 脊髓CaMKⅡ参与了小鼠慢性炎性痛的形成.

Role of Ca2+/calmodulin-dependent protein kinaseⅡin chronic inflamnmtory pain in mice

Objective To investigate the role of ca2+/calmodulin-dependent protein kinase II(CaMKII)in chronic inflammatory pain in mice.Methods Forty healthy male ICR mice weighing 20-25 g were randomly divided into 5 groups(n=8 each):group A control;group B chronic inflammation;group C KN92:group D KN93 30 nmol and group E KN93 45 nmo1.Chronic inflammatory pain was produced by injecting complete Freund's adjuvant(CFA) 20 ul into the dorsal surface of left hind paw in group B,C,D and E.In group A normal saline 20 ul was injected instead of CFA.On the 1st and 3rd day after CFA injection group D,E and Creceived intrathecal administration of specific CaMK Ⅱ inhibitor KN93 30 and 45 nmol and KN92 45 nmol(aninactive analog of KN93).in 5 ul respectively.Mechanical and thermal pain threshold to von Frey hair and radiantheat stimulation were determined at 30 min before CFA injection (To,baseline),30 min before(T1) and 30 min after IT.administration (T2) on the 1st day after CFA injection and at 30 min after IT administration(T3) on the 3rd day after CFA injection.The mice were immediately killed by C02 anesthesia after the last determination of pain threshold.The lumbar segment of the spinal cord Was then removed for determination of the expression of p-CaMK Ⅱ a by Western blotting.Results The thermal and mechanical pain threshold Was significantly decreasedat T1-3 in group B,C and D but only at T1 in group E as compared with the baseline values and group A.Thermal and mechanical pain threshold were significantly hisher at T2.3 in group E than in group B.p-CaMKⅡa expression in the spinal cord was significantly higher in group B,C and D than in group A but there was no significant difference in p-CaMKⅡa between group A and E.The p-CaMKII a expression in the spinal cord was significantyly lower in group E than in group B.Conclusion CaMK Ⅱ is involved in the development of chronic inflammatory pain.