鞘内注射硫酸镁和吗啡对切口痛大鼠脊髓背角p-αCaMK Ⅱ表达的影响

目的观察鞘内注射(it)硫酸镁(MgSO4)和吗啡对切口痛大鼠脊髓背角磷酸化钙—钙调蛋白依赖性蛋白激酶Ⅱα(p-αCaMKⅡ)表达的影响。方法所有大鼠术前8d鞘内置管,用机械缩足反射阈值、热缩足潜伏期和累计疼痛评分来评价大鼠疼痛行为学变化;用免疫组织化学和Western blot法来测定吗啡和硫酸镁对大鼠脊髓背角p-αCaMKⅡ表达的影响。结果术前或术后30minit吗啡5μg或MgSO4188μg和吗啡2.5μg使术后2h的机械性缩爪阈值(MWT)和热刺激缩爪阈值(TWL)明显延长(P<0.01),累积疼痛评分明显降低(P<0.01);术前30minitMgSO4375μg或吗啡5μg或MgSO4188μg和吗啡2.5μg使大鼠术后2h脊髓背角p-αCaMKⅡ表达明显减少(P<0.05)。结论在大鼠切口痛模型中,it吗啡5μg或MgSO4188μg和吗啡2.5μg具有确切的抗伤害作用,其抗伤害作用可能与抑制脊髓背角p-αCaMKⅡ表达有关。

Effects of intrathecal MgSO4 and morphine on spinal p-αCaMK Ⅱ in a rat model of incisional pain

Aim To observe the effect of intrathecal(it) MgSO4 and morphine on spinal phospho-calcium/calmodulin-dependent protein kinase Ⅱα(p-αCaMK Ⅱ) in a rat model of incisional pain.Methods Rats in all groups were intrathecally cathetered on 8 d before operation.Pain behavior at 2 h after incision was evaluated by mechanical withdrawal threshold(MWT) and thermal withdrawal latency(TWL) and a cumulative pain score.The expression of p-αCaMK Ⅱ was assessed by immunohistochemical method and Western blot analysis.Results In pre-incisional and post-incisional morphine 5 μg group and pre-incisional and post-incisional MgSO4 188 μg plus morphine 2.5 μg group,MWT and TWL increased significantly and cumulative pain scores decreased remarkably(P<0.01) 2 h after incision.In pre-incisional MgSO4 375 μg group and pre-incisional morphine 5 μg group and pre-incisional MgSO4 188 μg plus morphine 2.5 μg group,the expression of p-αCaMK Ⅱ was decreased significantly in spinal cord(P<0.05) 2 h after incision.Conclusions In a rat model of incisional pain,preemptive intrathecal morphine 5 μg and MgSO4 188 μg plus morphine 2.5 μg provided obviously antinociceptive effect,which might be associated with inhibition of the expression of p-αCaMK Ⅱ in spinal cord.