摘要
目的观察鞘内注射右美托咪定对背根节慢性受压痛大鼠(CCD)脊髓CaMKⅡ表达的影响,探讨右美托咪定-CaMKⅡ通路在大鼠背根节慢性受压痛中的作用。方法鞘内置管成功的雄性SD大鼠48只,随机分为6组,每组48只。分别是正常对照组(C组);模型组(CCD组);生理盐水组(NS组);右美托咪定2μg/kg组(Dex2);右美托咪定4μg/kg组(Dex4);右美托咪定8μg/kg组(Dex8)。分别于鞘内置管前(T1),制备CCD模型前(T2)、CCD模型制备后5d鞘内给药前(T3)、鞘内给药后30min(T4)、60min(T5)、120min(T6)、240min(T7)检测大鼠机械缩腿阈值(MWT)和热缩足潜伏期(TWL)。并于鞘内给药后240min,各组取4只大鼠处死,取脊髓腰膨大,采用免疫印迹法检测CaMKⅡ的表达。结果与C组比较,CCD组大鼠在T3~T7各时点MWT及TWL均显著降低,CCD组大鼠表现为明显的机械痛敏感和热痛敏感。NS组大鼠鞘内注射NS后对大鼠MWT及TWL无影响,鞘内注射不同剂量的右美托咪定则可显著提高CCD大鼠MWT和TWL。与C组(0.24±0.04)比较,CCD组(0.59±0.09)、NS组(0.61±0.08)大鼠CaMKⅡ蛋白表达均显著增加;鞘内注射不同剂量的右美托咪定后,大鼠脊髓CaMKⅡ蛋白表达(0.45±0.06、0.39±0.05、0.36±0.06)增加幅度显著降低。结论鞘内注射右美托咪定可减轻CCD大鼠机械痛敏感和热痛敏感,抑制CCD大鼠脊髓CaMKⅡ蛋白表达。
Objective To observe the effect of intrathecal injection dexmedetomidine and investigate the role of the T-type channel- CaMK Ⅱ in the spinal cord of the rats following chronic compression of dorsal root ganglia (CCD). Methods 48 male SD rats after intrathecal Indwelling catheter were divided into 6 groups (n= 8):Normal control group (C group) ;CCD model group (CCD group) ;Saline group (NS group) ;dexmedetomidine 2μg/kg group (Dex2) ;dexmedetomidine 4μg/kg group (Dex4) ;dexme- detomidine 8 μg/kg group (Dex8), Respectively. Mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) were measured at the following time point:before intrathecal Indwelling catheter(T1) ,before preparation of CCD model (T2) ,after 30 min (T4) ,60 min (T5) ,120 min (T6) ,240 min (T7) intrathecal administration. CaMK Ⅱ protein in the spinal of the rats (4 rats in every group) were detected with western blotting. Results Compared with the rats in C group,the MWT and TWL of the rats in CCD group significantly decreased. There were no difference of the MWT and TWL of the rats in NS group. Intrathecal injection different dosages of the dexmedetomidine can significantly improve MWT and TWL of the CCD rats. Conclusion Intrathecal injection dexmedetomidine can reduce the CCD rats MWT and TWL, down regulate the CaMKⅡ protein expression of the CCD rats.
出处
《重庆医学》
CAS
北大核心
2016年第34期4763-4765,共3页
Chongqing medicine