氯胺酮对CCI大鼠背根神经节GAP-43 mRNA表达的影响

Effect of ketamine on GAP-43 mRNA expression of doral root ganglion in rats with CCI

目的观察氯胺酮对坐骨神经慢性压迫损伤(CCI)模型大鼠背根神经节(DRG)生长相关蛋白(GAP-43)mRNA表达的影响。方法 36只成年雄性SD大鼠,体重180～220g,随机均分为三组。氯胺酮组(K组)和CCI组(C组)均采用CCI模型,假手术组(S组)仅暴露坐骨神经,不结扎。K组大鼠于CCI后3～14d每天腹腔注射氯胺酮10mg/kg,C组和S组腹腔注射等容量生理盐水。在术前(T0)、术后3d(T1)、7d(T2)、14d(T3)时测定机械痛阈和热痛阈值;T1～T3时测定痛阈后,每组随机取4只大鼠取腰段脊髓背根神经节(DRG)检测GAP-43mRNA的水平。结果与S组比较,K组和C组术后机械痛阈和热痛阈降低,GAP-43mRNA表达升高(P<0.05);与NP组比较,T2、T3时K组机械痛阈和热痛阈升高,GAP-43mRNA表达降低(P<0.05)。结论腹腔注射氯胺酮10mg/kg可减轻CCI大鼠疼痛,其机制可能与抑制DRG中GAP-43mRNA表达升高有关。

Objective To observe the effect of ketamine on growth associated protein （GAP）-43 mRNA expression of doral root ganglion （DGR） in rats with chronic constriction injury （CCI）. Methods Thirty-six adult male Sprague-Dawley rats,weighing 180-220 g,were equally randomized into 3 groups：ketamine group （K group）,CCI group （C group）,and sham operation group （S group）. CCI was performed in K and C groups,and the sciatic nerve was exposed but not ligated in S group. Rats in K group were intraperitoneally injected with ketamine 10 mg/kg daily at 3-14 d after CCI. Rats in C and S groups received the equal volume of saline. Mechanical and thermal pain thresholds were measured before operation （T0） and 3 （T1）,7 （T2）,14 d（T3） after CCI. After measuring pain thresholds at T1-3,DGR of lumbar spinal was obtained from 4 randomized rats in each group to determine the GAP-43 mRNA expression. Results Mechanical and thermal pain thresholds decreased,and GAP-43 mRNA of DRG increased in K and C groups compared with those in S group （P0.05）. Otherwise,mechanical and thermal pain thresholds increased and GAP-43 mRNA expression decreased at T2-3 in K group compared with those in C group （P0.05）. Conclusion Intraperitoneal ketamine 10mg/kg may mitigate pain in rats with CCI possibly via inhibiting the expression of upregulated GAP-43 mRNA in DGR.