瑞替加滨对布比卡因和氯普鲁卡因致小鼠惊厥半数有效剂量的影响

Effect of retigabine on median effective dose of bupivacaine and chloroprocaine for induction of convulsion in mice

目的通过探讨KCNQ2／3通道开放剂瑞替加滨对布比卡因和氯普鲁卡因致小鼠惊厥的半数有效剂量（ED50）的影响，研究KCNQ2／3通道与局麻药神经毒性的关系。方法清洁级雌性昆明种小鼠，体重20～30g。实验I采用随机数字表法将60只小鼠随机分为2组（n=30）：对照组（C组）和瑞替加滨组（R组），2组随机分为3个亚组，分别为不同剂量氯普鲁卡因组（C＋L1组、C＋L2组、C＋L3组和R＋L1组、R＋L2组和R＋L3组，n=10）。C组和R组腹腔注射0．9％生理盐水0．005ml／g或瑞替加滨20mg／kg，20min后腹腔注射氯普鲁卡因。C＋L1组、C＋L2组、C＋L3组氯普鲁卡因剂量分别为150．0、172．5、198．4mg／kg；R＋L1组、R＋L2组和R＋L3组氯普鲁卡因剂量分别为198．4、228．2、262．4mg／kg。实验Ⅱ采用随机数字表法将80只昆明小鼠随机分为2组（n=40）：对照组（C组）和瑞替加滨组（R组）。2组随机分为4个亚组，分别为不同剂量布比卡因组（C＋B1组、C＋B2组、C＋B3组、C＋B4组和R＋B1组、R＋B2组、R＋B3组、R＋B4组，n=10）。C组和R组腹腔注射0．9％生理盐水0．005ml／g或瑞替加滨20mg／kg，20min后腹腔注射布比卡因。C＋B1组、C＋B2组、C＋B3组、C＋B4组布比卡因剂量分别为37．8、43．5、50．0、57．5mg／kg；R＋B1组、R＋B2组、R＋B3组、R＋B4组布比卡因剂量分别为50．0、57．5、66．1、76．0mg／kg。采用Probit法计算布比卡因和氯普鲁卡因致小鼠惊厥的ED50及其95％可信区间。结果C组氯普鲁卡因致小鼠惊厥的ED50及其95％可信区间为165．3（155．8g／kg-175．0）mg／kg，布比卡因致小鼠惊厥的ED50及其95％可信区间为ED50为41．1（36．7～44．5）mg／kg。R组氯普鲁卡因致小鼠惊厥的ED50及其95％可信区间为212．4（200．2～224．3）mg／kg，布比卡因致小鼠惊厥的ED50及其95％可信区间为51．5（45．1～56．0）mg／kg。与C组比较，R组氯普鲁卡因和布比卡因致小鼠惊厥的ED50升高（P〈0．01）。结论KCNQ2／3通道开放剂瑞替加滨可明显提高氯普鲁卡因和布比卡因的致惊厥的ED50,降低氯普鲁卡因和布比卡因的致惊厥作用，提示局麻药的中枢神经毒性与其对KCNQ2／3通道抑制有关。

Objective To investigate the effect of KCNQ2/3 channel opener retigabine on the median ef- fective dose （ED50） of bupivaeaine and chloroproeaine for induction of convulsion in mice and the relationship be- tween KCNQ2/3 channels and the neurotoxicity of local anesthetics. Methods Pathogen-free female Kunming mice, weighing 20-30 g, were used in the study. The experiment was performed in two parts. Part [ Sixty mice were randomly divided into 2 groups （ n = 30 each） ： control group （group C） and retigabine group （group R）. The C and R groups were further divided into 3 subgroups with different doses of chlorprocaine （ C ＋ L1 , C ＋ L2 andC＋L3 groups, and R＋L1, R＋L2 andR＋L3 groups, n=10 each）. In groups C and R, 0.9% normal saline 0. 005 ml/g and retigabine 20 mg/kg were injected intraperitoneally, respectively, and chlorprocaine was injected intraperitoneally 20 min later. The doses of chlorprocaine were 150.0, 172.5 and 198.4 mg/kg in C ＋ L1 , C ＋ L2 and C ＋ L3 groups, respectively, and 198.4, 228.2 and 262.4 mg/kg in R ＋ L1, R ＋ L2 and R ＋ L3 groups, re- spectively. Part II Eighty mice were randomly divided into 2 groups （ n = 40 each） ： control group （group C） and retigabine group （group R）. The C and R groups were further divided into 4 subgroups with different doses of bupi- vacaine （C＋B1, C＋B2, C＋B3 and C＋B4 groups, and R＋BI, R＋B2, R＋B3 and R＋B4 groups, n= 10 each）. In groups C and R, 0.9% normal saline 0.005 ml/g and retigabine 20 mg/kg were injected intraperitone- ally, respectively, and bupivacaine was injected intraperitoneally 20 min later. The doses of bupivacaine were 37.8, 43.5, 50.0 and 57.5 mg/kg in C ＋ B1 , C ＋ B2, C ＋ B3 and C ＋ B4 groups, respectively, and 50.0, 57.5, 66.1 and 76.0 mg/kg in R ＋ B1 , R ＋ B2, R ＋ B3 and R ＋ B4 groups, respectively. The ED50 and 95% confidence interval （CI） of bupivacaine and chloroprocaine for induction of convulsion were calculated by Probit analysis. Results The ED50（95% CI） of chloroprocaine was 165.3 （155.8-175.0） mg/kg, and the ED5o（95% CI） of bupivacaine was 41.1 （36.7-44.5）mg/kg in C group. The EDs0 （95% CI） of chloroprocaine was 212.4 （200.2-224.3） mg/kg, and the ED50（95% CI）of bupivacaine was 51.5 （945.1-56.0）mg/kg in R group. Com- pared with group C, the EDso of bupivacaine and chloroprocaine for induction of convulsion was significantly in- creased in group R （ P 〈 0.01 ）. Conclusion KCNQ2/3 channel opener retigabine can significantly increase the ED50 of bupivacaine and chloroprocaine for induction of convulsion and reduce convulsion induced by bupivacaine and chloroprocaine in mice, indicating that the neurotoxicity of local anesthetics is related to inhibition of KCNQ2/ 3 channels.