复方亚甲蓝注射液浸润麻醉对小鼠痛阈的影响

Comparison of Anaesthetic Effect of HCl-Lidocaine and Methylene Blue Compound Injection in Mice

目的研究镇痛实验中以痛阈值作为检测麻醉效应指标的可行性及复方亚甲蓝注射液的镇痛效应。方法100只小鼠随机分为5组:生理盐水组、利多卡因组、复方亚甲蓝注射液高、中、低剂量组。将小鼠固定于掌心,两电极分别刺于小鼠尾尖1/3处及左下肢足部,开通测量仪(量程0.5~1 mA,阶程6),观察记录发生第一嘶叫反应的电流值,作为动物给药前之基础痛阈值。选用4#针头随机区组设计注射于小鼠足跟偏内上部胫骨周围间隙内,再按照基础痛阈测定同样抓取小鼠并同部位刺激,观察记录给药后10 min、30 min1、h2、h、4 h、6 h8、h1、0 h、12 h2、4 h2、6 h之第一嘶叫反应的电流值,以电流的变化值及实际电流值为观察指标。结果利多卡因给药后10min痛阈值即显著升至最高点,其后逐步降低,其测定痛阈值与基础痛阈值及生理盐水组的同点测定痛阈值比较有极显著性差异的维持时间2~3 h左右,4 h后基本无镇痛效应;利多卡因给药后10 min、30 min1、h2、h痛阈相对基础痛阈的变化值与生理盐水组的同点测定痛阈相对基础痛阈的变化值比较有极显著性差异,维持时间2~3 h左右,4 h后变化值无统计学的意义;药后2 h^26 h各复方亚甲蓝组动物的痛阈值与利多卡因组比较有极显著性差异(P<0.01或P<0.05)。结论2%利多卡因(0.05 mL/只)镇痛作用持续时间小于4 h,而0.33%1、.1%和3.3%的复方亚甲蓝镇痛作用持续10~26 h。结果证明复方亚甲蓝具有及时而持久的局部镇痛效应。

Objective To determine if methylene blue compound injection is a reliable anaesthetic approach in mouse experiments or not. Method 100 male and female Kunming mice were used in this study. Three groups of mice were given methylene blue injection to the plantar at 8.2, 27.5, 82.5 mg· kg^-1· d^-1 , respectively. The mice in the fourth group received 0.9% NaCI normal saline injection served as a normal control group and the fifth group of mice using lidocaine served as another control group. The pain threshold of mice was measured by a WQ - 9E pain threshold apparatus, at 10 min,30 min, 1 h,2 h,4 h, 6 h,8 h,10 h,12 h,24 h,26 h. after treatment. Results The peak analgesic effect at the injection site occurred at 10 minutes after administration of both lidocaine and compound methylene blue. There was a very significant diference （P 〈 0.01 ） between the pain threshold recorded in the drug treated groups and the saline control groups. The analgesic effect in the lidocaine-treated mice was maintained for 2 ～ 3 hours and disappeared at 4 hours after treatment. However, the annalgesic effect in the compound methylene blue-treated mice lasted for as long as 10 ～ 26 hours after treatment. Conclusion Our findings demonstrated that local analgesic effect induced by 0.33%, 1.1% and 3.3% compound methylene blue injection can be maintained for as long as 10 ～ 26 hours and is significantly longer than that induced by lidocaine.