黏菌素对小鼠神经传导速率及运动单元动作电位的影响

Effect of colistin on nerve conduction velocity and motor unit action potential in mice

为探讨黏菌素对小鼠感觉神经传导速率(SNCV)、运动神经传导速率(MNCV)及运动单元动作电位(MUAP)的影响,对50只昆明系小鼠单次尾静脉注射硫酸黏菌素7.5 mg.kg-1,每12 h 1次,连续给药7 d。分别于第1、3、7、14天(以初次给药当天为第1天计)测定小鼠坐骨神经SNCV、MNCV及MUAP,并对腓肠肌进行病理学检查。结果表明,与对照组相比,黏菌素给药3 d后,SNCV降低至(30.67±1.15)m.s-(1P<0.05)。给药7 d后,神经传导速率(NCV)显著降低,MNCV降低至(24.47±0.41)m.s-(1P<0.05),SNCV降低至(29.67±2.89)m.s-(1P<0.05);此外,腓肠肌MUAP降低至(0.26±0.0153)mV(P<0.05),运动单元动作电位持续时间(MUAPD)降低至(0.3±0.046)s(P<0.01)。表明黏菌素可影响小鼠的神经感觉及运动功能,并可导致小鼠肌肉无力。SNCV变化较为敏感,可作为黏菌素诱发神经毒性的早期诊断指标。

To investigate the toxic effect of colisUn on sensory and motor nerve conduction velocities （SNCV and MNCV）, motor unite action potentials （MUAP） and its duration （MUAPD） in adult mice, 50 mice were intravenously given 7.5 mg . kg-1 colistin in normal saline via tail vain twice a day for 7 days. On days 1, 3, 7 and 14 of the experiment, SNCV-, MNCV-, MUAP- and MUAPD -values were determined. The results showed that, compared with the control, after colistin was given for 3 d, SNCV was significantly decreased to 30.67±1.15 m-s1 （P〈0.05）; After colistin was given for 7 d, MNCV and SNCV were significantly decreased to （24.47±0.41） （P〈0.05） and （29.67±2.89） m-s-1 （P〈0.05）, respectively. In addition, MUAP and MUAPD of gastrocnemius muscle was significantly decreased to （0.26±0.015） mV （P〈0.05） and （0.3±0.046） s （P〈0.01）, respectively. The results revealed that colistin decreased the motor and sensory functions, and causedmuscle weakness of mice. The SNCV was more sensitive than others, and maybe helpful to detect colistin induced peripheral neurotoxicity.