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目的 :探讨内皮依赖性舒张因子 (EDRF/NO)对听功能的保护作用及作用机制。方法 :36只豚鼠随机分为 4组 ,利用活体显微镜、电视摄像、计算机图像分析技术及螺旋韧带血管纹铺片、透射电镜技术 ,观察EDRF/NO对听功能的保护作用。同时 ,以听神经复合动作电位阈值 ,判断听力损伤程度 ,测定循环血液中超氧化物歧化酶(SOD)的浓度 ,以反映微循环血液中氧自由基的含量。结果 :①生理盐水组 ,耳蜗微循环的血流量在整个测试的 30min内保持稳定 ,听功能正常 ;②速尿组 (F组 ) ,经静脉注射药物后 ,耳蜗血流迅速下降 ,在用药 10min时 ,耳蜗血流下降达 5 6 % ,缺血的同时伴听力下降、耳蜗血管纹超微结构的损伤及循环SOD的下降 ,与用药前比较差异有显著性 ;③速尿 /L 精氨酸组 (F/L Arg组 ) ,EDRF/NO能使速尿引起的血流下降明显改善 ,听功能及耳蜗血管纹超微结构的损伤程度较单纯F组减轻 ,恢复正常功能的时间提前 ;④速尿 /L 硝基 精氨酸组 (F/L NNA组 ) ,耳蜗的缺血及听力损伤的程度均较F组加重 ,且恢复正常的时间延长。结论 :EDRF/NO能通过加快豚鼠内耳微循环的血流 ,增加局部血流的灌注 ,清除氧自由基而促进听功能的恢复
Objective: To investigate the protective effect and mechanism of endothelium-dependent relaxing factor (EDRF / NO) on auditory function. Methods: Thirty-six guinea pigs were randomly divided into 4 groups. The protective effect of EDRF / NO on the hearing function was observed by using live microscope, TV camera, computer image analysis technique and spiral ligament veins and transmission electron microscopy. At the same time, the auditory nerve complex action potential threshold to determine the degree of hearing impairment, determination of circulating blood superoxide dismutase (SOD) concentration to reflect the content of oxygen free radicals in the microcirculatory blood. Results: ① In normal saline group, cochlear microcirculation blood flow remained stable within 30 min of the whole test, and hearing function was normal; ② In furosemide group (F group), cochlear blood flow decreased rapidly after intravenous injection of drug, , The cochlear blood flow decreased by 56%, while accompanied by ischemic hearing loss, ultrastructure damage of the stria vascularis and the decline of circulating SOD, compared with before treatment, the difference was significant; ③ furosemide / L arginine (F / L Arg group), EDRF / NO can significantly reduce furosemide-induced blood flow decline, auditory function and cochlear stria vascularis ultrastructure damage than the simple F group to reduce the time to restore normal function; ④ Furosemide / L-nitroarginine group (F / L NNA group), the degree of cochlear ischemia and hearing impairment than F group aggravated, and returned to normal time. Conclusion: EDRF / NO can promote the recovery of auditory function by accelerating the blood flow of microcirculation in the inner ear of guinea pig, increasing the perfusion of local blood flow, scavenging oxygen free radicals