摘要
目的 观察水杨酸钠对豚鼠耳蜗外毛细胞 (outerhaircells,OHC)内游离钙浓度 [Ca2 + ]i的影响 ,并对钙通道调控药物的拮抗作用进行观察 ,以深入探讨水杨酸钠耳毒性的分子生物学机制。方法 豚鼠全身麻醉后断头活杀 ,酶 机械法分离获得耳蜗单离OHC。 10 μmol/L的Fluo 3/AM负载30min后用ACASUltima型激光扫描共聚焦显微镜观察不同药物灌流下OHC[Ca2 + ]i的变化。结果 OHC在标准细胞外液灌流过程中 [Ca2 + ]i保持稳定。 1mmol/L水杨酸钠灌流致 8/ 10个细胞的 [Ca2 + ]i明显升高。无钙细胞外液中灌流亦有 10 / 10个细胞 [Ca2 + ]i明显的升高。经 3mmol/L利多卡因作用1h后 ,水杨酸钠灌流不能使细胞 [Ca2 + ]i升高 (n =10 )。盐酸氟桂嗪可以明显阻断水杨酸钠导致的OHC[Ca2 + ]i升高效应 (3/ 12细胞的 [Ca2 + ]i升高 ) ,而尼莫地平无此效应 (7/ 7细胞的 [Ca2 + ]i升高 )。结论 水杨酸钠可以导致OHC[Ca2 + ]i明显增加 ,OHC[Ca2 + ]i升高来源于细胞内钙库的动员和释放。使细胞内 [Ca2 + ]i升高可能是水杨酸钠的耳毒性机制之一。
Objective In order to explore the mechanism of sodium salicylate ototoxicity the effect of sodium salicylate on intracellular Ca 2+ ([Ca 2+ ]i ) of the outer hair cells (OHCs) and the effects of calcium channel antagonist on sodium salicylate-induced [Ca 2+ ]i changes of the OHCs were examined Methods The OHCs of guinea pig cochlear were isolated using an enzyme-machine methods and loaded with 10 μmol/L Fluo-3/AM for 30 min at 37 ℃ Individual Fluo-3 loaded OHC was examined with a confocal microscope (ACAS Ultima, USA) using a 20 x objective lens and linear scan mean The fluorescent images, collected each 5-sec for 300 sec, were stored in a computer The fluorescent intensity of the OHCs were analyzed by the software cooperated with the confocal microscope, and a curve of fluorescent intensity changes trend against time was obtained Results The [Ca 2+ ]i of OHCs were steady under normal extracellular liquid perfusion Salicylate increased [Ca 2+ ]i in OHCs in calcium-free medium(10/10) and standard medium (8/10) 3 mmol/L lidocaine inhibited [Ca 2+ ]i increase in OHCs induced by salicylate(0/10) The [Ca 2+ ]i increase in OHCs induced by salicylate could be blocked by flunarizine(3/12) Nimodipin failed to block the [Ca 2+ ]i increase of OHCs induced by salicylate (7/7) Conclusion Sodium salicylate can result in [Ca 2+ ]i increase in OHC markedly,which may be due to the Ca 2+ release from intracellular calcium stores The effects of salicylate on[Ca 2+ ]i in OHCs might be one of the mechanisms of salicylate ototoxicity
出处
《中华耳鼻咽喉科杂志》
CSCD
2000年第4期263-266,I018,共4页
Chinese Journal of Otorhinolaryngology
基金
国家自然科学基金!资助项目 (39670 778)
军队杰出青年人才基金
关键词
耳蜗
外毛细胞
钙
水杨酸钠
豚鼠
Cochlea
Hair cells
outer
Calcium
Sodium salicylate
Lidocaine
Flunarizine
Nimodipine