摘要
目的 观察硫酸链霉素是否影响耳蜗螺旋神经节细胞 (spiralganglioncells,SGC)胞膜去极化时细胞内游离钙离子浓度 ([Ca2 + ]i)升高的能力 ,并观察这种影响在不同药物浓度下以及相同药物浓度对蜗轴不同部位的螺旋神经节细胞的作用的异同 ,旨在深入探讨硫酸链霉素急性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 机械法分离获得单离的SGC。 10 μmol L的钙敏荧光探针Fluo 3 AM负载 30min后用ACASUltima型激光扫描共聚焦显微镜观察各种条件下SGC[Ca2 + ]i的动态变化。结果 ①SGC[Ca2 + ]i在标准细胞外液灌流过程中保持稳定。② 15 0mmol L的高钾细胞外液灌流导致 12 14个细胞的 [Ca2 + ]i明显升高 ,而高钾无钙细胞外液灌流仅有 1 10个细胞[Ca2 + ]i 明显的升高。③经 1mmol L、0 .1mmol L、0 .0 1mmol L硫酸链霉素作用后 ,再灌流高钾细胞外液则分别有 0 9、6 14、7 13个细胞 [Ca2 + ]i 升高。④经 0 .0 2mmol L硫酸链霉素作用后 ,对来源于顶回和底回的SGC灌流高钾细胞外液分别有 5 10和 0 15个细胞 [Ca2 + ]i 升高。结论 高钾细胞外液灌流SGC[Ca2 + ]i 明显升高 ,钙升高的来源为细胞外钙离子的内流。硫酸链霉素可以阻断这种钙离子的内流 ,其阻断作用具有浓度和部位依赖性。
Objective To examine the effect of streptomycin on the calcium influx in spiral ganglion cells (SGCs) during depolarization and the differences among different concentrations of streptomycin and SGCs sources with the aim of exploring the mechanism of acute streptomycin ototoxicity. Methods The SGCs of guinea pig cochlea were isolated using an enzyme machine method and loaded with 10μmol/L Fluo 3/AM for 30 min at 37℃. Dissociated SGCs loaded with Fluo 3 were examined with a confocal microscope (ACAS Ultima, USA) using a 20 x objective lens and linear scan mean. The fluorescent images collected every 5 sec for a total of 300 sec were stored in a computer. The fluorescent intensity of the images was analyzed by a software cooperated with the confocal microscope, and a curve of fluorescent intensity changes against time was obtained. Results The [Ca 2+ ] i of SGCs was steady under the perfusion with standard extracellular solution. The [Ca 2+ ] i of SGCs increased in 12/14 cells under the perfusion with 150 mmol/L high potassium solution, but increased in only 1/10 cells induced by the high potassium calcium free solution. After treating with 1 mmol/L, 0.1 mmol/L, 0.01 mmol/L streptomycin, the [Ca 2+ ] i of the SGCs perfused with the potassium solution was increased in 0/9, 6/14, 7/13 cells, respectively. After the SGCs were treatment with 0.02 mmol/L streptomycin, the [Ca 2+ ] i of the SGCs perfused with the high potassium solution was increased in 5/10 SGCs from the apical turn and in 0/15 SGCs from the basal turn. Conclusion Perfusion with high potassium media can result in obviously increased [Ca 2+ ] i of the SGCs,and the increase of the [Ca 2+ ] i in the SGCs may originate from the extracellular calcium influx. The calcium influx can be blocked by streptomycin and such effects depend on streptomycin concentrations and SGCs sources.
出处
《中华耳鼻咽喉科杂志》
CSCD
北大核心
2001年第2期105-108,T004,共5页
Chinese Journal of Otorhinolaryngology
基金
国家自然科学基金!资助项目 ( 3 9670 778)
军队杰出青年人才基金!资助课题
