庆大霉素及其代谢产物对外毛细胞内游离钙浓度的影响

Gentamicin and Its Metabolite Effect [Ca^(2+)]i in Isolated Outer Hair Cells

目的 探讨庆大霉素（ＧＭ）耳毒性与耳蜗外毛细胞（ＯＨＣ）内游离钙（［Ｃａ２＋］ ｉ）之间的关系。方法 离体耳蜗ＯＨＣ经钙荧光指示剂Ｆｌｕｏ－３负载后，用激光扫描共聚焦显微镜测定高钾溶液、ＧＭ、ＧＭ代谢产物等对ＯＨＣ［Ｃａ２＋］i的影响。结果ＧＭ使［Ｃａ２＋］i短暂下降，并阻滞高钾溶液引起的钙内流；ＧＭ代谢产物则使［Ｃａ２ ＋］ｉ持续升高，对高钾引起的钙内流无明显影响。结论 ＧＭ耳毒性与外毛细胞［Ｃａ２＋］i持续升高有关。

Objective To investigate the relationship between [Ca2 +]i and gentamicin ototoxicity. Methods Isolated outer hair cells were loaded with [Ca2 +]i - sensitive fluorescence dye Fluo- 3, and confocal laser microscopy was used to determine [Ca2 +]i when K +- Hanks、gentamicin or its metabolite were added. Results Gentamicin decreased [Ca2 +]i in short time, and inhibited inward calcium current induced by K + . On the contrary, metabolized gentamicin increased [Ca2 + ] i for a long period. It did not effect calcium current induced by K + . Conclusion Metabolized gentamicin increased [Ca2 + ]i, which may result in its ototoxicity.