Generation of highly-reactive oxygen species is closely related to hair cell damage in rat organ of Corti treated with gentamicin.
Generation of highly-reactive oxygen species is closely related to hair cell damage in rat organ of Corti treated with gentamicin.
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DOI：
10.1016/j.neuroscience.2009.02.085
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发表时间：
2009-06-16
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影响因子：
3.3
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中科院分区：
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活性氧（ROS）已被认为在氨基糖苷类药物诱导的毛细胞（HC）损失中起主要作用，但难以检测。此外，ROS可以正常发生在细胞中，它们在代谢、细胞信号传导和其他过程中发挥作用。两种新的探针，氨基苯基荧光素（APF）和羟苯基荧光素（HPF）是选择性检测高活性氧（hROS），那些最相关的细胞损伤的染料。我们评估了在体外慢性暴露于50 μ M庆大霉素期间新生大鼠Corti器官中hROS的存在，以检查HC类型和三个耳蜗转弯中细胞损伤与hROS之间的关系。hROS最初在48小时（h）检测到，在72小时增加，并持续至至少96小时。在48小时，hROS仅限于外部毛细胞，并发生在静纤毛丧失之前。在72 h时，外部HC显示hROS和静纤毛丢失，并且在少数内部HC中注意到hROS。基弯HC比中弯HC显示更多的hROS。即使在72 h时，在顶转中也观察到非常少的hROS积累或静纤毛损失。第一排外毛细胞最容易受到庆大霉素诱导的hROS的影响，其次是第二排和第三排外毛细胞。内部HC的行为类似于第三排外部HC。到96小时静纤毛损伤是广泛的，但存活的毛细胞显示持续的荧光。APF始终显示出比HPF更多的荧光。结果表明，hROS积累是庆大霉素诱导的HC损伤的重要初始步骤，并且Corti器官中HC的差异敏感性与hROS积累的差异密切相关。
Reactive oxygen species (ROS) have been suggested to play a major role in aminoglycoside-induced hair cell (HC) loss, but are difficult to detect. Moreover, ROS can occur normally in cells where they have roles in metabolism, cell signaling and other processes. Two new probes, aminophenyl fluorescein (APF) and hydroxyphenyl fluorescein (HPF) are dyes which selectively detect highly-reactive oxygen species (hROS), those most associated with cellular damage. We assessed the presence of hROS in the neonatal rat organ of Corti during chronic exposure to 50 μM gentamicin in vitro, to examine the relationship between cell damage and hROS across HC type and across the three cochlear turns. hROS were initially detected at 48 hours (h), with an increase at 72 h and persistence until at least 96 h. At 48 h, hROS were restricted to outer HCs and occurred prior to loss of stereocilia. At 72 h, outer HCs showed both hROS and stereocilia loss, and hROS were noted in a few inner HCs. Basal turn HCs showed more hROS than middle turn HCs. Very little hROS accumulation or stereocilia loss was observed in the apical turn, even at 72 h. First row outer HCs were most vulnerable to gentamicin-induced hROS, followed by second and then third row outer HCs. Inner HCs behaved similarly to third row outer HCs. By 96 h stereocilia damage was extensive, but surviving HCs showed persisting fluorescence. APF consistently showed more fluorescence than HPF. The results suggest that hROS accumulation is an important initial step in gentamicin-induced HC damage, and that the differential sensitivity of HCs in the organ of Corti is closely related to differences in hROS accumulation.