中等强度冲击波负压暴露对豚鼠耳蜗毛细胞游离钙浓度的影响

Effects of exposure to moderate blast underpressure on calcium ion of cochlea hair cells in guinea pig

目的:观察实验性冲击波负压(BUP)暴露对豚鼠耳蜗外毛细胞内游离钙浓度([Ca2+]i)的影响。方法:在激光共聚焦显微镜下,用钙敏荧光探针Fluo-3作为指示剂,观察豚鼠暴露中等强度实验性BUP后耳蜗外毛细胞[Ca2+]i的变化。结果:中等强度BUP暴露后8 h,至暴露后24 h和3 d稍有回落,但仍高于正常对照组。上述这些变化与听性脑干反应阈值的升高是一致的。结论:豚鼠暴露中等强度性BUP可引起耳蜗外毛细胞内[Ca2+]i的明显增高,且可能是听功能损害的主要原因之一。

Objective： To investigate the effects of exposure to blast underpressure（BUP） on intracellular free Ca^2＋ concentrations （[Ca^2＋]i） in outer hair cells（OHCs）. Methods：The guinea pigs were killed by decapitation following exposure to the moderate BLIP. [Ca^2＋]i in the OHCs was examined with Fluo - 3, a fluorescent probe for [Ca^2＋ ]i under laser scanning confoeal mieroscope（LSCM）. Results： The intensity of fluorescent [Ca^2＋]i increased two times as much as that in the control group following 8 hours exposure to BLIP. Compared with the control group, it still sustained at a higher level following 24 hours and three days exposure. The above changes were found to be consistent with the increase of auditory brainstem response（ABR） threshold. Conclusion： It is suggested that exposure to moderate experimental BUP can obviously increase the cOncentration of [Ca^2＋ ]i in OHCs of guinea pigs, which may be one of the main causes of hearing loss by exposure to blast underpressure.