摘要: |
目的:探讨耳蜗外淋巴液(PL)-脑脊液(CSF) 屏障存在的直接证据。方法:以内源性激素氢化可的松(HC)和外源性激素甲泼尼龙(MP)为示踪剂,应用HPLC技术观察示踪剂在鼓阶外淋巴液(PST) 、前庭阶外淋巴液(PSV) 、中阶内淋巴液(SME) 、CSF以及血液中的动力学变化特征。结果:鼓室内注射HC 1 h 后,PST 和PSV 中HC浓度几乎完全相同;注射后1-2 h,PST,PSV中HC浓度同步快速降低;2-6 h期间,HC浓度降幅趋缓;而CSF 中HC浓度为0。鼓室内注射MP后,很快同时出现在PST 和PSV 中,两阶PL各时间测值差异不显著;CSF 中MP为0。SME 中HC和MP的各时间测值均显著高于PSV,PST 。结论:耳蜗小管不存在开放性自由通道使PST 与CSF 直接沟通, CSF亦不能经耳蜗小管直接进入鼓阶替换或取代PL,提示存在耳蜗PL- CSF屏障。 |
关键词: 耳蜗小管 外淋巴液 脑脊液 屏障 |
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Perilymph-cerebrospinal fluid barrier in guinea pig cochlea: a high-performance liquid chromatographic study |
孙爱华 |
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Abstract: |
Objective: To seek evidence for perilymph- cerebrospinal fluid barrier (CSF). Methods: A well-controlled comprehensive comparison of kinetics of hydrocortisone (HC) and methylprednisolone (MP) in perilymph of scala tympani (PST), perilymph of scala vestibuli (PSV), scala media endolymph (SME), CSF and plasma was made in guinea pigs. Results: One hour post intratympanic injection, the mean HC concentrations were exactly the same for both the PST and PSV. The concentrations in the two cochlear partions rapidly decreased from 1 h to 2 h post injection. Thereafter it decreased gradually. HC concentration was undetectable in CSF following direct intratympanic application. Likewise, topical application of MP resulted in the rapid appearance of the substance in both the PST and PSV. The mean value of MP concentration in PSV were similar to those in PSV. There was no significant difference in MP concentrations between the PST and PSV although there appeared to be a trend at 1, 2 and 6 h for concentrations to be greater in PSV than in PST. No detectable concentration of MP in CSF was observed after intratympanic administration. Both the HC and MP levels were significantly higher in SME than in the two perilymphatic compartments throughout the experiment. Conclusion: The findings of the experiment indicate that there is no open communication via the cochlear aqueduct that would allow PST to enter CSF. The CSF cannot directly enter the scala tympani via the cochlear aqueduct, displace and ultimately replace PST. Accordingly, the present study confirms the presence of a tight perilymph-CSF barrier. |
Key words: cochlear aqueduct perilymph cerebrospinal fluid barrier |