人类眼前黏液反映表面生理变化。
Human preocular mucins reflect changes in surface physiology.
作者信息
Berry M, Ellingham R B, Corfield A P
机构信息
Division of Ophthalmology, University of Bristol, Bristol Eye Hospital, Lower Maudlin Street, Bristol BS1 2LX, UK.
出版信息
Br J Ophthalmol. 2004 Mar;88(3):377-83. doi: 10.1136/bjo.2003.026583.
BACKGROUND/AIMS: Mucin function is associated with both peptide core and glycosylation characteristics. The authors assessed whether structural alterations occurring during mucin residence in the tear film reflect changes in ocular surface physiology.
METHODS
Ocular surface mucus was collected from normal volunteers as N-acetyl cysteine (NAcCys) washes or directly from the speculum after cataract surgery. To assess the influence of surface health on mucins, NAcCys washings were also obtained from patients with symptoms, but no clinical signs of dry eye (symptomatics). Mucins were extracted in guanidine hydrochloride (GuHCl) with protease inhibitors. Buoyant density of mucin species, a correlate of glycosylation density, was followed by reactivity with anti-peptide core antibodies. Mucin hydrodynamic volume was assessed by gel filtration on Sepharose CL2B.
RESULTS
Surface fluid and mucus contained soluble forms of MUC1, MUC2, MUC4, and MUC5AC and also the same species requiring DTT solubilisation. Reactivity with antibodies to MUC2 and MUC5AC peaked at 1.3-1.5 g/ml in normals, while dominated by underglycosylated forms in symptomatics. Surface mucins were predominantly smaller than intracellular species. MUC2 size distributions were different in symptomatics and normals, while those of MUC5AC were similar in these two groups.
CONCLUSIONS
A reduction in surface mucin size indicates post-secretory cleavage. Dissimilarities in surface mucin glycosylation and individual MUC size distributions in symptomatics suggest changes in preocular mucin that might precede dry eye signs.
背景/目的：黏蛋白功能与肽核心及糖基化特征均相关。作者评估了黏蛋白在泪膜中留存期间发生的结构改变是否反映眼表生理学的变化。
方法
从正常志愿者收集眼表黏液，采用N - 乙酰半胱氨酸（NAcCys）冲洗法，或在白内障手术后直接从窥器采集。为评估表面健康状况对黏蛋白的影响，还从有症状但无干眼临床体征的患者（有症状者）获取NAcCys冲洗液。在含蛋白酶抑制剂的盐酸胍（GuHCl）中提取黏蛋白。通过与抗肽核心抗体反应追踪黏蛋白种类的浮力密度，其与糖基化密度相关。通过在琼脂糖CL2B上进行凝胶过滤评估黏蛋白的流体动力学体积。
结果
表面液体和黏液中含有可溶性形式的MUC1、MUC2、MUC4和MUC5AC，以及同样需要二硫苏糖醇（DTT）溶解的种类。正常情况下，与MUC2和MUC5AC抗体的反应性在1.3 - 1.5 g/ml时达到峰值，而在有症状者中以低糖基化形式为主。表面黏蛋白主要比细胞内种类小。有症状者和正常人中MUC2的大小分布不同，而MUC5AC在这两组中的大小分布相似。
结论
表面黏蛋白大小的减小表明分泌后裂解。有症状者中表面黏蛋白糖基化及单个MUC大小分布的差异表明眼前黏蛋白的变化可能先于干眼体征出现。
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