Keratan sulfate epitopes exhibit a conserved distribution during joint development that remains undisclosed on the basis of glycosaminoglycan charge density
Keratan sulfate epitopes exhibit a conserved distribution during joint development that remains undisclosed on the basis of glycosaminoglycan charge density
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DOI：
10.1177/002215540205000806
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发表时间：
2002-08-01
影响因子：
3.2
通讯作者：
Pitsillides, AA
中科院分区：
文献类型：
--
作者：
Kavanagh, E;Osborne, AC;Pitsillides, AA
糖胺聚糖（GAG）含量和分布的变化对关节发育至关重要。然而，其确切性质尚未确定。我们已经使用免疫组织化学（IHC）和“临界电解质”阿尔新蓝染色，以评估这种变化，在发育中的鸡和兔关节。免疫组化显示鸡骺软骨中有硫酸软骨素标记，但在中间区没有。与此相反，突出的硫酸角质素（KS）标记仅限于鸡软骨间界面。在兔膝关节中，KS标记在假定的腔边界也很突出，但在区间和软骨中较弱。选择性预消化产生适当的标签损失和硫酸化不足的KS是不可检测的。通过扫描和积分显微光密度法对阿辛蓝染色进行定量，结果显示透明质酸样（HA样）间带染色突出，硫酸软骨素和较弱的KS染色仅限于骺软骨。透明质酸酶减少HA样染色的中间地带。令人惊讶的是，角蛋白酶还减少了中间区中的HA样染色，但不减少硫酸化GAG（sGAG样）染色。软骨素酶ABC对HA样染色几乎没有影响，但在所有区域中降低sGAG染色。兔关节间区也显示HA样染色，而非KS染色，骺软骨中显示强烈的硫酸软骨素样染色。我们的研究结果表明，限制KS分布在该地区接近推定的关节腔发育鸡和兔关节。阿辛蓝染色不能检测到该部分。因此，尽管组织化学允许相对不敏感的GAGS定量评估，但IHC增加了这些检测限。这对于KS尤其明显，KS在不同物种的关节中表现出免疫标记模式，这与软骨形成中的保守功能作用一致。
Changes in glycosaminoglycan (GAG) content and distribution are vital for joint development. However, their precise character has not been established. We have used immunohistochemistry (IHC) and "critical electrolyte" Alcian blue staining to assess such changes in developing chick and rabbit joints. IHC showed chondroitin sulfate labeling in chick epiphyseal cartilage but not in interzones. In contrast, prominent labeling for keratan sulfate (KS) was restricted to chick cartilage-interzone interfaces. In rabbit knees, KS labeling was also prominent at presumptive cavity borders, but weak in interzone and cartilage. Selective pre-digestion produced appropriate loss of label and undersulfated KS was undetectable. Quantification of Alcian blue staining by scanning and integrating microdensitometry showed prominent hyaluronan-like (HA-like) interzone staining, with chondroitin sulfate and weaker KS staining restricted to epiphyseal cartilage. Hyaluronidase decreased HA-like staining in the interzone. Surprisingly, keratanases also reduced HA-like but not sulfated GAG (sGAG-like) staining in the interzone. Chondroitinase ABC had little effect on HA-like staining but decreased sGAG staining in all regions. Rabbit joints also showed HA-like but not KS staining in the interzone and strong chondroitin sulfate-like staining in epiphyseal cartilage. Our findings show restricted KS distribution in the region close to the presumptive joint cavity of developing chick and rabbit joints. Alcian blue staining does not detect this moiety. Therefore, it appears that although histochemistry allows relatively insensitive quantitative assessment of GAGS, IHC increases these detection limits. This is particularly evident for KS, which exhibits immunolabeling patterns in joints from different species that is consistent with a conserved functional role in chondrogenesis.