Burk D T
J Craniofac Genet Dev Biol. 1985;5(4):385-98.
The role of hyaluronic acid (HA) in embryonic mouse nasal process outgrowth was assessed following administration of Streptomyces hyaluronidase, an enzyme that degrades HA. Enzyme-treated and control embryos were compared morphologically 4 and 24 hr after treatment on day 11 of gestation. After 4 hr the nasal processes of treated embryos were reduced in volume compared to controls. This size reduction was associated with a decrease in the amount of extracellular space in the nasal processes and a change in mesenchymal cell shape. Extracellular matrix material observed in controls included collagenlike fibers, 25-30-nm granules, and a delicate meshwork of 3-4-nm filaments. Basal laminae exhibited filamentous and granular material that extended to the surface of underlying cells. Similar matrix constituents were observed in treated embryos with the exception of the 3-4-nm filaments, which probably represent HA. By 24 hr after treatment, embryonic circulation had ceased and heart beat was slow. The nasal processes of these embryos were very small, but their configuration was such that fusion had often begun. Thus the presence of HA appears to be important in maintenance of the normal volume of the nasal processes and in maintenance of normal mesenchymal cell morphology, but other factors appear to contribute to the change in process shape requisite for fusion.
在给予能降解透明质酸（HA）的酶——链霉菌透明质酸酶后，评估了透明质酸在胚胎期小鼠鼻突生长中的作用。在妊娠第11天处理后4小时和24小时，对酶处理组和对照组胚胎进行形态学比较。处理后4小时，与对照组相比，处理组胚胎的鼻突体积减小。这种体积减小与鼻突细胞外间隙量的减少以及间充质细胞形状的改变有关。在对照组中观察到的细胞外基质物质包括类胶原纤维、25 - 30纳米的颗粒以及3 - 4纳米细丝构成的精细网络。基膜呈现出延伸至下层细胞表面的丝状和颗粒状物质。在处理组胚胎中观察到了类似的基质成分，但未观察到可能代表HA的3 - 4纳米细丝。处理后24小时，胚胎循环停止，心跳缓慢。这些胚胎的鼻突非常小，但其形态表明融合常常已经开始。因此，HA的存在似乎对于维持鼻突的正常体积以及维持正常的间充质细胞形态很重要，但其他因素似乎也有助于融合所需鼻突形状的改变。
