Role of sulfated glycoconjugates ectodermally derived hard tissue formation

用高铁二胺硫代氨基脲银蛋白(HID-TCH-SP)、酶消化法和~(35)S放射自显影技术，研究了成釉细胞和釉质基质中硫酸糖偶联物的超微结构分布和组织化学特性。HID-TCH-SP染色见于Tomes‘s突的交错细胞膜、大多数分泌颗粒内部和大鼠棱柱釉基质表层。该染色不仅抵抗睾丸透明质酸酶的酶消化，也抵抗肝素酶的酶消化。在发育中的Newt无棱柱牙釉质中，当釉质基质沉积到一定厚度后，第一层釉质基质呈球形，与牙基底膜并列，并倾向于与已沉积的牙本质基质混合。随后，釉质基质沉积在牙齿基底膜的外部(成釉蛋白)，形成真正的釉质基质。在混合基质中发现了这种染色，并被鉴定为硫酸软骨素；相反，真正的釉质基质中不含硫酸糖偶联物。虽然Newt牙本质和骨基质中含有很高浓度的35S，但在牙釉质基质中没有观察到放射性反应。在发育中的哺乳动物牙釉质表层，检测到大量的硫酸化糖偶联物，釉质蛋白的免疫标记明显较弱。现有的数据表明，在棱柱状釉质形成过程中，某些硫酸盐物质是必需的，可能是硫酸糖蛋白，但不是糖胺聚糖；因此，它们代表了系统发育的高级元素。

U1trastructural distribution and histochemical properties of sulfated glycoconjugates in ameloblasts and enamel matrices of rat and newt were investigated by use of the high iron diamine thiocarbohydrazide silver proteinate (HID-TCH-SP), enzymatic digestion methods, and 35S-autoradiography. The HID-TCH-SP staining was detected on the interdigitating cell membrane of Tomes' process, inside most secretory granules, and on the surface layer of rat prism enamel matrix. The staining resisted enzymatic digestion not only by testicular hyaluronidase but also by heparitinase. In the developing newt prismless enamel, after deposition of the mantle dentin matrix to a certain thickness, the first enamel matrix, globular in shape, appeared in juxtaposition to the dental basement membrane and tended to be intermixed with the previously deposited dentin matrix. Subsequently, enamel matrix was deposited outside (ameloblasticside) of the dental basement membrane and formed a true enamel matrix. The staining was found in the mixed matrix and was identified as chondroitin sulfate; in contrast, the true enamel matrix contained no sulfated glycoconjugates. Although newt dentin and bone matrices incorporated a very high concentration of 35S, no radioactive reaction was observed in enamel matrix. On the surface layer of developing mammalian enamel where large amounts of sulfated glycoconjugates were detected, immunolabelling of enamel protein was significantly weak. The data available suggest that certain sulfated substances, probably sulfated glycoproteins but not glycosaminoglycans, are required in the process of prismatic enamel formation; hence they represent phylogenetically advanced elements.