Zhang C Z, Li H, Bartold P M, Young W G, Waters M J
Department of Dentistry, University of Queensland, Brisbane, Australia.
J Dent Res. 1995 Oct;74(10):1636-43. doi: 10.1177/00220345950740100301.
Previous studies have shown that growth hormone can influence the expression of N-acetylgalactosamine-containing molecules in the extracellular matrix of developing rat incisors. N-acetylgalactosamine is a principal component of proteoglycans containing chondroitin sulfate and dermatan sulfate, as well as of some glycoproteins. Since chondroitin sulfate proteoglycans are identifiable components in enamel, dentin, and cementum, we have tested the hypothesis that growth hormone modulates their expression in developing rat incisors. The distribution of the chondroitin-sulfate-rich proteoglycans, decorin and biglycan, was investigated. We used the Lewis dwarf rat as a model because their circulating growth hormone levels are markedly reduced. Polyclonal antibodies against decorin and biglycan were used to localize these two proteoglycans. Semi-quantitative assessments of the staining patterns and intensities were made for each proteoglycan within compartments of the developing teeth. In normal Lewis rats, decorin and biglycan differentially expressed throughout the enamel organ, dental papilla, and dental follicle. Decorin displayed a wide distribution throughout all three regions and was closely associated with different cellular components. In contrast, biglycan showed little association with cells and was identified in the predentin and osteoid matrices. The expression of both proteoglycans was dramatically decreased in the growth-hormone-deficient animals. Administration of growth hormone to the dwarf rats markedly elevated the expression of both proteoglycans, approximating the distribution and intensity of staining seen in normal animals. These findings confirm that growth hormone status can modulate the expression of decorin and biglycan, and hence matrix deposition, in the rat tooth.
以往的研究表明，生长激素可影响发育中大鼠切牙细胞外基质中含N - 乙酰半乳糖胺分子的表达。N - 乙酰半乳糖胺是含硫酸软骨素和硫酸皮肤素的蛋白聚糖以及一些糖蛋白的主要成分。由于硫酸软骨素蛋白聚糖是釉质、牙本质和牙骨质中可识别的成分，我们检验了生长激素调节其在发育中大鼠切牙中表达的假说。研究了富含硫酸软骨素的蛋白聚糖饰胶蛋白聚糖和双糖链蛋白聚糖的分布。我们使用刘易斯侏儒大鼠作为模型，因为它们的循环生长激素水平显著降低。使用针对饰胶蛋白聚糖和双糖链蛋白聚糖的多克隆抗体来定位这两种蛋白聚糖。对发育中牙齿各部分内的每种蛋白聚糖的染色模式和强度进行了半定量评估。在正常刘易斯大鼠中，饰胶蛋白聚糖和双糖链蛋白聚糖在整个釉器、牙乳头和牙囊中有差异表达。饰胶蛋白聚糖在所有三个区域均广泛分布，并与不同的细胞成分密切相关。相比之下，双糖链蛋白聚糖与细胞的关联较少，在前期牙本质和类骨质基质中被识别。在生长激素缺乏的动物中，两种蛋白聚糖的表达均显著降低。给侏儒大鼠注射生长激素显著提高了两种蛋白聚糖的表达，接近正常动物中观察到的染色分布和强度。这些发现证实，生长激素状态可调节大鼠牙齿中饰胶蛋白聚糖和双糖链蛋白聚糖的表达，从而调节基质沉积。
