Romagnoli P, Mancini G, Galeotti F, Francini E, Pierleoni P
Department of Human Anatomy and Histology, Section E. Allara Firenze, Italy.
J Dent Res. 1990 Dec;69(12):1857-62. doi: 10.1177/00220345900690121301.
The involution of crown odontoblasts after primary dentinogenesis in teeth of limited eruption is discussed. The odontoblasts of rat first lower molars were analyzed morphometrically from the tenth day to the 40th day of age, i.e., from the late phase of primary dentinogenesis to complete eruption. All the organelles underwent atrophy, but at different rates. In particular, the membranes of the endoplasmic reticulum decreased progressively in surface area from day 10 to day 40, whereas those of the Golgi apparatus decreased significantly between day 10 and day 14, and then remained practically unchanged in size. The volume of the lysosome compartment never increased beyond that during primary dentinogenesis. The profile length of the endoplasmic reticulum in each observed cell section was taken as an estimate of secretory activity. At day 40, this organelle was smaller in approximately 95% of the cells than it had been in any cell at day 10. These results suggest that cell atrophy may occur without any increase in the degradation processes of the cytoplasmic components and that the organelles along the secretory pathway may have independent regulatory systems. In the odontoblasts, as in several types of secretory epithelial cells, only a small fraction of the cells is engaged in appreciable secretory activity. This occurs, however, when the overall activity of the same cell population is relatively low.
本文讨论了有限萌出牙在原发性牙本质形成后冠部成牙本质细胞的退化。对大鼠第一下磨牙的成牙本质细胞从出生后第10天到第40天进行形态计量分析，即从原发性牙本质形成后期到完全萌出阶段。所有细胞器均发生萎缩，但速率不同。特别是，从第10天到第40天，内质网的膜表面积逐渐减少，而高尔基体的膜在第10天到第14天显著减少，然后大小基本保持不变。溶酶体区室的体积从未超过原发性牙本质形成期间的体积。每个观察到的细胞切片中内质网的轮廓长度被用作分泌活性的估计值。在第40天，约95%的细胞中的这种细胞器比第10天任何细胞中的都小。这些结果表明，细胞萎缩可能在细胞质成分降解过程没有任何增加的情况下发生，并且沿分泌途径的细胞器可能具有独立的调节系统。在成牙本质细胞中，与几种类型的分泌上皮细胞一样，只有一小部分细胞进行明显的分泌活动。然而，这发生在同一细胞群体的整体活性相对较低时。
