Milisen W B, Miller G K, Benjamin S A, Sibert G J
Collaborative Radiological Health Laboratory, Colorado State University, Fort Collins 80523.
In Vitro Cell Dev Biol. 1988 Oct;24(10):972-80. doi: 10.1007/BF02620868.
An explant culture procedure has been developed that makes it possible to measure the relative growth capacity of the epithelial and mesenchymal cells of the canine thymus gland. Standardized growth conditions were obtained by size-grading thymic fragments and counting to allow uniform fragment density during culture. After 6 d in culture, outgrowth from the fragments formed colonies that could be classified into epithelial, mixed, or spindle cell type. Uniform fragment size and number in each flask allowed calculation of the total plating efficiency, relative distribution of colony types, and mean colony diameters for thymic fragments collected from fetuses (50 d of gestation), neonates (0 d postpartum), and juveniles (70 d postpartum). Data show age-related changes in the proliferative capacity of the cells in all three colony types. The most significant difference was seen in the epithelium, which showed a 30% reduction in mean colony diameter over the 2 wk between fetal and neonatal ages and a 23% reduction over the postnatal period of 70 d. Significant reductions were seen in the other colony types as well. Because the severity of the effect of many injurious agents is proportional to the rate of growth of the target cells, these data suggest that the thymus gland of the fetus may be more sensitive to physical or chemical injury than is the neonate or adult.
已开发出一种外植体培养程序，该程序能够测量犬胸腺上皮细胞和间充质细胞的相对生长能力。通过对胸腺片段进行大小分级和计数来获得标准化的生长条件，以使培养过程中片段密度均匀。培养6天后，片段生长形成的集落可分为上皮型、混合型或梭形细胞型。每个培养瓶中片段大小和数量一致，从而能够计算从胎儿（妊娠50天）、新生儿（出生后0天）和幼年犬（出生后70天）采集的胸腺片段的总接种效率、集落类型的相对分布以及平均集落直径。数据显示，所有三种集落类型的细胞增殖能力均存在与年龄相关的变化。上皮细胞的变化最为显著，在胎儿期和新生儿期之间的2周内，平均集落直径减少了30%，在出生后70天内减少了23%。其他集落类型也出现了显著减少。由于许多损伤因子的作用严重程度与靶细胞的生长速率成正比，这些数据表明，胎儿的胸腺可能比新生儿或成年犬的胸腺对物理或化学损伤更敏感。
