Lipman J M, Sokoloff L
Mech Ageing Dev. 1985 Oct 14;32(1):39-55. doi: 10.1016/0047-6374(85)90034-x.
Unscheduled DNA synthesis (UDS) was demonstrated both in fresh slices of rabbit articular cartilage and in resting chondrocytes dissociated from it. Uptake of [3H]thymidine by chondrocytes treated with 10 mM hydroxyurea and irradiated with 254 nm ultraviolet light (20 J/m2) was measured by autoradiography. The UDS in the resting chondrocytes was minuscule compared with that of chondrocytes growing in monolayer culture. It was greater in resting cells from 3- than in 18-month old rabbits but persisted in animals up to 52 months of age. In both resting and cultured chondrocytes, UDS was greatly inhibited by aphidicolin (5 micrograms/ml). The finding of age-related decrease in UDS of resting chondrocytes, contrasted with previously demonstrated lack of it in dividing ones, raises questions about in vitro artefacts in studies of cellular senescence.
在兔关节软骨新鲜切片以及从中分离出的静止软骨细胞中均证实了非程序性DNA合成（UDS）。通过放射自显影法测定了用10 mM羟基脲处理并经254 nm紫外线（20 J/m²）照射的软骨细胞对[³H]胸腺嘧啶核苷的摄取。与单层培养中生长的软骨细胞相比，静止软骨细胞中的UDS微不足道。3月龄兔子的静止细胞中的UDS比18月龄兔子的更大，但在高达52月龄的动物中仍持续存在。在静止和培养的软骨细胞中，UDS均受到放线菌素（5微克/毫升）的强烈抑制。静止软骨细胞UDS随年龄增长而下降的这一发现，与之前在分裂软骨细胞中未发现这种现象形成对比，这引发了关于细胞衰老研究中体外人工制品的问题。
