Johansson O, Madsen K
Med Biol. 1987;65(1):57-60.
We have earlier demonstrated that human growth hormone stimulates DNA synthesis and proteoglycan production in cultured chondrocytes. The present study is concerned with the effects of somatostatin and other neuropeptides on cell proliferation by cultured rat rib growth plate chondrocytes. Chondrocytes were isolated from the growth plates by collagenase digestion and cultured as monolayers in multiwell plates. The cells were allowed to attach overnight and subsequently incubated for 24 h under serum-free conditions to establish growth arrest. Somatostatin and other peptides were then added and the cultures were incubated for 18 h. Finally, the cultures were labelled for 6 h with tritiated thymidine in the presence of peptide. For screening purposes, the effect on DNA-synthesis was assayed as incorporation of [3H]-thymidine into acid-insoluble material. For a more exact estimate, parallel cultures were prepared for autoradiography and the fraction of labelled nuclei was determined by counting. Among the peptides we tested (somatostatin, GRF, TRH, SP, mENK, PHI, VIP, hCT) only somatostatin had any discernible effect on DNA synthesis, with an apparently optimal effect at 10 fM. This concentration is well within the range found in various tissues in vivo and suggests a physiological role for somatostatin in chondrocyte growth regulation. Further experiments are required, however, to clarify by which mechanism somatostatin influences the cells and whether the peptide interacts with other growth factors such as the IGFs.
我们之前已证明，人生长激素可刺激培养的软骨细胞中的DNA合成及蛋白聚糖生成。本研究关注生长抑素及其他神经肽对培养的大鼠肋生长板软骨细胞增殖的影响。通过胶原酶消化从生长板分离软骨细胞，并在多孔板中作为单层细胞培养。让细胞贴壁过夜，随后在无血清条件下孵育24小时以建立生长停滞。然后加入生长抑素及其他肽，并将培养物再孵育18小时。最后，在存在肽的情况下用氚标记的胸腺嘧啶核苷对培养物进行6小时的标记。为进行筛选，将对DNA合成的影响测定为[3H] - 胸腺嘧啶核苷掺入酸不溶性物质中的量。为了更准确地估计，制备平行培养物用于放射自显影，并通过计数确定标记核的比例。在我们测试的肽（生长抑素、生长激素释放因子、促甲状腺激素释放激素、P物质、甲硫氨酸脑啡肽、PHI、血管活性肠肽、人降钙素）中，只有生长抑素对DNA合成有任何可察觉的影响，在10 fM时具有明显的最佳效果。该浓度完全在体内各种组织中发现的范围内，表明生长抑素在软骨细胞生长调节中具有生理作用。然而，需要进一步的实验来阐明生长抑素影响细胞的机制以及该肽是否与其他生长因子（如胰岛素样生长因子）相互作用。
