Delanian S, Martin M, Bravard A, Luccioni C, Lefaix J L
Service d'Oncologie-Radiothérapie, Hôpital Saint-Louis, APHP, Paris, France.
Radiother Oncol. 1998 Jun;47(3):255-61. doi: 10.1016/s0167-8140(97)00195-3.
The pathophysiological aspects of radiation-induced fibrosis (RIF) have not been well characterized. We therefore cultured human fibroblasts from samples of skin with RIF to investigate the long-term effects of therapeutic irradiation.
Biopsies of normal and RIF skin were obtained from patients previously irradiated for cancer, without recurrence. Cells were extracted from dermis samples by the outgrowth technique, seeded as monolayers and cultured at confluence. Enzyme activities and proteins were assayed, RNA was isolated and Northern blot analysis was performed on surviving cells between passages 2 and 5.
RIF cell cultures displayed heterogeneous fibroblasts populations. The initial outgrowth consisted of one-third small cells that floated rapidly, one-third spindle-shaped cells migrating far from the explant to form islets and one-third large pleiomorphic cells. In subsequent subcultures, surviving cells exhibited either myofibroblastic characteristics with a normal proliferative capacity or senescent morphology with a reduced proliferative capacity. These RIF cells had a brief finite lifespan, with dramatically reduced growth rate during their initial outgrowth and the following passages. Study of the antioxidant metabolism showed that Mn superoxide dismutase and catalase activities were significantly weaker in surviving RIF cells than healthy fibroblasts. These exhausted RIF cells exhibited no overexpression of transforming growth factor beta or tissue inhibitor of metalloproteinase.
Irradiation may lead to apparently contradictory effects such as fibrosis and necrosis in clinical practice. In cell culture, we observed two main cellular phenotypes which may be related to both processes, i.e. myofibroblast-like cells and fibrocyte-like cells. These two phenotypes may represent two steps in the differentiation induced as a long-term effect of therapeutic irradiation of the skin. Cell culture probably accelerates the induction of the terminal differentiation in RIF fibroblasts.
辐射诱导性纤维化（RIF）的病理生理学方面尚未得到充分阐明。因此，我们从患有RIF的皮肤样本中培养人成纤维细胞，以研究治疗性照射的长期影响。
从先前因癌症接受过照射且无复发的患者身上获取正常皮肤和RIF皮肤的活检样本。通过生长法从真皮样本中提取细胞，接种为单层细胞并在汇合状态下培养。测定酶活性和蛋白质，分离RNA，并对第2至5代存活细胞进行Northern印迹分析。
RIF细胞培养显示出异质性的成纤维细胞群体。最初生长的细胞由三分之一快速漂浮的小细胞、三分之一从外植体迁移很远形成小岛的纺锤形细胞和三分之一大的多形性细胞组成。在随后的传代培养中，存活细胞表现出具有正常增殖能力的肌成纤维细胞特征或具有降低增殖能力的衰老形态。这些RIF细胞寿命有限，在其最初生长和随后传代过程中生长速率显著降低。对抗氧化代谢的研究表明，存活的RIF细胞中锰超氧化物歧化酶和过氧化氢酶活性明显低于健康成纤维细胞。这些耗尽的RIF细胞未表现出转化生长因子β或金属蛋白酶组织抑制剂的过表达。
在临床实践中，照射可能导致纤维化和坏死等明显矛盾的效应。在细胞培养中，我们观察到两种主要的细胞表型可能与这两个过程都相关，即肌成纤维细胞样细胞和纤维细胞样细胞。这两种表型可能代表皮肤治疗性照射长期效应诱导的分化过程中的两个步骤。细胞培养可能加速了RIF成纤维细胞终末分化的诱导。
