Impaired wound healing after local soft X-ray irradiation in rat skin: Time course study of pathology, proliferation, cell cycle, and apoptosis
Impaired wound healing after local soft X-ray irradiation in rat skin: Time course study of pathology, proliferation, cell cycle, and apoptosis
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DOI：
10.1097/01.ta.0000177674.55388.40
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发表时间：
2005-09-01
影响因子：
--
通讯作者：
Zhou, YG
中科院分区：
文献类型：
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作者：
Liu, X;Liu, JZ;Zhou, YG
背景。软x线照射在临床上通常用于治疗皮肤相关疾病，但其对伤口愈合的影响尚未得到很好的阐明。本研究的目的是建立局部软x线照射大鼠伤口愈合模型，并阐明辐射影响愈合的可能细胞机制。局部照射后切除大鼠背部全层、直径2 cm的皮肤组织。记录剂量效应曲线，5只521rad剂量照射动物于伤后第3、6、9、15天死亡，5只愈合进行组织学检查（苏木精和伊红染色）、细胞增殖（5-溴-2′-脱氧尿苷[BrdU]掺入）、细胞凋亡（和末端脱氧核苷酸转移酶生物素- dutp nick末端标记法[TUNEL]）和细胞周期（流式细胞术）。结果：软x线照射使创面愈合时间呈s型曲线延迟，剂量超过700 rad的创面在40 d内未愈合。这一剂量效应范围远低于伽马射线和硬x射线照射。对照创面在第3 - 9天有明显的brdu阳性标记，在整个愈合过程中有少量的tunel阳性标记，与对照创面相比，辐照创面在第3 - 9天有较少的brdu阳性标记和显著的tunel阳性标记，但在第15天有更多的brdu阳性标记和类似的tunel阳性标记。流式细胞术研究发现，与对照组相比，辐照创面中G(0)/G(1)期细胞比例较高（3-9天），S期细胞比例先低（3-9天）后高（13-22天），G(2)/M期细胞比例持续较低（整个愈合过程）。局部软x线照射能以剂量依赖的方式延迟伤口愈合，并显示出比伽马和硬x线照射更有效的生物效应。辐射诱导的非活性细胞增殖、活性细胞凋亡和3 - 9天的细胞周期阻滞可能是导致伤口愈合延迟的细胞机制之一。
Background. Soft x-ray irradiation is usually used to treat skin-related disease in the clinic, but its effect on wound healing has not been well elucidated. The purpose of our study was to develop a wound-healing model of local soft x-ray irradiation on rats and to clarify the possible cellular mechanisms through which radiation may influence healing.Methods. Full-thickness, 2-cm-diameter, dorsal cutaneous tissue was excised after local irradiation in rats. The dose-effect curve was recorded, and five animals irradiated with doses of 521 rad were killed at postwound days 3, 6, 9, and 15 and five were healed for histologic examination (hematoxylin and eosin staining), cell proliferation (5-bromo-2'-deoxyuridine [BrdU] incorporation), apoptosis (and terminal deoxynucleotidyl transferase biotin-dUTP nick end-labeling [TUNEL] method), and the cell cycle (flow cytometry).Results: Soft x-ray irradiation delayed wound-healing time with an S-like curve, and the wounds that received doses in excess of 700 rad failed to heal within 40 days. This dose-effect range is far below that of gamma and hard x-ray irradiation. Relative to control wounds, which contained prominent BrdU-positive labeling at days 3 through 9 and minimal TUNEL-positive labeling during the entire healing, the irradiated wounds had less BrdU-positive labeling and significant TUNEL-positive labeling at days 3 through 9 but more BrdU-positive labeling and similar TUNEL-positive labeling at day 15. Flow cytometry studies found a higher proportion of G(0)/G(1) phase cells (days 3-9), a lower (days 3-9) then higher (days 13-22) proportion of S phase cells, and a persistent lower proportion of G(2)/M phase cells (during the entire healing process) in the irradiated wounds compared with the controls.Conclusion. Local soft x-ray irradiation could delay wound healing in a dose-dependent manner and shows a more effective biological effect than that of gamma and hard x-ray irradiation. Radiation-induced inactive cell proliferation, active cell apoptosis, and arrested cell cycle at days 3 through 9 may be one of the cellular mechanism responsible for delayed wound healing.