细胞周期和细胞凋亡的改变在X线辐射损伤后皮肤愈合延迟中的作用

Effects of the changes of cell cycle and apoptosis on the wound healing after by X-ray radiation injury

目的 :探讨细胞周期紊乱和凋亡在X线辐射损伤后创伤愈合延迟中的作用。方法 :选用局部软X线辐射损伤合并创伤大鼠模型 ,应用病理形态观察、流式细胞术等方法观察不同时相点创面组织的病理改变、细胞周期及细胞凋亡的变化。结果 :组织病理观察表明 ,肉芽组织的结构不规则 ,胶原组织排列紊乱 ,胶原合成减少 ,创伤愈合延迟。在伤后 3d～ 9d时间段内 ,辐射侧G0 /G1 期细胞增加 ,S期和G2 /M期细胞减少 ,表明软X线局部照射后细胞发生了严重的G1 期阻滞。在伤后 1 3d～ 2 2d时间段内 ,辐射侧S期细胞逐渐增加 ,2 2d时达到峰值 ,大量的细胞停留在S期 ,S期显著延长。在 3d～ 9d时间段内 ,辐射侧伤口组织细胞凋亡增加 ,6d时达到峰值 ,之后逐渐减少。在创伤愈合的整个过程中 ,辐射侧的细胞凋亡呈由低到高再到低的时相变化。对照侧伤口组织细胞凋亡百分数在整个愈合过程中变化并不显著。结论

Objective: To explore the effects of the changes of cell cycle and apoptosis on wound healing induced by X ray radiation. Methods:An animal model was used for the experiment in which rats were subjected to local soft X ray radiation with wound trauma. The changes of morphology, cell cycles and apoptosis were analyzed by HE staining and flow cytometry, respectively. Results: An irregular structure of granulation tissue was observed. The synthesis of collagen decreased and its arrangement was disorder. During 3 9 days after the rats wounded, cells in G 0/G 1 phase in the site of radiation impaired wound increased significantly but cells in S and G 2/M phase decreased, which indicated a serious cell block in G 1 phase following local soft X ray radiation, whats more, cell apoptosis increased and reached the peak value on the 6 th day and then decreased. No significant change of apoptosis in the control side was observed during the whole process of wound healing. In the period of 13～22 days after the rats wounded cells in S phase increased and reached the peak value on the 22 nd day. As a result, a lot of cells were kept in S phase so that S phase extended dramatically. Conclusion:The changes of cell cycles and apoptosis might be the mechanisms of healing delay of the wound induced by X ray radiation.