Oral Pathology Department, School of Dentistry, University of São Paulo, Av. Prof Lineu Prestes, 2227, Cidade Universitária CEP 05508-000, São Paulo, Brazil.
J Photochem Photobiol B. 2013 Sep 5;126:33-41. doi: 10.1016/j.jphotobiol.2013.06.011. Epub 2013 Jul 2.
Fractionation can improve photodynamic therapy (PDT) efficacy for potentially malignant oral lesion treatment. The aim of this study was to demonstrate the apoptosis/proliferation index of oral keratinocytes after two sessions of topical 5-ALA-mediated PDT in 4-Nitroquinoline-1-oxide-induced potentially malignant oral lesion, and to suggest the ideal interval between PDT sessions. Immuno-histochemical tests for proliferating cell nuclear antigen and caspase-3, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay were performed at 6h, 24h, 48h, and 72h time intervals after PDT. The number of positive cells showing caspase-3 expression was significantly higher, mainly at 6h after PDT. In the first cycle of PDT, the highest frequency of positive cells for TUNEL was found at 24h. At 72h after PDT, proliferating cell nuclear antigen positive cells increased significantly, indicating that there was an epithelial response in direction towards DNA repair and cell proliferation at this time. Because cell proliferation increases and cell death index decreases at 72h after PDT, it is recommended that the interval between the PDT sessions must not be longer than 2days up to total lesion remission.
分次治疗可提高光动力疗法（PDT）治疗潜在恶性口腔病变的疗效。本研究旨在探讨两次局部 5-氨基酮戊酸介导的 PDT 后，4-硝基喹啉-1-氧化物诱导的潜在恶性口腔病变中口腔角质形成细胞的凋亡/增殖指数，并提出 PDT 治疗间隔的理想时间。在 PDT 后 6h、24h、48h 和 72h 时间点进行增殖细胞核抗原和半胱天冬酶-3 的免疫组织化学检测以及末端脱氧核苷酸转移酶 dUTP 缺口末端标记（TUNEL）检测。显示半胱天冬酶-3 表达的阳性细胞数量明显更高，主要在 PDT 后 6h。在第一个 PDT 周期中，TUNEL 阳性细胞的最高频率出现在 24h。在 PDT 后 72h，增殖细胞核抗原阳性细胞显著增加，表明此时上皮细胞有向 DNA 修复和细胞增殖方向的反应。由于 PDT 后 72h 细胞增殖增加，细胞死亡指数降低，因此建议 PDT 治疗间隔不得超过 2 天，直至病变完全消退。
