Application of 5-aminorevulinic acid for diagnosis and treatment of oral cancer

本研究旨在探讨5-氨基丁酸(ALA)在口腔癌诊断和治疗中的应用。从生化角度分析了自体荧光与AL.A诱导荧光的关系，并从组织学角度评价了AIA光动力疗法对裸鼠肿瘤的治疗效果。据报道，在人类口腔癌中产生的自体荧光与原卟啉有关，在仓鼠和口腔癌细胞系诱导的口腔癌中也观察到类似的多卟啉。ALA局部或全身给药后，在口腔粘膜和诱发的金黄地鼠口腔粘膜中观察到类似于人类自身荧光的红色荧光。在AIA作用下，人口腔癌细胞系的SLAP和肿瘤中也观察到了红色荧光。与ALA相关的荧光物质被认为是原卟啉，这与人类癌症中引起的自体荧光是一致的。ALA对仓鼠和裸鼠肿瘤组织的红色荧光强度也有增强作用，ALA可用于口腔癌的荧光诊断，以增强早期或小型癌的自发荧光强度。虽然基于ALA的光动力疗法在不同的实验条件下被评价为裸鼠荣誉，但治疗后仅观察到肿瘤浅层坏死，结节状肿瘤没有任何消退。在ALA为基础的光动力学治疗结节癌组织的临床应用之前，还需要进一步的实验

This study was carried out to investigate application of 5-anunorevulinic acid (ALA) for diagnosis and treatment of oral cancer. The relationship between autofluorescence and AL.A induced fluorescence was analyzed biochemically, and effect of photodynamic therapy using AIA on nude mouse tumor was evaluated histologically. The autofluorescence arising in human oral cancer was reported to be associated with protoporphyrin, and similar poiphyrins were observed in oral cancers induced in hamsters and oral-cancer cell lines. After topical or systemic administration of ALA, red fluorescence which was similar to autofluorescence in human cancer was observed in oral mucosa and cancer induced in hamster. Red fluorescence was also observed in slap and tumor formed by human oral-cancer cell lines under administration of AIA. The fluorescent substance associated with ALA was suggested to be protoporphyrin, which was consistent with those caused autofluorescence in human cancer. The enhanced intensity of red fluorescence was also demonstrated in cancer tissues of hamster or nude mouse under administration of ALA, and ALA could be applied to fluorescence diagnosis for oral cancer to enhance intensity of autofluorescence in early-staged or small-sized cancer. Although ALA-based photodynamic therapy was evaluated in nude mouse honor under various experimental conditions, tumor necrosis was observed in only superficial area and nodular tumor did not show any regression after the therapy. Further experiments would be necessary before clinical application of ALA-based photodynamic therapy for nodular cancer tissue