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

本研究旨在探讨5-环己酸（ALA）在口腔癌诊断和治疗中的应用。生化分析了自身荧光与AL.A诱导荧光的关系，组织学评价了AIA光动力治疗裸鼠肿瘤的效果。据报道，人类口腔癌中产生的自身荧光与原卟啉有关，在仓鼠和口腔癌细胞系诱导的口腔癌中也观察到类似的卟啉。局部或全身给药后，在口腔黏膜和仓鼠诱导的癌症中观察到类似于人类肿瘤自身荧光的红色荧光。在AIA作用下，人口腔癌细胞系的巴掌和肿瘤也可见到红色荧光。与ALA相关的荧光物质可能是原卟啉，这与人类癌症中引起自身荧光的物质一致。在给ALA的仓鼠和裸鼠癌组织中，红色荧光强度也增强，ALA可用于口腔癌的荧光诊断，在早期或小肿瘤中增强自身荧光强度。尽管在各种实验条件下对裸鼠荣誉进行了基于ala的光动力治疗，但仅在浅表区域观察到肿瘤坏死，治疗后结节性肿瘤未出现任何消退。基于ala的光动力治疗结节性癌组织的临床应用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