Detection of stress-induced gastrointestinal lesions using Al-phythalocynanines in experimental animals

Abstract

In our study aluminium–phthalocyanine (AlPc) compounds were applied for exogenous fluorescent diagnostics of adenocarcinoma of stomach in laboratorial animals (male adult rats (n=50)) after application of an experimental model of adenocarcinoma formation with metastasis. The neoplastic lesions were developed under the influence of social stress, as well as chemical stress using nitrosamines during 9 months period of application. Significant fluorescence signal in the region of 670-700 nm was observed in the neoplastic lesions, which absent in the normal mucosa investigated, related to the fluorescence of accumulated in the tumour area phthalocyanines. Autofluorescence background covered region at 450-650 nm with a maximum of 480-520 nm and consists mainly of protein cross-links and co-enzymes - NADH and flavin signals. Endogenous porphyrins fluorescence was also observed in the lesions with a maximum at 630-640 nm. Other organs (liver, small bowel, lungs) were also investigated for a presence of metastases. Histology examination of the lesions was used as a “gold standard” for comparison of the spectral data. Visually, a presence of accumulation sites of AlPc in a form of bright pink patches after excitation at 405 nm was observed, vs. healthy tissue, which remained blue-violet due to autofluorescence signal. Thus allow to use the AlPc fluorescence discrimination not only in spectroscopic mode of detection, but for imaging of the lesions investigated, which is more preferable in the case of clinical applications during endoscopic observations in humans.