5-ALA/PpIX photodiagnosis of stress-induced gastrointestinal metastatic tumours in laboratorial animals

Combined spectroscopic and biochemical measurements were used to improve diagnostic accuracy and to evaluate gastrointestinal tract (GIT) neoplasia development parameters noninvasively. Experiments were performed in mongrel male rats divided into 2 groups - control and experimental. To induce gastric cancer, the rats underwent to chronic stress (overpopulation during 9 months) and diet including the daily using of mtoluidine (25 mu g/kg weight) in food and water with a solution of sodium nitrite (0.2%) for 9 months. We studied effectiveness of 5-ALA/PpIX fluorescent analysis of gastric carcinoma and biochemical stress-corresponding indices detection for early diagnosis of primary gastric tumours and their metastatic spreading in liver. Affected by precancerous and cancerous alterations mucosa reveal red fluorescence, related to the accumulation of 5-ALA/PpIX. Liver tissues investigated also presented increase of the red fluorescence, which was used as an indicator for possible pathologic process detection there. The histological examination revealed liver metastases in 67.8 % of the rats with gastric cancer. Biochemical indicators detected malignant alterations presence in GIT, and fluorescent observation addressed the exact area and borders of neoplastic lesions. 5-ALA/PpIX fluorescence detection allow to find and precisely map premalignant and malignant areas of gastric mucosa and liver metastases of stress-induced gastric heterogeneous adenocarcinoma and biochemical evaluation of stressrelated compounds increased the efficiency of such diagnosis and reveal information about the dynamics of lesions development. Diagnostic accuracy achieved using fluorescent detection reaches 93% for gastric carcinoma, and 87% for pre-cancerous mucosa alterations observed.