Autofluorescence Endoscopy Diagnosis Of Early Colorectal Carcinoma - The Original Blood Porphyrin Ix, The Organization Of Protoporphyrin ¢ù Content, And Colorectal Cancer In Vivo Autofluorescence Differences

Objective: to investigate the mechanism of laser induced autofluorescence in vivo of rat colorectal carcinoma by studying blood protoporphyrin IX and tissue protoporphyrin IX.Methods: 70 Sprague-Dawley rats were divided into two groups: test group (60) and control group (10). In test group , DMH (25 mg per kg) was injected into rat abdominal cavity once a week for 18 weeks. In control group, rats were not treated by DMH. At 20th week , laser induced autofluorescence in vivo excited at 370nm was collected in test group. Blood protoporphyrin IX in two groups and tissue protoporphyrin IX in test group were examined by fluorospectrophotometer.Results: different stage tissues showed peaks at 460nm.73% of advanced colorectal carcinoma and 69% of early-stage colorectal carcinoma showed a peak at 635nm. I635/I460 of early stage colorectal carcinoma and advanced colorectal carcinoma was higher than that of normal tissue (P<0.05). There was no significant difference between I635/I460 of early stage colorectal carcinoma and that of advanced colorectal carcinoma (P>0.05). Protoporphyrin IX in normal tissue, early stage colorectal carcinoma and advanced colorectal carcinoma was 317.099 ?6.859ng/g?416.814?.786ng/g and 606.874?1.798ng/g respectively. The protoporphyrin IX of advanced colorectal carcinoma was larger than that of normal tissue, early stage colorectal carcinoma (P<0.001).The protoporphyrin IX of early stage colorectal carcinoma was larger than that of normal tissue (P<0.001). Blood protoporphyrin IX in test group and control group was 2.224?.323ug/ml?1.663 ?0.092ug/mlrespectively. Blood protoporphyrin IX in test group was larger than that in control group (P<0.001). Blood protoporphyrin IX/Hb in test group and control group was 25.908 ?12.54ug/g and 10.609 ?0.929ug/g respectively. Blood protoporphyrin IX/Hb in test group was larger than that in control group(P<0.05). Conclusions:1) Laser induced autofluorescence of normal rat colorectal tissue and rat different-stage colorectal carcinoma in vivo at 635 nm is different. Difference of laser induced autofluorescence in vivo at 635nm may be caused by tissue protoporphyrin IX and blood protoporphyrin IX2) Blood protoporphyrin IX may be a factor to screen colorectal carcinoma.