Unterschiedliche Effekte der Bestrahlung im gesunden Pankreas und im Pankreaskarzinom der Ratte

Abstract

Purpose: Radiation was suggested for the vascular targeted therapy of malignant tumors. In this study, we compared the radiogenic effects on microcirculation in healthy and malignant pancreatic tissue. Material and Methods: The model of duct-like pancreatic cancer (DSL6A) was used. The tumors were locally irradiated with 15Gy 4 weeks after intraperitoneal inoculation. Additionally, local radiation of normal pancreas was performed in healthy animals. Intravital microscopy of tumor and normal pancreatic microvessels was performed 5 days after radiation. Relevant parameters were erythrocyte velocity and functional vessel density. Tumor apoptosis and fraction of vital tumor cells were quantified histologically 5 and 12 days after radiation. Results: The local radiation with 15Gy caused a pronounced impairment of blood flow (p = 0.006) and functional capillary density (p = 0.001) in the normal pancreas 5 days after radiation while the tumor blood flow was not significantly changed. A significant reduction of fraction of the vital tumor cells (p = 0.010) and a significant increase of tumor apoptosis (p = 0.017) were observed 12 days after radiation. Conclusion: Local radiation reduces the blood flow in healthy pancreas, but not in pancreatic tumor. Tumor cell death is the leading characteristic of radiation-injury in malignant pancreatic tissue. The present study showed that radiation is not an universal approach for vascular-targeted therapy in malignant pancreatic tissue.