Influence of Local Temporary Ischemia on Radiotherapy Effects

Here we summarize and discuss the body of information concerning mechanisms and regulation of local short-duration preconditioning that may accompany experimental radiation therapy. Based on the results of our previous studies in vivo we investigated possible impact of local temporary ischemia on the effectiveness of ionizing radiation-based anti-cancer therapy. We used total body-irradiated or abdomen only-irradiated healthy rats. Chosen blood parameters, changes in bone marrow cytological picture as well as histological picture of the small intestine were used as toxicity markers. We found a significant transient modification in lipid peroxides, triglycerides, uric acid concentration, SOD isoenzymes activity in the rat serum, increased numbers of small intestine crypts and suppression of bone marrow polychromatic erythrocytes and polychromatic erythrocytes with micronuclei. No significant differences were observed in MnSOD isoenzyme activity in serum and in small intestine homogenates after local temporary ischemia, nor after irradiation, nor combined treatment. Some differences were observed in intestinal tissue CuZnSOD activities. Nevertheless, great variations in response to ischemia, radiation or combined treatment was noted concerning this parameter. Histological picture of the small intestine from ionizing radiation-treated rats has indicated a marked protection of crypt survival by local temporary ischemic preconditioning. Some of the ionizing radiation-caused toxic effects were reduced in animals treated with local ischemic preconditioning. Together, these results provide a new insight into development of a more effective anticancer therapy combining short-duration ischemia and ionizing radiation modality.