Survival after total body irradiation: effects of irradiation of exteriorized small intestine

• Published in: Radiotherapy and oncology Vol. 23; no. 3; pp. 160 - 169
• Main Authors: Vriesendorp, H.M., Vigneulle, R.M., Kitto, G., Pelky, T., Taylor, P., Smith, J.
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier Ireland Ltd 01.03.1992
• Subjects: Abdominal irradiation; Animals; Crypt stem cell; Dose-Response Relationship, Radiation; Intestine, Small - radiation effects; Morphometric intestinal histology; Radiation Injuries, Experimental - mortality; Radiation Protection; Radiosensitivity small intestine; Rats; Rats, Inbred Strains; Specific Pathogen-Free Organisms; Whole-Body Irradiation - mortality; Morphometric intestinal histology; Abdominal irradiation; Crypt stem cell; Radiosensitivity small intestine
• ISSN: 0167-8140; 1879-0887
• DOI: 10.1016/0167-8140(92)90326-P

Rats receiving lethal irradiation to their exteriorized small intestine with pulsed 18 MVp bremsstrahlung radiation live about 4 days longer than rats receiving a dose of total-body irradiation (TBI) causing intestinal death. The LD 50 for intestinal irradiation is approximately 6 Gy higher than the LD 50 for intestinal death after TBI. Survival time after exteriorized intestinal irradiation can be decreased, by adding abdominal irradiation. Adding thoracic or pelvic irradiation does not alter survival time. Shielding of large intestine improves survival after irradiation of the rest of the abdomen while the small intestine is also shielded. The kinetics of histological changes in small intestinal tissues implicate the release of humoral factors after irradiation of the abdomen. Radiation injury develops faster in the first (proximal) 40 cm of the small intestine and is expressed predominantly as shortening in villus height. In the last (distal) 40 cm of the small intestine, the most pronounced radiation effect is a decrease in the number of crypts per millimeter. Irradiation (20 Gy) of the proximal small intestine causes 92% mortality (median survival 10 days). Irradiation (20 Gy) of the distal small intestine causes 27% mortality (median survival > 30 days). In addition to depletion of crypt stem cells in the small intestine, other issues (humoral factors, irradiated subsection of the small intestine and shielding of the large intestine) appear to influence radiation-induced intestinal mortality.