Interleukin 1 increases thymidine labeling index of normal tissues of mic but not the tumor
- Stanford Univ. School of Medicine, Stanford, CA (United States)
This study was conducted to investigate the action of human recombinant interleukin 1 as a radioprotector for different mouse normal cells other than bone marrow cells. Semi-continuous injections of tritiated thymidine were administered every 6 h, over 24 h to determine thymidine labeling index. Mice were injected with recombinant human interleukin 1 24 h prior to tritiated thymidine and were compared to control animals that did not receive interleukin 1. Mice were killed 1 h after the last thymidine injection. The 24 h thymidine labeling index for normal tissues and RIF-1 tumor was determined. Labeling indices were also determined 1-14 days after a series of fractionated irradiations with or without pretreatment with a single dose of interleukin 1 administered 24 h prior to the first radiation. The thymidine labeling index of normal tissues was higher following the injection of recombinant human interleukin 1 24 h before radiolabeling. This was found in all normal tissues tested. The thymidine labeling index of RIF-1 fibrosarcoma was not affected by interleukin 1 injection. A single interleukin 1 injection 24 h before the first radiation fraction also increased the thymidine labeling indices of normal tissues after localized fractionated irradiation. The thymidine labeling index of RIF-1 tumor was not increased by interleukin 1 administration except after relatively high radiation doses (20 Gy in five fractions). The ability of interleukin 1 to enhance the thymidine labeling index declined after the first day following the completion of fractionated irradiation. Recombinant human interleukin 1 increased the 24 h thymidine labeling index in normal tissues in mice, but not in RIF-1 tumor. Fractionated irradiation could maintain the effect of a single dose of interleukin 1, administered 24 h prior to the first fraction, up to 24 h after the end of radiation. 25 refs., 3 figs., 1 tab.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 86490
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 29, Issue 4; Other Information: PBD: 1 Jul 1994
- Country of Publication:
- United States
- Language:
- English
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