Related Experiment Videos
In vivo radiation protection by nitric oxide modulation
J Liebmann1, A M DeLuca, D Coffin
1Radiation Biology Branch, National Cancer Institute, Bethesda, Maryland 20892.
Cancer Research
|July 1, 1994
Summary
Nitric oxide (NO) modulates radiation toxicity. Inhibiting or releasing NO protected mice from radiation, suggesting blood flow alterations underlie changes in radiosensitivity.
Area of Science:
- Radiation biology
- Pharmacology
- Physiology
Background:
- Drugs affecting blood flow can protect against radiation.
- Nitric oxide (NO) plays a role in regulating physiological processes.
Purpose of the Study:
- To investigate the role of NO in modulating whole-body radiation toxicity.
- To determine if NO levels affect the radiosensitivity of normal tissues.
Main Methods:
- Utilized NG-nitro-L-arginine (a nitric oxide synthase inhibitor) and DEA/NO (a NO-releasing agent) in C3H mice.
- Administered agents prior to whole-body irradiation and assessed survival rates (LD50/30).
- Measured [14C]etanidazole binding to bone marrow to assess hypoxia.
Main Results:
- NG-Nitro-L-arginine significantly increased the radiation LD50/30, indicating protection.
- DEA/NO treatment also significantly reduced radiation toxicity, increasing the LD50/30.
- Both agents exacerbated bone marrow hypoxia, suggesting a link between hypoxia and radiosensitivity.
Conclusions:
- Perturbations in NO levels profoundly affect in vivo radiosensitivity of normal tissues.
- Alterations in regional blood flow are hypothesized to underlie the observed changes in radiosensitivity.
- NO modulation represents a potential strategy for mitigating radiation toxicity.