Gene Therapy Protects Mice From Irradiation

Scientists have successfully protected mice against the harmful effects that radiation can have on bone marrow using gene therapy. Based on these findings, the researchers believe this approach may be able to protect first responders in the event of a radiologic accident or the detonation of a crude radiologic weapon, or "dirty bomb.”

The researchers, from the University of Pittsburgh School of Medicine (PA, USA), presented their findings at the American Society of Gene Therapy annual meeting in Baltimore (MD, USA) in May/June 2006.

Since the events of September 11, 2001, in New York City (NY, USA), there has been growing apprehension that terrorists may use a dirty bomb--a conventional explosive wrapped in radiologic material--or attack a nuclear power facility to disperse high-dose radiation across a populated area. Specialists believe a considerable number of the population would die within 30 days of exposure to a high dose of radiation from such an event, which has prompted the U.S. federal government to fund efforts to develop medical interventions against radiologic and nuclear threats.

In this study, researchers utilized gene therapy to deliver the compound manganese superoxide dismutase-plasmid liposome (MnSOD-PL) to the cells of female mice. Twenty-four hours later, groups of mice that received the treatment and control mice that did not were exposed to varying doses of whole body radiation. Following irradiation, the mice were weighed daily and observed for signs of irradiation-induced damage to their bone marrow.

Control mice irradiated at the higher doses lost weight and died rather quickly because of bone marrow damage. In contrast, mice treated with the MnSOD-PL gene therapy demonstrated no changes in body weight, had little bone-marrow damage, and lived longer compared to the control irradiated mice.

According to researcher Joel S. Greenberger, M.D., professor and chair of the department of radiation oncology and co-director of the Lung Cancer Center at the University of Pittsburgh Cancer Institute, the findings of this study have implications not only for first responders to a radiologic accident or attack but also to anyone else who might be exposed.

"This treatment is probably most effective when it is administered before exposure to radiation, as would be the case for first responders entering a radioactive environment. However, we have shown that it does have post-exposure, or mitigation, properties when we've administered it as a supplement to bone marrow transplantation. So, it also may be effective for treating people who have already been exposed to a radioactive event,” he said.

This work was supported by the U.S. National Institute of Allergy and Infectious Diseases (Bethesda, MD, USA) as part of its research program on Medical Countermeasures Against Radiological and Nuclear Threats.



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