New anti-radiation drug works days after exposure

A new drug that protects mice days after exposure to radiation may one day treat side effects of cancer therapy or protect astronauts from harmful cosmic rays, scientists say.
Gabor Tigyi from the University of Tennessee Health Science Centre and colleagues spent 10 years exploring the power of lysophosphatidic acid (LPA), a naturally occurring signalling molecule that seems to give cells a better chance against radiation exposure.
LPA can buy the cell more time to repair its DNA through a mechanism that remains unclear, said Tigyi.
Previously, researchers developed a drug that interacts with LPA receptors on cells to reduce the effects of radiation sickness in bone marrow and in the digestive system - two of the areas most commonly affected by radiation exposure.

However, the drug was not potent enough to be medically useful.
Now they have used a computer model to subtly tweak the drug's molecular structure and create DBIBB, a new drug that should be much more potent, 'New Scientist' reported.

Tigyi and his colleagues started off exploring whether DBIBB could help mice exposed to radiation doses of 15.7 grays.
Without treatment, 12 of 14 mice died two weeks after exposure. But after prompt treatment with DBIBB, beginning 26 hours after exposure, 13 of 14 mice were still alive two weeks later.
Researchers then ran tests to see what would happen if they did not give mice DBIBB until 72 hours after exposure to 8.5 grays.

One month later, 12 of 15 untreated mice had died - but 14 of the 15 mice that received delayed DBIBB therapy were still alive.
Tigyi hopes the drug would be more commonly used to treat side effects of radiation in cancer therapy or to protect astronauts on their journey to Mars and beyond.