Broccoli Chemical Saves Mice from Radiation Death
Your mother (or perhaps your spouse) always reminds you to eat your broccoli. Indeed, it is quite good for you. Not only is it packed full of vitamins, but it also contains cancer-fighting compounds, such as I3C. Our bodies metabolize this molecule into 3,3'-diindolylmethane (DIM), which also wages a war on cancer.
Now, a team of researchers led by Eliot Rosen has shown that administering DIM to mice exposed to a lethal dose of gamma radiation can rescue a substantial proportion of them. (See figure.)
The survival curve shows that the researchers zapped mice (20 in each group) with a dose of gamma radiation large enough to kill all the control animals (black line) within 10 days. For the experimental groups, they administered a regimen of DIM every day for 14 days. How quickly they administered the first dose made a big difference: At least 50% of mice that were given DIM within 10 minutes (red line) or 2 hours (purple line) survived for 30 days. Survival fell to 40% for mice given their first dose after 4 hours (blue line) and to merely 30% if the first dose was administered after 24 hours.
The authors conducted several more experiments aimed at determining how DIM works. Based on their findings, they concluded that DIM induces a DNA repair response and blocks cell death.
Of course, the major shortcoming of this work is that it was performed in mice, not humans. Unfortunately, clinical trials are unlikely since most humans won't voluntarily submit themselves to a lethal dose of gamma radiation.
Finally, it may sound like a 30% to 50% survival rate is quite low, but this is better than nothing, which is basically our current course of action. Most treatment for acute radiation poisoning consists of "supportive care," which means making the patient feel comfortable while a nurse calls the funeral home.
Therefore, DIM may give acute radiation patients a fighting chance. Perhaps nuclear power plants and other facilities should consider stocking up.
Source: Saijun Fan et al. "DIM (3,3'-diindolylmethane) confers protection against ionizing radiation by a unique mechanism." PNAS. Published online before print: 14-Oct-2013. DOI: 10.1073/pnas.1308206110