CURWOOD: It’s Living on Earth, I’m Steve Curwood. In a minute, we’ll meet a physician whose innovative prescriptions bypass the drug companies. But first this note on Emerging Science from Matt Hoisch.

HOISCH: Photosynthesis isn’t the first thing that comes to mind when you think about heart attacks. But it’s exactly what a team of researchers at Stanford and the University of Pennsylvania thought of. The team knew that photosynthesis, the process in plants that generates sugars, also yields oxygen as a by-product. So maybe, the researchers hypothesized, it could help people recover from heart attacks caused by a blocked artery or blood clot that deprived the heart of oxygen.

To test the hypothesis, the team cut off oxygen to rat hearts to simulate a heart attack. They then injected photosynthetic cyanobacteria into some of the oxygen-starved hearts and found that in these rats, oxygen levels tripled. But to work successfully, photosynthesis needs sunlight. So the team exposed some of the hearts to light to see what would happen. In the light-treated rats, oxygen levels shot up to 25 times the levels observed just after the heart attacks. And photosynthesis also helped in recovery. Four weeks after the treatment, the rats that had received the photosynthetic bacteria showed less heart damage than untreated rats.