Washington, Nov 8: A new research on a mouse model has boffins hopeful that antioxidant-based pain killers will, in the future, become a viable alternative to addictive medications such as morphine.

The research, which examines the effects of antioxidants as pain killers, was conducted by a team of boffins from Ohio State and Ataturk University in Erzurum, Turkey, led by Robert Stephens, a professor of physiology and cell biology at Ohio State University and lead author of the study.

The team found that synthetic antioxidants practically eradicated pain-like behaviour in nearly three-quarters of mice with inflamed hind paws.

Robert Stephens said that currently there was a limited choice of painkillers in the market, and that people suffering from chronic pain faced the danger of becoming addicted to the drugs.

The research on antioxidants based painkillers, he said, was conducted to find out whether or not they were a viable choice to addictive medications.

“When it comes to pain killers, there aren't many choices between over-the-counter pain relievers like ibuprofen and aspirin and prescription opiates like morphine. We need drugs that fall somewhere between these two extremes,” Stephens said.

“Someone suffering from chronic pain can become dependent on, or even addicted to, heavy-duty pain killers like morphine,” he said.

As a part of the study, the research first injected one of three different synthetic antioxidants into mice. An additional group of control mice received only saline.

Shortly after the antioxidant or saline injections, the researchers injected formalin, an irritant that causes inflammation this provoking pain-like behaviour, into the left hind paw of each mouse.

Researchers then spent the next 30 minutes studying how much time an animal spent licking and biting its injured paw. This kind of behaviour suggests that the animal is in pain or discomfort.

The researchers divided the 30-minute observation session into three distinct periods – a five-minute acute phase, when the body first senses and reacts to pain, followed by a 5- to 15-minute period of relative stillness, as the body uses its own mechanisms to try to inhibit the pain, and ending with a 15- to 30-minute period called the tonic phase, during which a mouse starts to again vigorously lick or bite its irritated paw, suggesting that it still feels pain or discomfort.

The team found that three antioxidants significantly reduced the amount of time that mice spent biting and licking their injured paw during both the acute and tonic phases, and that there was a 70- to 90-percent reduction in pain-related behaviours during the acute phase, and a 78- to 98-percent reduction in such behaviour during the tonic phase.

Stephens said that the results had surprised the researchers, and now had them hopeful that antioxidants are viable pain killers.

“We were surprised to see such a major decrease in pain in the mice, particularly during the acute phase. The antioxidants seem to preempt pain-like behaviour,” Stephens said.

The study appears in a recent issue of the journal Behavioural Brain Research. (ANI)