Putting ice on injuries could slow healing
Slapping a packet of frozen peas on a black eye or a sprained ankle may prevent it getting better, new research suggests.
For years, people have been told to freeze torn, bruised or sprained muscles to reduce the swelling.
But now for the first time, researchers have found that it could slow down the healing as it prevents the release of a key repair hormone.
This discovery turns the conventional wisdom that swelling must be controlled in order to encourage healing and prevent pain.
It could also lead to new therapies for acute muscle injuries that lead to inflammation.
The study, published in the Federation of American Societies for Experimental Biology journal, suggests muscle inflammation after acute injury is essential to repair.
Professor Lan Zhou and colleagues at the Neuroinflammation Research Centre at the Cleveland Clinic in Ohio discovered inflamed cells produce a high level of a hormone called insulin-like growth factor-1 (IGF-1) which significantly increases the rate of muscle regeneration.
During the study, scientists studied two groups of mice. The first group was genetically altered so they could not form an inflammatory response to injury.
The second group was normal.
All mice were then injected with barium chloride to cause muscle injury.
The first group of mice did not heal, but the bodies of the second group repaired the injury.
When they studied the muscle tissue they saw the healthy mice produced a high level of IGF-1 in their inflamed tissue.
Prof Zhou, said: "We hope that our findings stimulate further research to dissect different roles played by tissue inflammation in clinical settings, so we can utilise the positive effects and control the negative effects of tissue inflammation."
This discovery could change how much patient monitoring is required when potent anti-inflammatory drugs are prescribed over a long period.
Gerald Weissmann, editor of the Federation of American Societies for Experimental Biology journal, said: "For wounds to heal we need controlled inflammation, not too much, and not too little.
"It's been known for a long time that excess anti-inflammatory medication, such as cortisone, slows wound healing.
"This study goes a long way to telling us why – insulin-like growth factor and other materials released by inflammatory cells helps wound to heal."