Circadian rhythm affects wound healing, daytime injuries heal faster

Written by Freya Leask

Research led by the Medical Research Council has demonstrated the injuries sustained during the day heal approximately 60% faster.

A new study, published in Science Translational Medicine, is the first to demonstrate a relationship between wound healing and the time of day the wound was sustained. This discovery could have implications for scheduling of surgical procedures and development of therapeutics to enhance wound healing. The study was led by the Medical Research Council (MRC) Laboratory of Molecular Biology (Cambridge, UK).

Dr John O’Neill, senior author, MRC Laboratory of Molecular Biology, explained: “This is the first time that the circadian clock within individual skin cells has been shown to determine how effectively they respond to injuries. We consistently see about a 2-fold difference in wound healing speed between the body clock’s day and night. It may be that our bodies have evolved to heal fastest during the day when injuries are more likely to occur.”

In tests on fibroblasts, keratinocytes and mice demonstrates that during the ‘daytime’, skin wounds healed almost twice as fast as wounds incurred during the night. Analysis of records from 118 patients from major burns units in England and Wales found that this effect was mirrored in burns injuries.

During the day, skin cells were found to move to the site of the wound to repair it, driven by increased protein activity, particular the protein actin, which provides scaffolding and movement within a cell. There was also more collagen deposited at the wound site during the day. This continued for up to two weeks after the incidence of the wound.

Dr John Blaikley, study author and clinician scientist, University of Manchester (UK), who contributed to the analysis of burns patients, commented: “Treatment of wounds costs the NHS around £5 billion a year, which is partly due to a lack of effective therapies targeting wound closure. This research, for the first time, shows how circadian factors are important for wound healing. By taking these into account, not only could novel drug targets be identified, but also the effectiveness of established therapies might be increased through changing what time of day they are given.”

Source: MRC press release