Study shows lack of sleep slows wound healing: mice with obesity and type 2 have significantly slower healing of wounds compared to those with undisturbed sleep.
A new study has revealed that a good night’s sleep may be even more important to overall health than ever, especially for patients with type 2 diabetes. In a study out of the University of Tennessee, investigators looked at mice with obesity and type 2 diabetes, and sought to find a correlation between impaired sleep and wound healing.
This study comes after much is already known about compromised wound healing in patients with type 2 diabetes. As blood glucose levels remain elevated, arteries stiffen and blood vessels narrow, leading to decreased blood flow to wounds and, consequently, impaired healing. Additionally, diabetic neuropathy also plays a large and commonly known role in both development and progression of severe wounds. When glucose levels remain uncontrolled, nerve damage can occur and wounds can both develop and worsen without the knowledge of the patient. While both of these scenarios are well known and commonly studied, few studies have assessed fragmented and impaired sleep as a contributor to delayed wound healing in patients with diabetes.
Investigators of the study postulated that while patients with obesity who have type 2 diabetes are already at increased risk for surgical site infections, many patients with diabetes also experience sleep disturbance, which could further increase this risk.
What do we already know about impaired sleep in relation to wound healing? Adequate sleep is a driving force for proper immune function, and deprivation has been linked to immune system impairment and slower recovery. Cytokines production has been known to decrease under cases of fragmented and inadequate sleep, thus rendering a person unable to fight infections and decrease inflammation in an injured area.
In the present study, a total of 34 adult male mice were analyzed. Half of the mice were enrolled as having obesity and type 2 diabetes, and the other half were considered wild type with no ailments. Both groups of mice were studied under two separate treatment conditions — fragmented sleep and non-fragmented sleep. In the fragmented sleep phase, a bar was moved across the cage floor periodically for 12 hours per day to awaken the mice at frequent intervals. During the non-fragmented sleep phase, mice were undisturbed throughout the day.
Four days after the onset of the sleep fragmentation or non-fragmentation stage, each mouse was given a bilateral wound under full anesthesia. The wounds were closely assessed throughout the study with digital imagery to analyze surface area and progression or healing. Throughout the study, body weights and blood glucose levels were also measured and recorded.
Two-way ANOVA analysis was used to assess each mouse for wound size as a function of sleep fragmentation after 23 days, with p<0.05 considered statistically significant.
Percentage of wound closure was calculated for each mouse. Results from the two-way ANOVA revealed that 16 days following the skin biopsy, wound closure was significantly slower in mice who experienced fragmented sleep (p<0.0001) than those who remained undisturbed. Additionally, sleep fragmentation in the group with obesity and type 2 diabetes showed a significant delay in the time it took to reach 50% wound closure compared with the wild type mice who experienced the same sleep fragmentation.
While the results of the study may be limited to mice at present time, it brings about compelling evidence showing the implications impaired sleep has on wound healing in patients with type 2 diabetes. Wound management continues to plague the community with diabetes as clinicians continue to see more and more patients with diabetes-related injuries. With future studies focusing their attention on sleep as a potential cause for delayed wound healing, we may begin to see a shift in focus regarding diabetes management and prevention of injuries.
- In mice with obesity and type 2 diabetes, impaired sleep significantly delayed wound healing compared to those with undisturbed sleep.
- Mice with obesity and type 2 diabetes showed significantly slower wound healing compared to mice without diabetes.
- Future studies must address sleep deprivation and fragmentation in human patients with type 2 diabetes in order to assess sleep as a contributing factor to diabetic wound healing impairment.
Mclain, J. M., Alami, W. H., Glovak, Z. T., Cooley, C. R., Burke, S. J., Collier, J. J., Lydic, R. (2018). Sleep Fragmentation Delays Wound Healing in a Mouse Model of Type 2 Diabetes. Sleep. doi:10.1093/sleep/zsy156
How Diabetes Affects Wound Healing. (2018). Retrieved from https://www.woundcarecenters.org/article/living-with-wounds/how-diabetes-affects-wound-healing
Can lack of sleep make you sick? (2015, June 09). Retrieved from https://www.mayoclinic.org/diseases-conditions/insomnia/expert-answers/lack-of-sleep/faq-20057757