CO May Cut Skeletal Muscle Injuries

Carbon monoxide may be known for long term health hazards, but a new study has revealed that inhaling it can significantly reduce skeletal muscle injury following limb peripheral vascular disease (ischemia).

Ischemia is a condition where blood flow is interrupted and can be compounded by reperfusion, when damage is caused after the blood supply returns to the tissue. When this occurs, there can be limb loss or death.

A team from Massachusetts General Hospital in Boston reviewed the results the experiments conducted on 23 mice from two groups, in which 10 were given CO and 13 were not,

“Mice that inhaled a low dose CO after an onset of ischemia resulted in decreased markers of inflammation locally in the injured skeletal muscle and systemically in the blood, and had increased energy levels after ischemia/reperfusion (I/R) mediated injury within the injured limb," said Dr Rajendra Patel, clinical and research fellow in the department of vascular surgery.

“All of these factors may allow for a faster and more complete recovery in humans, and even decrease limb loss or death," he added.

For the study, scientists created a unilateral hind limb I/R using an orthodontic rubber band. It was then applied to 23 mouse limbs for 1.5 hours.

Immediately after application of the band, during ischemia and the initial six hours of reperfusion, 10 mice were put in sealed chambers equilibrated with gases composed of 250 ppm CO mixed with room air. The 13 other mice were put in a chamber of air alone.

The mice were all mice were placed in room air at ambient temperature after six hours reperfusion and sacrificed after 24 hours

The findings revealed that CO treated mice had less skeletal muscle injury compared to room air treated mice (a mean 16.8 percent vs. 29.2 percent).

This group also had higher tissue ATP levels when compared to the control group (mean 21.9 vs. 8.0 contralateral) and serum and muscle KC levels were markedly reduced in the CO group when compared to the control group.

There was no difference in mean blood pressure and heart rate in both groups of mice when measured at baseline, 6 and 24 hours reperfusion.

“Although CO is known to be a toxic and deadly gas at high concentrations, our findings support the role of low CO treatment in acute limb threatening ischemia, and our research may help patients in the future," said Dr. Patel.

The study was presented during the Vascular Annual Meeting, June 5-8, San Diego, California