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Muscle Repair in Horses Declines with AgeBy Kentucky Equine Research Staff · October 16, 2017

If you’ve ever owned a horse with an injury, waiting for a full recovery and the vet’s green light to get back in the saddle can be an excruciating process. On a microscopic level, however, skeletal muscle repair following injury is actually a well-orchestrated process. If you’re young, that is.

“Skeletal muscle recovery is a highly coordinated process involving cross-talk between immune and muscle cells. It is well known that the physiological activities of both immune cells and muscle stem cells decline with age, thereby blunting the capacity of skeletal muscle to regenerate,” explained Carla Domingues-Faria, Ph.D., in a recent study*.

When skeletal muscle is injured, there are four key steps in the repair process:

  1. Necrosis: death of the damaged muscle cells;

  2. Inflammation: immune cells break down the injured muscle tissue and remove cellular debris;

  3. Activation and differentiation of satellite cells: immune cells send out signals to attract muscle precursor cells called “satellite cells” to the injury site; and,

  4. Maturation: newly formed muscle fibers mature and remodel the muscle.

With age, the functions of both the satellite cells and immune cells that play vital roles during the repair process are diminished. As a result, the muscle and immune cells are less capable of the cross-talk required for repair, thereby slowing muscle regeneration.

“Diet is known to impact the capacity of muscle to regenerate. Research shows that omega-3 fatty acids possess potent anti-inflammatory effects and can potentially improve the cross-talk between cells during skeletal muscle repair,” explained Kathleen Crandell, Ph.D., a Kentucky Equine Research (KER) nutritionist. “KER developed an omega-3 product called EO•3, a marine-derived, palatable oil that is top-dressed onto the feed. It contains both EPA and DHA.”

In addition to omega-3s, polyphenols (found in yeast fermentates and green tea extracts) and vitamin D also appear to be beneficial during skeletal muscle repair in older horses.

The potential for diet to stunt the aging process and support skeletal muscle repair is exciting. It is important to appreciate, however, that obesity is associated with a decrease in muscle repair no matter what supplement you offer.

*Domingues-Faria, C., M-P., Vasson, N. Goncalves-Mendes, et al. 2016. Skeletal muscle regeneration and impact of aging and nutrition. Ageing Research Reviews. 26:22-36.