Study finds sex differences in the healing process after a muscle injury

The time period in which muscles heal after injury may depend on biological sex, and applying personalized treatment may help optimize recovery, according to a new study. Researchers from Duquesne University in Pittsburgh will present their work this week at the American Physiology Summit, the flagship annual meeting of the American Physiological Society (APS), in Long Beach, California. 

Muscle regeneration is a normal part of the healing process after sustaining a muscle injury. A variety of factors can affect how quickly muscles heal, including age, exercise and biological sex.

"Males and females, both athletic and nonathletic, differ in the healing process, such as the time course of inflammation, recovery of muscle force and period of [muscle] regeneration," said Siyu Liu, MS, lead author of the study. The cause for variations in healing times are not well understood.

Liu's research team looked at a mouse model of muscle injury in which the muscle progressively loses mass and weakens. The research team performed muscle physiology testing to examine muscle repair and regeneration on days three and 12 post-injury. The female mice showed greater improvement on muscle function between the two testing dates than the males. This variation in the healing process could be due to estrogen levels, but uncovering the relationship of hormones to muscle recovery requires additional study.

Muscle regeneration continued to progress in both sexes after day 12, indicating that treatment could still be beneficial even two weeks after injury. Because the females healed more quickly, Liu suggested that males may benefit from beginning a treatment regimen that includes exercise at an earlier point than females when faced with muscle injuries.

By understanding the difference between males and females in the healing process, medical professionals can give personalized treatment plans, including exercise and medical treatment, based on time course."

Siyu Liu, MS, lead author of the study