Hindlimb Muscle Atrophy Occurs From Peripheral Nerve Damage in a Rat Neuropathic Pain Model

Abstract

Hindlimb muscle atrophy occurs in both ipsilateral and contralateral sides following induction of neuropathic pain by unilateral peripheral nerve damage. Muscle changes of the ipsilateral side are more pronounced than those of the contralateral side.

Characterizing Activity and Muscle Atrophy Changes in Rats With Neuropathic Pain

“…The rate and amount of weight the rats gained aligns with weight gain expectations provided by the breeder (Charles River). Our results contradict those of Choe et al (2011), who found that body weight in rats with neuropathic pain was less than that of control and sham groups over 14 days, including baseline. However, the spinal nerve ligation (SNL) model that Choe et al used to induce neuropathic pain is more invasive than the CCI model we used, which may explain this difference between studies.…”

“…We also observed limping, guarding, and altered gait in these CCI rats, which likely reflected changes in overall animal activity/movement (Bennett & Xie, 1988; Jaggi et al, 2009). Our findings support those of Choe et al (2011), who found that rats with neuropathic pain had lower activity levels than controls, but contradict those of Bennett and Xie (1988), who found no decrease in general activity in the rats with neuropathic pain. The latter authors, however, described activity changes but did not quantify spontaneous activity, as we did.…”

“…Finally, decreased nutritional intake can also contribute to muscle atrophy. In a previous study, rats with neuropathic pain following SNL had significant decreases in total dietary intake 15 days after surgery (Choe et al, 2011), which may have contributed to the outcome of muscle atrophy. One limitation of the present study was that, while we did measure body weight daily, we did not record nutritional intake.…”

“…Bennett and Xie (1988) described skeletal muscle atrophy 58 days after CCI, while in the present study we observed it occurring as early as 2 weeks following CCI. Other researchers have reported atrophy of the SOL (Choe et al, 2011) and gastrocnemius and rectus femoris muscles (Daemen et al, 1998) following spinal and peripheral nerve injury, respectively. In a study on sciatic nerve crush injury in rats, Beehler et al (2006) found that the SOL and EDL muscles exhibited a degree of atrophy similar to what we found in the present study.…”

“…Hutchinson, Linderman, and Basso (2001) found that muscle atrophy is present in animals with induced spinal cord injury. Others have demonstrated muscle atrophy in various preclinical models of neuropathic pain (Bennett & Xie, 1988; Choe, Kim, An, Lee, & Heitkemper, 2011; Daemen et al, 1998). However, the relative contributions of nerve injury and decreased activity on muscle atrophy remain uncertain.…”