CXCL 10 increases in human skeletal muscle following damage but is not necessary for muscle regeneration

CXCL 10 is a chemokine for activated and memory T cells with many important immunological functions. We recently found that CXCL 10 is upregulated in human muscle following contraction‐induced damage. No information is available on the role of CXCL 10 in the context of muscle damage or repair. In this study, we confirm that CXCL 10 is elevated in human muscle at 2 and 3 days following damage and perform cell culture and animal studies to examine the role of CXCL 10 in muscle repair. CXCL 10 did not impact proliferation rates of human primary myoblasts but it did promote myogenic differentiation in vitro, suggesting a possible direct impact on muscle regeneration. To test if CXCL 10 was dispensable for effective muscle regeneration in vivo , we measured functional and histological markers of muscle repair out to 14 days postmuscle injury caused by a myotoxin in wild‐type ( WT ) mice and CXCL 10 knockout ( KO ) mice. Between genotypes, no significant differences were found in loss or restoration of in situ muscle force, cross‐sectional area of newly formed myofibers, or the number of embryonic myosin heavy chain‐positive myofibers. In addition, KO animals were not deficient in T‐cell accumulation in the damaged muscle following injury. Gene expression of the other two ligands ( CXCL 9 and 11) that bind to the same receptor as CXCL 10 were also elevated in the damaged muscle of KO mice. Thus, other ligands may have compensated for the lack of CXCL 10 in the KO mice. We conclude that CXCL 10 is not necessary for effective muscle regeneration.