The superior healing capacity of MRL tendons is minimally influenced by the systemic environment of the MRL mouse

• Published in: Scientific reports Vol. 13; no. 1; pp. 17242 - 13
• Main Authors: Frankewycz, Borys, Bell, Rebecca, Chatterjee, Monideepa, Andarawis-Puri, Nelly
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 11.10.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 631/1647/767/1424; 631/1647/767/2200; 692/4023/1671/1835; 692/699/578; Allografts; Animals; Autografts; Humanities and Social Sciences; Inflammation; Knee Joint; Mice; multidisciplinary; Patellar Ligament; Science; Science (multidisciplinary); Tendons; Transplantation; Transplantation, Homologous; Wound Healing
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-023-42449-8

Murphy Roths Large mice (MRL) exhibit improved tendon healing and are often described as a “super-healer” strain. The underlying mechanisms that drive the superior healing response of MRL remain a controversial subject. We utilized a tendon transplantation model between MRL and “normal-healer” B6-mice to differentiate between the contribution of MRL’s innate tendon and systemic environment to its improved healing capacity. Patellar tendons with a midsubstance punch injury were transplanted back into the same animal (autograft) or into an animal of the other strain (allograft). Findings at 4 weeks showed that the innate MRL tendon environment drives its improved healing capacity as demonstrated by improved stiffness and maximum load in MRL-grafts-in-B6-host-allografts compared to B6-autografts, and higher modulus in MRL-autografts compared to B6-graft-in-MRL-host-allografts. Groups with an MRL component showed an increase in pro-inflammatory cytokines in the 3 days after injury, suggesting an early enhanced inflammatory profile in MRL that ultimately resolves. A preserved range of motion of the knee joint in all MRL animals suggests a systemic “shielding effect” of MRL in regard to joint adhesiveness. Our findings 4-weeks post injury are consistent with previous studies showing tissue-driven improved healing and suggest that the systemic environment contributes to the overall healing process.