Frankewycz B, Bell R, Chatterjee M, Andarawis-Puri N. The superior healing capacity of MRL tendons is minimally influenced by the systemic environment of the MRL mouse.
Sci Rep 2023;
13:17242. [PMID:
37821476 PMCID:
PMC10567747 DOI:
10.1038/s41598-023-42449-8]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 09/10/2023] [Indexed: 10/13/2023] Open
Abstract
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.
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