Flexor tendon repair

At 10–12 weeks of age, mice underwent complete transection and repair of the flexor digitorum longus (FDL) tendon in the hind paw as previously described [5]. Briefly, mice received an injection of sustained-release buprenorphine (1mg/kg). Next, they were anesthetized with Ketamine (60 mg/kg) and Xylazine (4 mg/kg). To reduce chances of rupture at the repair site, the FDL tendon was first transected at the myotendinous junction, and the skin was closed with a 5–0 suture. MTJ transection results in a transient decrease in loading, with reintegration of the MTJ observed by D7-10 post-surgery. Following sterilization of the surgery region, a small incision was made on the posterior surface of the hind paw, the FDL tendon was located and completely transected using micro spring-scissors. The tendon was repaired using an 8–0 suture and the skin was closed with a 5–0 suture. Following surgery, animals resumed prior cage activity, food intake, and water consumption.