The Treatment of Muscle Atrophy After Rotator Cuff Tears Using Electroconductive Nanofibrous Matrices

Rotator cuff tears (RCTs) are a common cause of disability and pain in the adult population. Despite the successful repair of the torn tendon, the delay between the time of injury and time of repair can cause muscle atrophy. The goal of the study was to engineer an electroconductive nanofibrous matrix with an aligned orientation to enhance muscle regeneration after rotator cuff (RC) repair. The electroconductive nanofibrous matrix was fabricated by coating poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) nanoparticles onto the aligned poly(epsilon-caprolactone) (PCL) electrospun nanofibers. The regenerative potential of the matrix was evaluated using two repair models of RCTs namely acute and sub-acute. Sprague-Dawley rats (n = 39) were randomly assigned to 1 of 8 groups. For the acute model, the matrix was implanted on supraspinatus muscle immediately after the injury. The repair surgery for the sub-acute model was conducted 6 weeks after injury. The supraspinatus muscle was harvested for histological analysis 2 and 6 weeks after repair. The results demonstrated the efficacy of electrical and topographical cues on the treatment of muscle atrophy in vivo. In both acute and sub-acute models, the stimulus effects of topographical and electrical cues reduced the gap area between muscle fibers. This study showed that muscle atrophy can be alleviated by successful surgical repair using an electroconductive nanofibrous matrix in a rat RC model. Lay Summary and Future Work Rotator cuff tears of the shoulder are a common cause of pain and disability, and available treatments focus on minimizing pain as well as restoring function of the shoulder. In clinical settings, the success of either sub-acute or chronic rotator cuff tendon repair can be compromised by muscle functionality. This study showed the efficacy of an electroconductive nanofibrous matrix to reverse muscle atrophy after successful surgical repair in rat acute and sub-acute rotator cuff model. Future study will investigate the regenerative potential of the engineered matrix in a chronic rotator cuff tear model.