Poly-N-Acetyl Glucosamine (sNAG) Enhances Early Rotator Cuff Tendon Healing in a Rat Model

Rotator cuff injuries frequently require surgical repairs which have a high failure rate. Biological augmentation has been utilized in an attempt to improve tendon repair. Poly-N-acetyl glucosamine (sNAG) polymer containing nanofibers has been shown to increase the rate for healing of venous leg ulcers. The purpose of this study was to investigate the healing and analgesic properties of sNAG in a rat rotator cuff injury and repair model. 144 adult male Sprague-Dawley rats underwent a transection and repair of their left supraspinatus tendons. Half of the animals received a sNAG membrane on the tendon-to-bone insertion site. Animals were further subdivided, receiving 1 or 3 days of analgesics. Animals were sacrificed 2, 4, or 8 weeks post-injury. Animals sacrificed at 4 and 8 weeks underwent longitudinal in vivo ambulatory assessment. Histological properties were assessed at 2, 4, and 8 weeks, and mechanical properties at 4 and 8 weeks. In the presence of analgesics, tendons receiving the sNAG polymer had significantly increased max load and max stress at 4 weeks, but not at 8 weeks. Ambulatory improvements were observed at 14 days in stride length and speed. Therefore, sNAG improves tendon-to-bone healing in a rat rotator cuff detachment and repair model.