Bone marrow-derived cells from the footprint infiltrate into the repaired rotator cuff

• Published in: Journal of shoulder and elbow surgery 2013-02, Vol.22 (2), p.197-205
• Main Authors: Kida, Yoshikazu, MD, Morihara, Toru, MD, Matsuda, Ken-Ichi, PhD, Kajikawa, Yoshiteru, MD, Tachiiri, Hisakazu, MD, Iwata, Yoshio, MD, Sawamura, Kazuhide, MD, Yoshida, Atsuhiko, MD, Oshima, Yasushi, MD, Ikeda, Takumi, MD, Fujiwara, Hiroyoshi, MD, Kawata, Mitsuhiro, MD, Kubo, Toshikazu, MD
• Format: Article
• Language: English
• Subjects: Animals; Biomechanical Phenomena; biomechanical strength; Bone Marrow Cells - physiology; bone marrow-derived cells; Cell Movement; Disease Models, Animal; footprint; GFP; Humerus - surgery; Mesenchymal Stromal Cells - physiology; Orthopedics; Rats; Rotator Cuff - physiopathology; Rotator Cuff - surgery; Rotator Cuff Injuries; Rotator cuff repair; supraspinatus; Wound Healing - physiology
• ISSN: 1058-2746; 1532-6500
• DOI: 10.1016/j.jse.2012.02.007

Background Cells from the bone marrow are considered important during the rotator cuff repair process, but the kinetics of bone marrow-derived cells in this process is unknown. Purpose To analyze the kinetics of bone marrow cells during the rotator cuff repair process, to review whether or not they are histologically involved in rotator cuff healing, and to analyze the biomechanics of the repaired tissues. Methods Bone marrow chimeric rats that express green fluorescent protein (GFP) only in bone marrow- and circulation-derived cells were created. Bilateral supraspinatus tendons were separated from the greater tuberosity of the humeral head to produce a rotator cuff transection model. Drilling into the bone marrow was performed in the greater tuberosity of the right humerus and the supraspinatus tendon was repaired (drilling group), while the supraspinatus tendon was repaired on the left shoulder without drilling (control group). We examined the histology of the rotator cuff, the ultimate force-to-failure, and the proportion of GFP-positive cells in the repaired rotator cuff at 2, 4 and 8 weeks after surgery. Results Mesenchymal cells were observed in the repaired rotator cuff at 2 weeks in both groups. There were more GFP-positive cells in the drilling group than the control group at 2, 4 and 8 weeks. The ultimate force-to-failure was significantly higher in the drilling group than the control group at 4 and 8 weeks. Conclusion Bone marrow-derived cells passed through holes drilled in the humerus footprint, infiltrated the repaired rotator cuff and contributed to postsurgical rotator cuff healing.