Background: We hypothesize that the expression of proapoptotic and antiapoptotic molecules and cytokines is dependent on the distance from the torn supraspinatus tendon edge and this expression may influence its potential for healing. The aim of this work is to evaluate the expression of proapoptotic Bax molecule and caspases 3, 8, and 9; antiapoptotic Bcl-2 molecule; and proinflammatory tumor necrosis factor (TNF) α and anti-inflammatory interleukin 10 (IL-10) in 3 sections taken from a 1-cm section of the edge of a torn supraspinatus tendon: 3 mm distal and 3 mm proximal, as well as the remaining 4-mm middle section between them.
Methods: Nine patients, with a mean age of 58 years, were included in the study. All fulfilled strict inclusion criteria regarding the morphology of the tear and reconstruction technique. Samples were taken from the ruptured supraspinatus tendon at the time of arthroscopic repair. Quantitative real-time polymerase chain reaction assay was used for analysis.
Results: The expression of caspases 9, 8 and 3; Bax; and TNF-α significantly decreased from the distal to the proximal parts of the tendon edge (P < .05). However, a significant increase in Bcl-2 and IL-10 expression was also found in the same direction (P < .05).
Conclusions: Tenocytes can reduce the expression of proapoptotic caspases 3, 8, and 9 and Bax, as well as proinflammatory TNF-α, by increasing the expression of Bcl-2 and IL-10 within 1 cm of the supraspinatus edge in a distal to proximal direction. Resection 4 to 7 mm from the edge of the torn supraspinatus tendon may enhance the healing process by reaching a reasonable compromise between molecular homeostasis of apoptotic and inflammatory processes and mechanical aspects of rotator cuff reconstruction.
Keywords: Apoptosis; cytokines; homeostasis; supraspinatus tendon resection.
Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.