Aim: We hypothesize that anabolic steroid administration enhances matrix remodelling and improves the biomechanical properties of bio-artificially engineered human supraspinatus tendons (BATs).

Method: BATs were treated either with nandrolone decanoate (NLS group, n=18), stretching (LNS group, n=18), or both (LS group, n=18). A control group received no treatment (NLNS group, n=18). BATs’ contractility was assessed by daily scanning and two dimensional analysis. Cytoskeletal organization was evaluated microscopically with DAPI and rhodamine phalloidin staining. Matrix metalloproteinase-3 (MMP-3) levels – an indicator of matrix remodelling – were discerned by ELISA assay, and biomechanical properties by load-to-failure testing.

Results: The LS group showed greatest contractility and the best-organized actin cytoskeleton when compared to the other groups. On the second and third day of treatment, MMP-3 levels in the LS group were significantly greater than those of NLNS group and greater than NLS and LNS groups. The biomechanical properties (load to failure, ultimate stress, ultimate strain, elastic modulus, and energy to failure) in the LS group were significantly improved when compared to NLNS and NLS (p< .05) groups and 26–48% greater than those in LNS group.

Conclusions: Nandrolone decanoate and load act synergistically to increase matrix remodelling and biomechanical properties of bioengineered human supraspinatus tendons. Carefully prescribed and monitored, anabolic steroids may have an important adjunct role in postoperative healing and rehabilitation of repaired rotator cuff tendons. More research is necessary to fully evaluate the safety and efficacy of anabolic steroids in this application.

Aim: We hypothesized that anabolic steroid, combined with substrate strain upregulates expression of gap junction protein Connexin 43 (Cnx43) and increases cell-to-cell communication in human supraspinatus tendon cells.

Methods: Human supraspinatus cells were isolated and cultured in nutrient media arranged into 4 groups: 1) non-load, non-steroid (NLNS, n=12); 2) non-load, steroid (NLS, n=12); 3) load, non-steroid (LNS, n=12); and 4) load, steroid (LS, n=12). Steroid and load groups were cultured in 100Nm nandrolone decanoate and loaded at 1% elongation daily for 5 days, respectively. On day five of treatment, cells examined for immunocytochemistry. Cells were also subjected to mechanical stimulation by micro-pipette indentation and the intracellular calcium concentration ([Ca2+]ic) was quantitated using fluorescence microscopy. Numerous parameters were calculated: a) mean average response to stimulation, b) mean peak [Ca2+]ic, c) time of Ca2+ wave propagation, d) spontaneously responding cells prior to stimulation, and e) cell oscillation after stimulation (an indicator of cell toxicity).

Results: The LS group demonstrated the greatest density of Cnx43 in comparison to the other groups. Also, the LS group cells showed a significantly greater mean peak [Ca2+]ic and a significantly decreased propagation time, compared to the values of the other groups (p< 0.05).

Conclusions: Anabolic steroid, when combined with passive stretch, upregulates gap junction protein Cnx 43 and significantly increases calcium signalling in human supraspinatus tendon cells. When carefully prescribed and monitored, anabolic steroids may increase intercellular calcium signalling and may enhance the healing process of deficient rotator cuff tendons. More research will be necessary to fully evaluate the safety and efficacy of anabolic steroids for this application.