Estrogen deficiency has been shown to negatively influence rotator cuff tendon healing. Therefore, the addition of an estrogen-like-compound (ELC) in a non-estrogen deficient animal may improve the quality of a rotator cuff repair.
The purpose of this study was to evaluate the effects of an ELC, diethylstilbestrol (DES), on tendon healing in a murine rotator cuff repair model.Thirty-three male wild type mice (C57BL/6NJ) were randomly divided into three study groups. Group 1-unoperated mice with normal rotator cuff tendons. Groups 2 & 3 consisted of surgically repaired rotator cuff tendons; Group 2 (Repair Only) was the standard repair group (no DES injected), while Group 3 (Repair + DES) was the experimental repair group (injected with DES).
Comparing the maximal thickness of calcified fibrocartilage to uncalcified fibrocartilage, the ratios for the Control (intact tendon), Repair Only, and Repair + DES groups were 2:1, 0.9:1 and 1.7:1. RNA expression data demonstrated upregulation of chondrogenic, angiogenic and tendon modulation genes in the Repair Only group compared to Control (intact tendon) group (p<0.04 for all), and that addition of DES further increased the osteogenic, angiogenic, and tendon modulation gene expression compared to the Repair Only group(p<0.02).
Immunohistochemical analysis indicated that addition of DES further increased osteogenic, angiogenic and tendon maturation protein expression at the enthesis compared to standard repairs.
