The Effect of Estrogen-Like Compound on Rotator Cuff Tendon Healing in a Murine Model.

Abstract

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. This article is protected by copyright. All rights reserved.