Effect of simvastatin on rat supraspinatus tendon mechanical and histological properties in a diet-induced hypercholesterolemia model

Hypercholesterolemia is a common condition and is a risk factor for tendon rupture, specifically in the supraspinatus tendon. In the clinic, statins are commonly prescribed to lower cholesterol, but little information is available examining the effect of statin treatment on the musculoskeletal system. Therefore, the objective of this study was to determine the biomechanical and histological effects of statin treatment in a diet-induced hypercholesterolemia model. We hypothesized that hypercholesterolemic rats treated with statins would have improved tendon biomechanical and histological properties compared to hypercholesterolemic rats not receiving daily statin treatment. Thirty adult male Sprague-Dawley rats ate either high-cholesterol (HC) diet (n = 20) or normal chow (CTL, n = 10). After 6 months, a subset of HC rats began daily oral simvastatin dosing (HC+S) at 20 mg/kg. All rats were sacrificed after a total of 9 months (3 months of statin treatment) and evaluated for histology and mechanics. For mechanics, at the insertion region, HC+S group had increased tendon cross-sectional area decreased and modulus. No differences were noted in mechanical properties at the midsubstance. For histology, no differences were noted in the insertion region. In the midsubstance region, HC+S group had more spindle shaped cells. Our results suggest that 3 months of simvastatin treatment in a diet-induced hypercholesterolemia rat model alters some tendon mechanical and histological properties, although a strong conclusion in support of improved parameters cannot be drawn. Therefore, we conclude that simvastatin treatment does not negatively affect tendon properties. (C) 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.