To evaluate the biomechanical changes in rat trochanteric region after drug treatment, it was necessary first to produce a trochanteric fracture. Materials and methods Development of a new breaking test for the trochanteric region of

the rat femur A novel mechanical loading configuration was developed to measure the strength of the trochanteric region of the femur, according to the design of one of the authors (K.M. Stuermer). The left and right femurs of non-OVX rats were tested in a direction vertical to the greater trochanter. Temsirolimus cell line The mTOR inhibitor review femoral head was fixed in a 4 mm deepening at one end of the system, while the femoral shaft was horizontally positioned between two metallic movable rolling cylinders. The distal end of the femur was in contact with the aluminum plate without any rigidity. The lesser trochanter did not come into contact with the aluminum plate at all because of a groove made to allow for free movement. The angle between the femoral shaft and the horizontal line was nearly 0°. Force was applied vertically to the greater trochanter using a roller stamp (Fig. 1a–c). Fig. 1 a–c The new breaking test Selleckchem MM-102 is designed to produce trochanteric fractures for studying of biomechanical strength of trochanteric region of rat femur (here femur of Sprague–Dawley

rat). The femoral head was fixed in a 4-mm deepening on the other end of the system. The femoral shaft was horizontal between two metallic movable rolling cylinders. The distal end of the femur was in contact with the aluminum plate without any rigidity. The force was applied with a ZWICK-testing machine, type 145660 Z020/TND (Zwick/Roell, Ulm, Germany) The

force was applied with a ZWICK-testing machine, type 145660 Z020/TND (Zwick/Roell, Ulm, Germany). The measurement range was from 2 to 400 N, at a relative accuracy of 0.2% at 0.4% nominal force (FN). During the bending and breaking test, the femur was allowed to move longitudinally as it was dynamically fixed between the two roller clamps. The stamp was driven down to the greater trochanter until the bone was broken. Thalidomide Displacement and load were recorded, and ultimate strength (maximal load, N), stiffness (slope of the linear part of the curve, representing elastic deformation, N/mm), and the yield load were calculated. Fifteen pairs of right–left femurs of non-OVX rats were studied with this new breaking test before starting the comparative bioassay. Each bone and its contralateral partner underwent the breaking test on the same day, and the test order of bones was random. All bones were analyzed by the same operator. Comparative bioassay Experimental animals and substances The experiments were carried out using 44 3-month-old female Sprague–Dawley rats fed with a standard diet ad libitum.