Radiologische Analyse eines Knochendefektmodells zur Lokalapplikation von Medikamenten am osteoporotisch induzierten Rattenfemur - Eine Pilotstudie

Osteoporosis belongs to the worldwide endemic diseases caused by the sheer number of incidences. Due to the increase of life expectancy, the occurrence of Osteoporosis and therefore the osteoporosis induced fractures will increase within the following years. Consequently, the improvement of the prophylaxis, diagnostic and therapy of Osteopo-rosis belongs to the medical challenges of the 21st century. The outlined study examines for the first time the effect of a local application of Osteo-protegerin (OPG) into the fracture gap during fracture healing using the model of osteo-porotic rats (Wistar-Hannover). Supplementary, the experiment serves as a pilot study to verify the suitability of the method being used of the following main attempt. Three attempt groups had been included (ovariectomized rats without OPG (OV-OPG), ovari-ectomized rats with OPG (OV+OPG), non-ovariectomized rats without OPG (control-group), each n = 10). The rats had been given an osteotomic gap within the right femur (1mm), in which the OPG was implanted using a carrier matrix (Spongostan®). An ex-ternal fixator was used as osteosynthesis. After four weeks the rats had been eu-thanized. Post mortem the fracture areas had been analyzed by using quantitative computerized tomography (pQCT), imaging procedures (native x-rays, micro-computertomographie (µCT) as well as histological procedures (Toluidinblue-, Masson-Goldner-Trichrom-coloration). The plantation of the external fixator and the placing of the Spongostan® within the os-teotomic gap were easily installed and conducted without problems. The anaesthesia problems which appeared predominantly by ovariectomized rats, could most likely be traced back to a more slowly metabolism of the i.m. applicated anesthetic drugs refer-ring to higher body fat percentage. An offset of the femoral ends that were found by 10% of the animals underlines the importance of regular x-ray examinations in order to supervise the proper positioning of the external fixator. The highly defined 3D µCT pic-tures enhances a detailed view on the fracture gap. A more resilient infiltration of the Spongostan® and a conformation of bone braces caused a better bone healing within the OV+OPG group. The pQCT results imply that OPG by osteoporosis increases the bone surface and bone mass rather than the bone density. The histological analysis certified the µCT results and allowed an insight view on the proceeding within the bone fracture (cell infiltration, angiogenesis, infiltration of the Spongostan® , formation of bone tissue and bone braces, missing necrosis).The low occupation of sub-groups as well as the short test period of only four weeks limited the validity of the pilot study. Most likely, an increase in the test animal laboratory number as well as the duration of the main experiment will increase the efficiency of the OPG.