Experimental surgical model in osteoporosis study.

To induce osteoporosis in animals many different experimental models are suggested. Experimental animal models play an important role in improving the knowledge of the aetiology, pathophysiology, diagnosis, and preventive and therapeutical techniques regarding osteoporosis. These experimental models permit thorough and standardized data that would be difficult to obtain by experimental clinical studies because of the difficulty of evaluating the differences that exist among patients. The choice of an in vivo experimental model is conditioned by a lot of factors: the reliability, the reproducibility, the feasibility and often some factors linked to equipment and costs which are also very important. In the present study some experimental models are examined and discussed, and in particular an experimental surgical model, that was performed in the Department of Experimental Surgery of the Rizzoli Orthopaedic Institute, is described. Female Sprague-Dawley rats, 40 or 50 weeks old, 350 +/- 20 g b.w., underwent bilateral oophorectomy in order to obtain an oestrogen deficiency. During the postoperative period the animals were maintained at the same housing conditions and diet. Fourteen days after oophorectomy it was possible to observe an osteopenia, that became progressively more pronounced up to 100 days. Till now this model permitted the comparative evaluation of different therapeutical treatments in such a diffuse and still debated pathology. Many are the experimental models adopted for comparative experimental studies of osteoporosis. Our model can induce a constant decrease of bone mass both in 50 and in 40 week old rats.