[Effect of diphosphonates on bone tissue of the rat during hypokinesia]

The diphosphonate effect on bones was studied in Wistar male rats weighing about 200 g. The rats were kept for 60 days in small-size cages where their motor activity was diminished. Every day the rats were given per os 0.3% solution of 1-hydroxy-ethylene-1,1-diphosphonate (HEDP) containing 9 mg/kg phosphorus. In the course of hypokinetic exposure the rats developed generalized osteoporosis. Histomorphometric measurements demonstrated that the drug did not prevent mineral losses from the tubular bones (humerus, femur). However, the drug led to a complete bone mass recovery in the pelvic and a partial recovery in the sternum. The drug also produced a preventive effect on the population of cells-precursors of osteogenesis the number of which decreases significantly during hypokinesia.