Impact of alendronate on bone resorption at the bone-screw interface

AIM :To investigate the impact of alendronate on bone resorption of normal and ovariectomized rats at the bone-screw interface through radiographic and histologic findings.METHODS :Thirty-two female Wister rats with a mean body weight of 332 g(287-351 g)were divided into four groups at random.Rats in group C and D were ovariectomized.8 weeks later,the proximal one-third of the left tibia of all rats were inserted into self-drilling mini cortical screws.After operations,alendronate were used in group A and C and saline were given in group B and D.The rats were euthanized at 5 weeks after screws having been attached.Radiographic and histologic findings subsequently were analyzed.RESULTS :Radiographs confirmed that no osteolytic area was present around screws immediately after insertion,whereas 5 weeks after insertion,a wide and low-density area corresponding to the screw hole was evident in the saline groups compared with the alendronate groups.On histologic observation,the width of the fiber membrane and the number of TRAP-positive cells were decreased in the alendronate groups than those in the saline groups,and the difference was statistically significant.CONCLUSION :Alendronate effectly inhibits bone resorption of either normal or ovariectomized rats at the bone-screw interface in rats.