ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of local application of zoledronic acid (ZA) on the expression of type I collagen and vascular endothelial growth factor (VEGF).</p><p><b>METHODS</b>Fifty-four male Wistar rats were divided into ZA group, gelatin sponge group, and blank control group after one-side tooth extraction. The expression of type I collagen and VEGF were detected with SP immunohistochemistry method 1, 2 and 4 weeks after operation.</p><p><b>RESULTS</b>The gray value of type I collagen in ZA group (60.00 ± 1.81, 63.47 ± 3.02) was lower than those in gelatin sponge group (68.58 ± 2.90, 71.15 ± 5.57) and blank control group (69.16 ± 9.63, 72.50 ± 4.10, P < 0.05) in the 1 and 2 week. In the ZA and gelatin sponge groups, the gray values of type I collagen were higher in the 4th week than in the 1st and 2nd week (P < 0.05). The expression of VEGF was higher in ZA group (69.93 ± 2.74) than in gelatin sponge group (60.86 ± 4.79) and blank control group (61.52 ± 2.28) in the 1st week (P < 0.05). There was significant difference in VEGF expression between the 2nd week and 1st and 4th week (P < 0.05).</p><p><b>CONCLUSIONS</b>Local application of ZA could enhance the expression of type I collagen but inhibit the expression of VEGF in the early stage.</p>