Effect of Local Application of Alendronate and Parathyroid Hormone on Craniofacial Bone Repair - a Preliminary Study

Abstract This study aimed to evaluate the effect of two methods of local application of alendronate and parathyroid hormone (PTH) on bone repair and the systemic implications. A critically sized defect (5 mm) was created in the cranial region of twenty-five male Wistar rats, and the bone removed was particulated, and grafted back to the defect with different treatments. The animals were randomly divided into five groups: A1- bone graft immersion in alendronate solution (3 mg/kg) for 5 minutes; P1- bone graft immersion in PTH solution (20 µg); A2- weekly local applications of alendronate 1 mg/kg; P2- weekly local applications of PTH (20 µg); C- no drugs were used. The animals were euthanized 60 days after surgery. Cranial bone blocks were removed for histological, histomorphometric, and immunohistochemical analyses. MMP-2 and MMP-9 were used for immunolabeling. The kidneys, liver, and brain were also removed from all the rats for histological analysis. The data were submitted for statistical analysis with a level of significance of 0.05 (One-way ANOVA). The group C and group P2 presented a higher quantity of viable bone particles than the remaining groups. Groups A1, A2, and P1 presented with fewer viable bone particles than the control group, with a predominance of non-mineralized connective tissue. The histomorphometric analysis revealed no differences in relative bone area or MMP-2 or MMP-9 immunolabeling between the groups (p>0.05). Group A2 showed presence of fat in the liver consistent with hepatic steatosis. Changes in brain tissue were observed in groups A1 and P1.摘要 本研究旨在评估阿仑膦酸钠与甲状旁腺激素（PTH）两种局部给药方案对骨修复的效果及其全身影响。 本研究选取25只雄性Wistar大鼠，于其颅骨区域构建5 mm临界尺寸骨缺损，将术中取出的骨组织制成颗粒，经不同处理后回植至缺损部位。将大鼠随机分为5组：A1组：骨移植物于3 mg/kg阿仑膦酸钠溶液中浸泡5分钟；P1组：骨移植物于20 μg甲状旁腺激素溶液中浸泡；A2组：每周局部给予1 mg/kg阿仑膦酸钠；P2组：每周局部给予20 μg甲状旁腺激素；C组：不使用任何药物。 术后60天对所有大鼠实施安乐死，采集颅骨骨块进行组织学、组织形态计量学及免疫组织化学分析，采用基质金属蛋白酶-2（MMP-2）与基质金属蛋白酶-9（MMP-9）进行免疫标记。同时采集所有大鼠的肾脏、肝脏及脑组织进行组织学分析。 采用显著性水平为0.05的单因素方差分析（One-way ANOVA）对数据进行统计学处理。结果显示，C组与P2组的存活骨颗粒数量显著高于其余各组；A1、A2及P1组的存活骨颗粒数量均低于对照组，且以非矿化结缔组织为主要成分。 组织形态计量学分析显示，各组间相对骨面积、MMP-2及MMP-9免疫标记水平均无显著差异（p>0.05）。A2组肝脏可见脂肪沉积，符合肝脂肪变性的病理表现；A1组与P1组的脑组织可见形态学改变。