雷洛昔芬对OVX大鼠骨质疏松性骨折愈合的影响

摘要

目的 探讨骨质疏松性骨折愈合的特点以及雷诺昔芬对骨质疏松性骨折愈合的影响.方法 健康12 周龄雌性SD大鼠54只,随机分成假手术组(SHAM),卵巢切除+生理盐水组(OVX),卵巢切除+雷诺昔芬组(OVX+RAL),每组18只大鼠.卵巢切除术后8周,骨密度检测确认大鼠骨质疏松模型成功.选择开放性右侧股骨中段骨折模型,以克氏针行髓内固定股骨;骨折后8周,CR片记录大鼠骨痂的连续性以及骨折愈合情况,三点弯曲试验检测股骨的最大弯曲应力和最大弯曲载荷.取骨折术后4周和8周时骨痂,行HE染色,并记录骨小梁或小梁状骨所占体积比(BV/TV)表示.免疫组化染色检测骨痂中血管内皮生长因子(VEGF)表达.结果 CR摄片显示骨折后8周各组大鼠骨折连续性都较好,骨折对位对线好.大鼠骨折8周时最大弯曲应力和最大弯曲载荷,SHAM组和OVX+RAL组都明显优于OVX组,差异显著,有统计学意义.骨折4周时骨痂的HE染色中,OVX组原始小梁状骨中新生软骨细胞较多.OVX+RAL组和SHAM组8周时骨痂中BV/TV值明显高于OVX组.骨折4周时骨痂VEGF染色中,各组大鼠的骨痂内软骨细胞或骨细胞上存在一定量的VEGF表达,SHAM组和OVX+RAL组的细胞上VEGF表达量略高于OVX组;骨折8周时各组骨痂中的VEGF几乎无明显表达.结论 OVX大鼠骨痂成熟缓慢和早期骨痂内VEGF低表达,可能是骨折愈合能力下降的重要因素.雷诺昔芬可以促进骨痂成熟和早期骨痂中VEGF的表达,有利于OVX大鼠骨折愈合.%Objective to study the feature of osteoporotic fracture healing in OVX rats and the effect of raloxifene on the osteoporotic fracture healing. Methods 54 female SD rats, aged 12-week-old, were divided into three groups randomly : SHAM group, OVX group, OVX + RAL group. 8 weeks after ovariectomy operations, the model of osteoprosis in OVX rats were confirmed by bone densitometer. The rats were given an open fracture fixed with Kirschner wire in right middle femur. After 8-week healing process, the continuity of fracture was recorded by x ray and the maxium bending stress and load were recorded by biomechanical bending test. The 4-week and 8-week fracture calluses were given HE stain and Vascular Endothelial Growth Factor ( VEGF) histomorphological stain. The BV/TV of fracture calluses were analyzed through HE stain images. Results After 8-week healing process, the X ray showed there were good continuity of fracture. After 8-week healing process, the maximum bending stress and load of bone from SHAM group and OVX + RAL group were higher than OVX group with significant difference. HE stain of 4-week fracture calluses showed that there were more newborn chondrocytes in original trabecular bone in OVX group than OVX + RAL and SHAM group. The BV/TV of 8-week fracture calluses from OVX + RAL and SHAM group were higher than OVX group with significant difference. There were VEGF positive expression in chondrocytes and osteocyte in 4-week fractute calluses and very lower VEGF positive exprssion in 8-week frcature calluses. The VEGF expression in 4-week fracture calluses from SHAM and OVX + RAL group were higher OVX group. Conclusion The slower maturation of fracture calluses and lower expression of VEGF in early fracture calluses may be an important factor of bad quality of fracture healing in OVX rats. Raloxifen was beneficial to frature healing by promoting maturation of fracture calluses and expression of VEGF in early fracture calluses.