腺病毒介导NELL1促进骨溶解后的高质量骨再生

目的]研究具有特异性成骨作用的NELL1因子对磨屑所致骨溶解的影响,为骨溶解病的治疗提供一种新方案.方法]建立聚乙烯( Polyethylene,PE)颗粒诱导的颅骨骨溶解模型,68只Balb/c小鼠随机分成4组,即假手术组:术后1d颅顶皮下注射0.1 ml生理盐水；颗粒对照组:植入10 mg PE颗粒,术后1d注射0.1ml生理盐水；实验组(Ad - GFP - NELL1组):植入10 mg PE颗粒,术后1d注射0.1 ml( 109 pfu) NELL1荧光重组腺病毒载体( Ad - GFP - NELL1)；安慰剂组(Ad - GFP组):植入10 mg PE颗粒,术后1d注射0.1ml (109 pfu)荧光重组腺病毒载体( Ad - GFP).术后10 d采用活体荧光成像检测NELL1及GFP表达情况,并于处死后进行Micro - CT、组织学及生物力学的检测.结果]活体荧光证实实验组与安慰剂组小鼠颅顶有NELL1及GFP的高度表达,Micro - CT 3D图像观察实验组小鼠的颅骨骨溶解所致骨量丢失明显减少,所选兴趣区(ROI)的骨体积(BV)、骨密度(BMD)、骨小梁厚度(Tb.Th.3D)、骨表面积体积比(BS/BV)均明显优于对照组及安慰剂组.组织学切片观察到实验组的骨再生明显增多.另外,实验组小鼠的颅骨弹性模量(2.50±0.12)MPa]也明显优于对照组(0.60±0.20)MPa]及安慰剂组 (0.82±0.09) MPa](OP＜0.01).结论]腺病毒介导表达的成骨因子NELL1能通过促进高质量的骨再生平衡磨屑所致骨溶解的骨量丢失,是治疗骨溶解的一种潜在性解决方案.

Adenovirus-mediated NELL1 promotes bone regeneration in calvarial osteolysis model

Objective]To investigate the therapeutic effects of a craniosystosis-associated molecule,NEL-like molecule-1(NELL1;NEL,a protein strongly expressed in neural tissue encoding epidermal growth factor like domain) on osteolysis induced by polyethylene(PE)-particle debris. Methods]A murine calvarial osteolysis model was established with in vivo adenovirus(Ad)-mediated gene transfer.In total,68 female Balb/c mice were randomly assigned to 4 groups for treatment one day post-operation: SHAM surgery with 0.1 ml saline alone,PE particles with 0.1 ml saline,and PE-particles andadenovirus-green fluorescent protein with NELL1(Ad-GFP-NELL1,0.1 ml) or Ad-GFP(0.1ml) at 1×109 plaque-forming units/ml diluted in saline.GFP and NELL1 delivery in vivo after injection were certified by optical imaging at 10 days post-operatlon,and then all mice were sacrificed for analysis by 3-D micro-computed tomography(micro-CT),histology and biomechanical testing. Results]Exogenous NELL1 and GFP were expressed in the head for at least 10 days after Ad-GFP-NELL1 injection.Serial 3-D micro-CT images and testing of bone volume,bone mineral density,trabecular thickness,bone surface density revealed the new bone promoted with Ad-GFP-NELL1 injection could almost compensate the PE-induced osteolysis and regenerate significantly better than with PE and/or Ad-GFP treatment.The elastic modulus was significantly greater with Ad-GFP-NELL1 than with PE and/or Ad-GFP(P<0.01). Conclusion]Ad-GFP-NELL1 gene transfer effectively reversed the calvarial osteolysis model by promoting bone regeneration,and it may be a novel treatment for osteolysis.