可注射型磷酸镁自固化骨水泥修复大鼠股骨髁骨缺损的实验研究

Experimental study of injectable magnesium phosphate self-curing cement for repairing femoral condylar bone defects in rats

背景在过去几十年中,各种合成骨支架已被开发并应用于骨缺损。然而由于较差的降解性能或骨诱导能力,无法被广泛应用。磷酸镁骨水泥(magnesium phosphate cement,MPC)由于其出色的性能近年来备受人们关注。目的探究可注射型磷酸镁骨水泥的生物相容性及其修复股骨髁骨缺损的效果。方法使用酸碱反应制备磷酸镁骨水泥;采用万能试验机和称重法检测MPC的力学强度和可注射性,通过维卡仪测定MPC的凝固时间,采用扫描电镜对材料进行表征。采用CCK-8法和活死染色检测MPC的细胞相容性;MPC修复大鼠股骨髁直径2.5 mm骨缺损。实验分组按植入物的不同分为空白组、磷酸钙骨水泥(calcium phosphate cement,CPC)组、硫酸钙骨水泥(calcium sulfate cement,CS)组、磷酸镁骨水泥组,每组6只8周龄SD大鼠。术后4周、8周取材,对大鼠股骨髁标本进行微型计算机断层扫描(micro computed tomography,Micro-CT)分析,评估缺损区骨再生情况;标本切片后行HE染色、Masson三色染色,观察各组缺损区骨再生情况。结果成功制备出可注射型磷酸镁自固化骨水泥。MPC抗压强度为(36.25±0.72)MPa,可注射性为98.87%±0.29%,凝固时间为(15.16±0.32)min。扫描电镜结果显示,水化产物MgKPO_(4)·6H_(2)O表现为层片状,堆积紧密。CCK-8和死活染色结果显示,与空白组相比,MC3T3-E1细胞在MPC组高浓度浸提液中的活力略有下降;Micro-CT扫描结果显示,MPC、CS和CPC均未引起明显的感染现象,三者表现出明显不同的降解速度。组织学分析结果显示,各组支架植入大鼠股骨髁后,均无明显的炎症反应,骨组织未出现坏死。结论MPC具有良好的可注射性、力学强度和生物相容性,在骨修复过程中表现出更为合适的可降解性能,可用于修复SD大鼠股骨髁骨缺损。

Background In the past decades,various synthetic bone scaffolds have been developed and applied to bone defects.However,due to poor degradation properties or osteoinductive ability,it cannot be widely used.Magnesium phosphate cement(MPC)has received much attention in recent years due to its excellent properties.Objective To investigate the biocompatibility of injectable magnesium phosphate cement and its effect in repairing bone defects in the femural condylar.Methods Magnesium phosphate bone cement was prepared by acid-base reaction;Mechanical strength and injectability of MPC were tested by universal testing machine and weighing method,The setting time of MPC was determined by Vica apparatus,and the material was characterized by scanning electron microscopy.The cytocompatibility of MPC was detected by CCK-8 method and live-dead staining;MPC was used to repair femoral condyle defect with diameter of 2.5 mm in rats.Experimental groups were divided into blank group,Calcium phosphate cement(CPC)group,Calcium sulfate cement(CS)group and magnesium phosphate cement group according to different implants,with 6 SD rats in each group.The specimens were taken at 4 and 8 weeks after surgery and were analyzed by Micro-CT to assess bone regeneration in the defective area;HE staining and Masson trichrome staining were performed to observe the bone regeneration in the defect area of each group.Results An injectable magnesium phosphate self-curing cement was prepared successfully.MPC had a compressive strength of(36.25±0.72)MPa,an injectability of 98.87%±0.29%and a setting time of(15.16±0.32)min.The results of SEM showed that the hydration product MgKPO_(4)·6H_(2)O exhibited a lamellar shape with tight accumulation.The results of CCK-8 and live-dead staining showed that the activity of MC3T3-E1 cells in the high concentration extract of MPC group decreased slightly compared with the blank group;The results of Micro-CT scan showed that MPC,CS and CPC did not cause obvious infection,and all three showed significantly different rates of degradation.The results of histological analysis showed no significant inflammatory reaction and no necrosis of bone tissue in all groups after scaffold implantation into the femoral condyles of rats.Conclusion MPC has good injectability,mechanical strength and biocompatibility,and shows more suitable degradable behavior during bone repair,and can be used to repair femoral condylar bone defects in SD rats.