利福平-壳聚糖-海藻酸钙缓释微球在兔脊柱结核模型中的作用

Effects of rifampin-chitosan-calcium alginate sustained release microspheres in spinal tuberculosis models in rabbits

目的 观察利福平-壳聚糖（CS）-海藻酸钙（CA）纳米缓释微球在体内外释药效果及对兔脊柱结核模型的治疗作用.方法 合成利福平-CS-CA纳米缓释微球,对该微球进行形态学观察和测定其分布.取新西兰大白兔60只,随机分为A、B、C3组,通过兔腰椎椎体钻孔植入结核标准菌株H37Rv,建立兔脊柱结核模型.A组为对照组,不予用药.B组每只兔灌喂利福平每天12 mg/kg;C组每只兔灌喂利福平12 mg/（kg·d）,于第十腰椎旁给予缓释利福平微球（含利福平75 mg/kg）,观察3组兔模型在体内的释药性质及抗结核的作用效果.结果 （1）利福平缓释微球表面光滑,球体均匀度好,无粘连现象.（2）利福平微球的载药量为（34.58±1.47）％,包封率为（56.23±1.55）％.（3）A组兔模型腰5、6椎体均有明显破坏,椎间隙变窄,1只出现明显后凸畸形.5只兔腰大肌肿胀,腰大肌内可见低密度暗区.B组兔模型中6只兔腰5椎体和腰6椎体有较明显破坏,2只兔腰大肌肿胀.C组中7只兔腰6椎体上部有轻度骨质破坏,腰5、6椎间隙无明显改变,另3只兔观察至术后12周仍无明显影像学改变.（4）体内实验结果显示,将利福平微球按含利福平75 mg/kg的剂量植入C组兔模型椎旁后,椎旁肌和椎体内利福平浓度可维持在结核菌最低抑菌浓度（MCI）以上,持续到术后49 d.结论 通过椎体钻孔植入结核菌的方法可以建立兔脊柱结核模型,利福平-CS-CA纳米缓释微球的控释化疗可增加椎旁局部药物浓度,有效抑制结核杆菌生长.

Objective To investigate the drug release effect of rifampin （RFP）-chitosan （CS）-calcium alginate （CA） sustained release microspheres （Ms） in vivo and in vitro in the treatment of spinal tuberculosis model in rabbits.Methods RFP-CS-CA nano microspheres were synthesized,and their morphology was observer,and distribution was determined.Sixty New Zealand rabbits were randomly divided into three groups.the rabbit lumbar vertebral body through the insertion of the standard Tuberculose strainH37Rv,to establish a rabbit model of spinal tuberculosis.group A was the control group,each rabbit fed with rifampin 12 mg/（kg·d） in group B;each rabbit fed with rifampin 12 mg/（kg·d） ten para vertebral to rifampicin（rifampin release microspheres containing 75 mg/kg） in group C,drug release in vitro in nature and effect of antituberculosis in three groups were investigate.Results （1） Rifampin microspheres with smooth surface,sphere of good uniformity,no adhesion phenomenon.（2） Rifampin microspheres loading （34.58 ± 1.47）％,the entrapment efficiency was （56.23 ± 1.55）％.（3）Lumbar vertebrae 5,6 were obviously damaged in group A,narrowing of intervertebral space,1 obvious kyphotic deformity.5 rabbit psoas swelling,psoas muscle can be seen in the dark region with low density.Waist 5 vertebral body and waist 6 vertebral body of 6 rabbits has obvious damage in Group B,2 rabbit psoas swelling.In group C,waist 6 vertebral upper mild bone destruction,waist 5,6 vertebra clearance of 7 rabbits was not changed in group C,another 3 cases still no significant radio graphic changes after operation 12 weeks.（4） The in vivo experiment results show that,the rifampicin microspheres according to the dose implanted vertebral containing rifampin 75 mg/kg side,para spinal muscles and vertebral Nellie rifampin concentration can be maintained in TB minimum inhibitory concentration （MCI） above continuously in group C at 49 d after operation.Conclusion Drilling through vertebral implantation of mycobacterium tuberculosis can establish rabbit spinal tuberculosis model,RFP-CS-CA nano microspheres for controlled release chemotherapy can increase para spinal local drug concentration,effectively inhibit mycobacterial growth.