负载EDTA络合剂微球缓释系统治疗金属离子异常的实验研究

摘要

目的 通过构建中空介孔氧化硅纳米微球(hollow mesoporous silica nanoparticles,HMSNs)以持续、有效、智能地控制载乙二胺四乙酸(ethylene diamine tetraacetic acid,EDTA)的释放,治疗金属内植物引起的体内金属离子异常增高.方法 制备对H+敏感的葫芦脲-HMSNs-EDTA:构建含有α-环糊精功能基团的HMSNs,通过葫芦脲末端的HS基团与α-环糊精的HS基团形成双二硫键作为“开关”.葫芦脲与α-环糊精通过二硫键相连构成阀门系统,就可以封堵二氧化硅孔道从而封闭EDTA.通过膝关节腔注射铬钴钼(CoCrMo)纳米微粒悬液构建体内铬、钴离子升高的大鼠模型.将大鼠模型随机分为3组:经腹腔注射生理盐水(对照组);经腹腔注射传统的“阀门系统”的药物缓释体(IgG-HMSNs-EDTA组);经腹腔注射H+敏感葫芦脲-HMSNs-EDTA缓释体(智能缓释系统组).在此过程中继续注射纳米颗粒悬液,观察大鼠血清铬、钴离子浓度的变化.结果 EDTA的释放曲线中H+浓度分组:2mmol/L＞1 mmol/L＞ 0.5 mmol/L＞ 0.1 mmol/L,H+浓度越高,药物释放越快,表明感受器确实随着H+浓度的变化来控制阀门;与安装传统阀门的缓释体相比,新型的智能缓释体中EDTA的释放更平缓,新型10周时EDTA残余百分比为82.04％,传统为49.78％.20周内,对照组由于未用EDTA治疗,金属离子浓度会持续、缓慢地升高,铬离子(1.08±0.07) μg/L,钴离子(41.14±0.79) μg/L;传统阀门组在8周内,金属离子迅速减少,并一度低于大鼠体内的正常值.随后,由于EDTA释放完毕,金属离子仍会出现异常增高,铬离子(0.61±0.52) μg/L,钴离子(28.72±16.93) μg/L.智能缓释系统组铬离子(0.65±0.13)μg/L,钴离子(29.68±3.24) μg/L,则更能有效、持续、精确地控制体内铬、钴离子的异常变化,差异具有统计学意义.结论 根据二硫键随H+浓度变化可发生断裂或重建的原理,应用葫芦脲-HMSNs-EDTA智能微球缓释系统来治疗金属内植物引起的铬、钴离子增高的患者,将更加精准、更加智能地控制药物的释放.%Objective To construct a new sustained-release system,hollow mesoporous silica nanoparticles (HMSNs),to control the release of ethylene diamine tetraacetic acid (EDTA) continuously,effectively and intelligently to treat the abnormal increase of metal ions in vivo.The disulfide bond can be broken or reconstructed with the change of H + concentration to realize the construction of "receptor",and the "valve system" is constructed by blocking cucurbituril and alpha-cyclodextrin through disulfide bond.Thus,the abnormal increase of chromium and cobalt ions in rats can be accurately controlled and maintained at normal levels.Methods HMSNs-EDTA sensitive to H+ was prepared.HMSNs containing functional groups of alpha-cyclodextrin were constructed.The disulfide bond was formed between the HS group at the end of cucurbituril and the HS group of alpha-cyclodextrin as a "switch".Cucurbituril and alpha-cyclodextrin are connected by disulfide bond to form a valve system,which can block silica channels and thus close EDTA.A rat model of elevated chromium and cobalt ions was established by intraarticular injection of CoCrMo nanoparticles suspension into the knee joint.Rat models were randomly divided into three groups:intraperitoneal injection of saline (control group),intraperitoneal injection of traditional "valve system" drug sustained release (IgG-HMSNs-EDTA group),and intraperitoneal injection of H+ sensitive cucurbituril-HMSNs-EDTA sustained release (intelligent sustained release system group).During this process,nanoparticle suspension was injected continuously to observe the changes of serum chromium and cobalt concentration in rats.Results From the release curve of EDTA,it was found that the higher the concentration of H + was,the faster the drug release was (H+ concentration group:2 mmol/L ＞ 1 mmol/L ＞ 0.5 mmol/L ＞ 0.1 mmol/L).It shows that the sensor does control the valve with the change of H+ concentration.Compared with the slow-release body without valve,the release of EDTA in the new intelligent slow-release body is gentler.Within 20 weeks,the concentration of metal ions in the control group increased continuously and slowly due to the absence of EDTA treatment (Chromium 1.08±0.07 ug/L and cobalt 41.14±0.79 ug/L).In the traditional valve group,the metal ions decreased rapidly within 8 weeks and were once lower than the normal values in rats.Subsequently,due to the release of EDTA,metal ions will still increase abnormally (Chromium ion 0.61 ±0.52 ug/L,cobalt ion 28.72± 16.93 ug/L).The intelligent sustained-release system group can more effectively,continuously and accurately control the abnormal changes of chromium and cobalt ions in vivo,and the difference is statistically significant (Chromium ion 0.65±0.13 ug/L,cobalt ion 29.68±3.24 ug/L).Conclusion According to the principle that disulfide bond can be broken or reconstructed with the change of H+ concentration,the application of cucurbituril-HMSNs-EDTA intelligent microsphere sustained release system to treat patients with increased chromium and cobalt ions caused by plants in metal will control the drug release more accurately and intelligently.The intelligent sustained-release system can not only avoid the side effects caused by the rapid and excessive release of drugs,which lead to the disorder of normal trace metal elements in vivo,but also prolong the treatment time,and can maintain the chromium and cobalt ions in rats at normal levels for a long time.