磁共振技术检测透明质酸钠对钆喷酸葡胺角膜渗透性的影响

Evaluation of transcorneal permeability of hyaluronic acid-assistant Gd-DTPA using MRI

目的利用磁共振成像(MRI)及其造影剂,探讨加入增黏剂透明质酸钠对钆喷酸葡胺(Gd-DTPA)角膜渗透性的影响。方法 16只新西兰白兔按随机数字表法分为2组,每组8只兔,均取右眼为实验眼,分别点用质量分数23.45%Gd-DTPA滴眼液为Gd-DTPA组、23.45%Gd-DTPA+质量分数0.2%透明质酸钠滴眼液为透明质酸钠组,每5 min点眼1次,每次50μL,共6次。左眼为正常对照眼,不做任何处理。此后进行MRI连续扫描,观察用药前后兔眼结膜囊、前房、后房及玻璃体内示踪剂的信号变化。结果正常兔眼前房MRI平扫呈均匀低信号。Gd-DTPA组结膜囊信号在用药40 min消失,透明质酸钠组结膜囊内Gd-DTPA信号在用药后60 min消失。与Gd-DTPA组比较,透明质酸钠组结膜囊内和前房示踪剂信号增强明显,60 min时Gd-DTPA组前房信号增强率为19.63%,透明质酸钠组为53.42%。2组兔点眼后后房及玻璃体信号强度均无变化。结论透明质酸钠可提高与Gd-DTPA性质类似药物的角膜通透性,MRI能够在活体内动态、实时地检测滴眼液的角膜渗透性,是对传统药物代谢检测方法的补充。

Background To improve the permeability of eye drops in ocular tissue is key for enhancing the effectiveness of eye drug.Researches demonstrated that adhesion promotor can improve the intraocular permeability of eye drops.ObjectiveThe purpose of this study was to detect the corneal permeability of hyaluronic acid solutions with nuclear magnetic resonance imaging（MRI） and gadolinium-diethylene triamine pentaacetic acids（Gd-DTPA）.MethodsSixty-six clean New Zealand white rabbits were divided into two groups randomly and 8 rabbits for each.50μL of gadolinium-diethylene triamine pentaacetic acids（Gd-DTPA）（23.45%）,a tracker,was topically administered in the right eyes for 6 times at a 5-minute interval in Gd-DTPA group,and 23.45%Gd-DTPA with 2% hyaluronic acid eye drops was used at the same way in hyaluronic acid group.MRI scaning was performed in rabbits eyes before experiment and 20,40,60 and 80 minutes after use of drug.The signals of Gd-DTPA in anterior chamber,posterior chamber and vitreous body in different time points were assessed and compared between these two groups.ResultsThe low signal in the anterior chamber of normal rabbit eye was seen by MRI.In Gd-DTPA group,the tracker signal in conjunctival sac disappeared in 40 minutes after use of drugs.However,in hyaluronic acid group,the tracker signal was seen in the anterior chamber and the signal intensity was enhanced in conjunctival sac.Tracker was completely removed 60 minutes later in hyaluronic acid group,indicating that the clearance of Gd-DTPA in hyaluronic acid group was slower than that in Gd-DTPA group.The percent of tracker signal enhancement in anterior chamber was 19.63% in Gd-DTPA group and 53.42% in hyaluronic acid group.No tracker signal was detected in the posterior chamber and vitreous body in both groups under the MRI.ConclusionHyaluronic acid can improve corneal permeability of Gd-DTPA.MRI is a noninvasive,dynamic and real time complementary technique to traditional pharmacokinetic methods.