Background The primary management for nasolacrimal duct obstruction is the combination of lacrimal duct probing with lacrimal duct stent implantation.However,conventional implant is undegradable.New degradable lacrimal duct prosthesis based on biopolymer materials is a research hotspot.Objective This study described herein a preparation method of novel degradable lacrimal duct prosthesis and its application.Methods A new degradable lacrimal tube stent was prepared with compound of poly L lactic acid (PLLA) and polycaprolactone (PCL) (6:4) and 15％ polyethylene glycol (PEG).Thirty-two Japanese rabbits aged 3-4 months were randomized into postoperative 1-week group,postoperative 4-week group,postoperative 8-week group and postoperative 16-week group.The degradable lacrimal tube stents were inserted into the lacrimal ducts of the left eyes of the rabbits.The prosthesis was removed in corresponding time points according to grouping,and the integrity and weight of the prosthesis were evaluated.The mucosal findings of the operative eyes were examined under the endoscope,and the histopathological and inflammatory reaction was observed by hematoxylin & eosin stain.The ultrastructure of the lacrimal mucosal surface was examined under the scanning electron microscope.The use and care of the rabbits complied with the Regulations for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission.Results The new degradable PLLA:PCL+15％ PEG lacrimal duct stents were smooth,flexible and hydrophilic tubes.The removed tubes were intact in the postoperative 1-week group,however,the rupture of the tubes appeared in the postoperative 4-week group,while discrete pieces of the tubes were seen in the postoperative 16-week group.The weight-loss rates of the tubes were (13.44±6.59)％,(23.96±6.33)％,(55.08-± 6.55) ％ and (78.00±8.74) ％ in the postoperative 1-week group,postoperative 4-week group,postoperative 8-week group and postoperative 16-week group,respectively,and the weight-loss rate of the tubes was significantly higher in the postoperative 16-week group than those in the postoperative 8-week group (q =4.27,P＜0.05).No significant difference was found in the weight-loss rate of the tubes between postoperative 1-week group and postoperative 4-week group (q =1.71,P＞0.05).The edema,hyperemia and mild proliferation of the lacrimal mucosal were exhibited in the eyes of the postoperative 4-and 8-week groups,and the mucosal findings were almost normal in the eyes of the postoperative 16-week group under the endoscope.Histopathological examination showed a large number of inflammatory cells in the postoperative 1-,4-and 8-week groups.However,few inflammatory cells were seen in the postoperative 16-week group.Mucosal folds,microvillus decrease and disorder were displayed in the lacrimal duct of the postoperative 8-week group,and no evident abnormality was seen in the lacrimal duct mucosal surface.No postoperative complication occurred in all the rabbits.Conclusions PLLA:PCL+15％ PEG lacrimal duct stent has an appropriate degradation speed and good biocompatibility after implant in rabbits,and its decay period of mechanical strength could match lacrimal duct healing period.%背景 泪道探通术联合泪道支架植入是治疗泪道阻塞性疾病的主要方法,传统的非降解材料泪道支架存在需二次手术取出及并发症较多的缺点,基于可降解生物高分子材料的泪道支架及其应用是相关领域的研究热点. 目的 采用高分子可降解生物材料构建可降解泪道支架,并观察其植入兔泪道后的生物降解性和生物相容性.方法 与华中科技大学化学研究院共同研制左旋聚乳酸:聚己内酯+15％聚乙二醇中空管状可降解材料的泪道支架.采用计算机随机数字分配法将3～4月龄清洁级日本大耳兔32只随机分为术后1、4、8和16周组,将泪道支架植入实验兔左眼泪道,分别于相应时间点取出植入的泪道支架进行称量和观察,评价各组泪道支架的形状,并计算支架的失重率;采用泪道内窥镜检查各组兔术眼泪道黏膜的术后反应情况;分别于上述时间点处死各组实验兔,制备泪道黏膜组织标本,分别采用苏木精-伊红染色于光学显微镜下行组织病理学检查及激光扫描电子显微镜下行黏膜表面的超微结构观察. 结果 制作的可降解泪道支架为光滑、柔韧的亲水乳白色中空管道,术后1周组术眼取出的泪道支架完整,术后4周组可见泪道支架管口劈裂,术后16周组泪道支架断裂成不连续的碎片.术后1、4、8和16周组支架失重率分别为(13.44±6.59)％、(23.96±6.33)％、(55.08±6.55)％和(78.00±8.74)％,其中术后16周组泪道支架失重率最高,与术后8周组比较差异有统计学意义(q=4.27,P＜0.05),而术后1周组与术后4周组间差异无统计学意义(q=1.71,P＞0.05).泪道内窥镜检查可见术后4周组、术后8周组术眼黏膜水肿、充血和轻度增生,术后16周组术眼黏膜表现接近正常.组织病理学检查显示,术后1、4、8周组术眼泪道固有层大量炎性细胞浸润,术后16周组术眼泪道黏膜固有层仅见少量炎性细胞.激光扫描电子显微镜检查显示,术后8周组术眼泪道黏膜表面有不同程度的皱褶,表面微绒毛数量减少,排列紊乱,术后16周组术眼泪道黏膜上皮细胞表面微绒毛长度和数量增加,黏膜基底结构完整.各组兔眼均未见术后并发症. 结论 可降解泪道支架植入兔眼后对泪道黏膜的刺激性小,损伤轻微,具有较好的生物可降解性、生物相容性及生物力学特性.
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