β磷酸三钙／聚乙烯醇水凝胶人工角膜兔眼植入实验研究

Experimental research on implantation of β-TCP/PVA keratoprostheses into alkali-burned cornea in rabbit

【摘要】目的探讨β磷酸三钙／聚乙烯醇复合水凝胶人工角膜的生物相容性，初步评价碱烧伤兔眼移植效果。方法10只新西兰大耳白兔编号为1～10号，均以左眼作为手术眼，建立碱烧伤角膜新生血管模型。人工角膜植入手术分两期进行：I期手术将人工角膜植入碱烧伤兔角膜板层囊袋内；3个月后行Ⅱ期手术（角膜前板层开窗术），钻切角膜中央前板层组织，暴露人工角膜光学区。观察术后人工角膜与兔角膜组织的生长愈合情况，眼前段光学相干断层扫描仪（OCT）立体观察眼前段解剖结构改变，并行组织学检查。结果10例实验兔均成功实施I期人工角膜植入手术。4号兔I期植人术后4周出现感染性角膜溃疡，基质溶解，终致人工角膜脱出。Ⅱ期术后，2号兔出现人工角膜后增生膜；7号兔术后3周发生人工角膜前增生膜；术后1周9号兔因腹泻死亡，其他兔眼术后3个月角膜中央光学区维持透明，荧光素染色无渗漏，眼压正常。组织学检查发现人工角膜裙边孔隙中纤维组织长人；眼前段OCT检查示人工角膜位于受体角膜层间，眼前段解剖结构无异常改变。结论β磷酸三钙／聚乙烯醇复合水凝胶人工角膜具有良好的生物相容性，其裙边空间网状结构有利于角膜纤维组织长入，对于治疗角膜盲具有潜在的临床应用前景。

Objective To evaluate the biocompatibility of β-TCP/PVA keratoprosthesis and its therapeutic effects on the alkali-burned cornea in rabbit. Methods Firstly the models of alkali-burned cor- nea were induced by putting the filter paper dipped in 1 mol/L NaOH solution on whole cornea of left eyes in 10 New Zealand white rabbits. β-TCP/PVA keratoprosthesis was implanted into these model cornea by two stages. At stage I, a superior half-thickness dissection was made from sclera, 1.5 mm posterior to the limbus, extended into the cornea and formed an intralamellar pocket, the superior flap was retracted inferiorly and then a 3 mm central opening was created. The device was implanted into the pocket, centering the optic over the posterior opening. After 3 months, stage II surgery was performed to expose the optic by removing the central lamella. The reeepient cornea and anterior segment findings were clinically observed and evaluated. The dissected corneal tissues were examined pathologically. Results All the keratoprosthesis remained in situ after stage I procedure. Corneal perforation caused by inflammatory occurred in No. 4 rabbit 4 weeks after stage I. The diffuse white posterior membrane was found in No. 2 eye and the anterior membrane was seen in No. 7 operative eye several weeks after stage I1 surgery. No. 9 rabbit died from a diarrhea. Others,implants had been retained,with no severe complications, such as extrusion, stromal malting or aqueous leakage. The intraocular pressure of all eyes was just in normal range. Fibroblasts migration into the skirt of the implants was found. The normal anatomical structure in implanted eyes was noted by anterior segment OCT. Conclu- sion β-TCP/PVA keratoprosthesis has good tissue biocompatibility, its skirt is helpful to fibroblasts migra- tion. It is predicted that the device will has potential application prospects on the solution for corneal blind- ness in the future.