改良钛支架人工角膜生物相容性的实验研究

目的 探讨改良钛支架人工角膜的生物相容性和角膜生物愈合的过程.方法 实验研究.设计与制备改良钛支架人工角膜,钛支架采用喷砂、羟基磷灰石涂层处理,镜柱用聚甲基丙烯酸甲酯为原料按设计好的图纸手工磨制.将18只正常新西兰白兔采用单纯随机抽样方法分为A、B、C组,每组6只.18只新西兰白兔角膜碱烧伤模型采用单纯随机抽样方法分为E、F、G组,每组6只.其中A、E组和B、F组兔右眼角膜基质层内分别植入改良支架和对照支架(无涂层),C、G组仅做角膜板层切口;另取4只(分别为2只正常动物模型、2只碱烧伤模型)即D、H组分别作为空白对照;术后1、3个月取材,取出支架做拉出实验和扫描电镜检查;角膜组织行苏木素-伊红(HE)染色、透射电镜检查.另取8只兔(其中2只碱烧伤模型)植入改良支架,3个月后植入镜柱.两组剪切力比较采用t检验.结果 改良后的人工角膜支架表面呈鳞片状微孔结构,植入兔角膜反应轻,术后1、3个月取材,组织学检查见A、E组支架与角膜界面处成纤维细胞数多于B、F组支架.3个月时拉出试验测定剪切力A与B组比较、E与F组比较差异均有统计学意义(t=3.297,P<0.05;t=4.237,P<0.05),改良支架植入角膜3个月后的剪切力较对照支架强.扫描电镜检查显示A、E组支架表面被细胞外基质包裹,而B、F组支架细胞附着量明显少.透射电镜检查显示支架周围的胶原纤维束紊乱,A、E组支架与角膜的结合方式垂直或成一定角度,结合更牢固.支架植入后碱烧伤模型组角膜基质较正常兔角膜组愈合延迟.结论 改良钛支架人工角膜促进了材料与组织界面愈合,无论正常还是碱烧伤动物体内,改良钛支架人工角膜提高了材料的生物相容性.

Biocompatible study of modified titanium skirt for keratoprosthesis

Objective The research is engaged in developing an improved titanium skirt for keratoprosthesis, the aim of this study was to evaluate biocompatible of keratoprosthesis of novel design.Methods The pure titanium skirt for keratoprosthesis with three hands were first Sandblasted, and then bioactive hydroxyapatite coated on Sandblasted titanium for keratoprosthesis by a acid-alkali chemical treatment. A total of 18 New Zealand white rabbits and 18 alkali burned rabbit corneas were respectively divided into three groups (Group A, B and C;Group E, F and G) with simple random sampling methods.The modified titanium skirt was inserted into the corneal stroma of Group A and E, and then the control skirt was inserted into Group B and F. Group C and H did not insert skirt as surgery control. The interfacial biointegration of skirt/cornea were examined under light microscopy by HE,TEM and SEM. The transparent center was implanted to rabbit corneas with modified titanium skirt after 3 months. Results Dense hydroxyapatite coating was deposited on the Sandblasted specimens by an acid-alkali chemical treatment. The number of corneal fibroblasts increased significantly in Group A compared with Group B, The extracellular matrix deposited on the surface of modified titanium skirt was more dense and tight than that of control skirt.There was a significant difference in the shear force of skirt among groups A and B (t = 3.297, P < 0.05 ), E and F(t =4.237, P <0.05),and taking out the skirt in Group A and E were more difficulty than that in Group B and F after 3 months. The observation of the tissue sections of modified skirt inserted eyes revealed that there were cells and collagen-like fibres perpendicular to or at an angle to the rough interface and the cellular function was extremely active, in accordance with the results of TEM. Compared with healthy host tissue, skirt/cornea healing after alkali burn was impaired. Conclusions Hydroxyapatite modified Sandblasted titanium skirt for keratoprosthesis can promote the interfacial biointegration of skirt and host cornea, no matter in healthy cornea or diseased cornea (alkali burn cornea). Hydroxyapatite coating improved the bioactivity of titanium.