光学相干断层扫描血管造影(OCTA)在异种角膜移植供体选择中的应用研究

Application of optical coherence tomography angiography in donor selection in xenocorneal transplantation

目的利用光学相干断层扫描血管造影(optical coherence tomography angiography,OCTA)技术比较新西兰兔和猫角膜上皮、角膜全层厚度与人类的差别,探讨不同动物作为异种角膜移植实验模型的形态学依据。方法雄性新西兰白兔和雄性猫各12只,分为A、B两组,每组各12只,OCTA技术测量每组样本双眼角膜上皮和角膜全层的厚度,所得数据以瞳孔为中心,根据距离角膜中央区的距离不同,利用系统软件将角膜划分为17个区域。中央区角膜是角膜正中间直径为2 mm的区域,内环和外环直径分别是5 mm和6 mm。在内外环分别又分出八个区域:上方(S)、鼻上(SN)、鼻侧(N)、鼻下(IN)、下方(I)、颞下(IT)、颞侧(T)、颞上(ST),测量各区域角膜上皮和角膜全层厚度。比较新西兰兔和猫角膜上皮、角膜全层厚度与人类的差别。结果猫角膜上皮和角膜全层厚度均大于兔。角膜厚度:猫角膜全层是中央薄、周边厚,其中在T5、ST5、S5、SN5、N5区与中央区的厚度差异均有统计学意义(均为P<0.05),角膜上皮在ST5、S5、SN5区与中央区厚度的差异均有统计学意义(均为P<0.05);兔角膜全层同样为中央薄、边缘厚,其中在T5、IT5、IN5、N5、T6、N6区与中央区厚度差异均有统计学意义(均为P<0.05),角膜上皮ST5、S5、SN5、ST6、S6、SN6区与中央区厚度差异均有统计学意义(均为P<0.05)。与人类角膜相比,两种实验动物与人在角膜全层和角膜上皮厚度方面差异均有统计学意义(均为P<0.05)。结论猫角膜与人类角膜在角膜全层厚度和角膜上皮厚度及其分布方面具有相似的区域,同时,猫角膜全层厚度和角膜上皮厚度均较人类厚,这在异种角膜移植后的屈光调节中也具有优势。猫较兔更适合作为人类异种角膜移植的潜在供体。

Objective To compare the thickness of corneal epithelium and full-thickness of the cornea among New Zealand rabbits,cats and the human using optical coherence tomography angiography( O C T A) technology as to explore the morphological basis for different animals as experimental models of xenocorneal transplantation. Methods Totally selected 12 New Zealand male rabbits and 12 male cats w ere included in this study and divided into group A and B. T hen the thickness of corneal epithelium and fullthickness of the cornea of both eyes in the tw o groups w ere measured w ith O C T A technology,and according to the distance from the center of the cornea,t he cornea w as divided into 17 areas by System softw are. T he center of the cornea w as a diameter of 2 mm around the center of the cornea,w ith the inner ring and outer ring of 5 mm and 6 mm in diameter,respectively; and the inner and outer ring region w as again divided into 8 areas, including superior side( S),superior nose side( SN),nasal side( N), inferior nose side( IN), inferior side( I), inferior temporal side( IT),t emporal side( T),superior temporal side( ST). T hen the thickness of corneal epithelium and full-thickness of the cornea in each region w ere measured for comparing the difference of New Zealand rabbits' and cats' corneal thickness w ith the human's. Results T he thickness of corneal epithelium and full-thickness of the cornea of cats w ere both thicker than those of rabbits. T he full-thickness of the cats' cornea became thinner from the central to the peripheral side,and the difference of thickness betw een the T 5,ST 5,S5,SN5,N5 areas and the central of the cornea w as statistically significant( all P < 0. 05); the thickness of corneal epithelium in the ST 5,S5,SN5 areas w as significantly thicker than the central area( all P < 0. 05); And this w as true of the rabbits' full-thickness of the cornea,and the difference in the full-thickness of the cornea between the T5, IT5, IN5,N5,T6,N6 area and the central region was statistically significant( all P < 0. 05); meanwhile there were also significant difference in the thickness of corneal epithelium between the ST5,S5,SN5,ST6,S6,SN6 areas and the central area( all P < 0. 05). Additionally,t here were significant differences in the thickness of corneal epithelium and full-thickness of the cornea between the two experimental animals and humans( all P < 0. 05). Conclusion T he cornea of cats possesses similar regions in corneal full-thickness and epithelial thickness as well as the distribution to human cornea, so cats have superiority to the rabbits for the potential donor of xenocorneal transplantation in human beings.