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目的比较7种实验动物(BALB/c小鼠、豚鼠、新西兰大白兔、猫、狗、猪和牛)角膜的光镜和电镜下结构,探讨不同动物作为各种角膜实验模型的形态学依据。设计实验研究。研究对象BALB/c小鼠(8~12周)、豚鼠(350~450 g)、新西兰大白兔(2.5~3.5 kg)和成年猫、狗、猪、牛7种动物,各6只新鲜眼球。方法制作各种动物眼球的角膜光镜、电镜切片,分别对HE染色切片摄制成的彩色照片和电镜照片进行比较分析。主要指标角膜各层结构形态、厚度,有无前后弹力层,基底膜及半桥粒的特点。结果角膜厚度的变化趋势:兔、狗、猪、牛角膜是中央薄、边缘厚,与人相似;中央厚、周边薄者有豚鼠和猫;小鼠角膜中央到周边厚度变化不明显。中央角膜上皮层厚度:豚鼠与人最相似。角膜上皮层平均厚度、中央区全层厚度、角膜中央区及旁中央区基质层厚度:兔与人最接近。角膜缘厚度:牛与人最接近。角膜基质层平均厚度:狗与人最相近。角膜后弹力层厚度:牛与人最相近。角膜内皮层厚度、后弹力层与内皮层厚度比例:猪与人最接近。角膜内皮细胞直径:豚鼠与人最接近。光镜下,7种动物角膜上皮细胞形态:复层扁平细胞为长扁形,翼细胞为多角形,基底细胞为单层柱状细胞。光镜下均无法判断是否有前弹力层,基质层内胶原纤维排列整齐,无定型结构的后弹力层可辨认,内皮细胞为单层扁平细胞。电镜下,BALB/c小鼠和狗的角膜未见明确前弹力层,兔、猫、猪和牛角膜有前弹力层。豚鼠角膜因照片质量不佳,无法判断是否有前弹力层。BALB/c小鼠的后弹力层内可见条梭状特殊结构,牛的后弹力层呈条栅状条纹。各动物角膜的半桥粒平均直径(单位:μm)分别为小鼠0.16±0.01,兔0.18±0.02,猫0.27±0.06,狗0.19±0.08,猪1.72±0.08,牛1.13±0.82。半桥粒平均面积(单位:μm2)分别为小鼠0.03,兔0.04,猫0.09,狗0.05,猪3.76,牛2.09。BALB/c小鼠角膜半桥粒的直径和面积与人角膜最为接近。结论兔角膜拥有最多的与人角膜相近的测量指标,故7种动物中兔角膜在做角膜模型方面更有优势。其他动物则各有所长。
Objective To compare the morphological features of cornea of 7 experimental animals (BALB / c mice, guinea pigs, New Zealand white rabbits, cats, dogs, pigs and cattle) by light microscopy and electron microscopy. Design experiment research. The study included 7 animals, 6 eyes each from BALB / c mice (8-12 weeks), guinea pigs (350-450 g), New Zealand white rabbits (2.5-3.5 kg) and adult cats, dogs, pigs and cattle. Methods The corneal light microscope and electron microscope were used to make eyeballs of various animals. The color photographs and the electron micrographs of the HE-stained sections were compared respectively. The main indicators of the corneal structure of the various forms, thickness, with or without elastic layer, basement membrane and hemidesmosome characteristics. Results The trends of corneal thickness were as follows: rabbits, dogs, pigs and corneas were central thin, margin was thick and similar to human; central guinea pigs and cats were thinner and thinner around the center; Central Corneal Epithelial Thickness: Guinea pig is most similar to human. The average corneal epithelial thickness, the central area full thickness, central cornea and adjacent central stroma thickness: the closest rabbit and human. Corneal margin thickness: the closest cow and people. Corneal stroma average thickness: the closest dog and human. Corneal stretch thickness: cattle and people are the most similar. Corneal endothelial cortical thickness, ratio of posterior elastic layer to cortical thickness: closest to human. Corneal endothelial cell diameter: Guinea pig and human closest. Under light microscope, the morphology of seven kinds of animal corneal epithelial cells was as follows: the flattened flattened cells were long flat, the wing cells were polygonal, and the basal cells were single columnar cells. Light microscope can not determine whether there is a pre-elastic layer, stromal collagen fibers arranged in neat, amorphous structure of the elastic layer can be identified, endothelial cells as a single flattened cells. Under electron microscopy, there was no clear anterior elastic layer in the cornea of BALB / c mice and dogs, and an anterior elastic layer in rabbits, cats, pigs and bovine corns. Guinea pig cornea photo quality is poor, can not determine whether there is a pre-elastic layer. In the posterior elastic layer of BALB / c mice, a special spindle-like structure was observed. The posterior elastic layer of the BALB / c mice showed a bar-like streak. The average diameter of hemidesmosomes in each animal cornea was 0.16 ± 0.01, 0.18 ± 0.02, 0.27 ± 0.06, 0.19 ± 0.08, 1.72 ± 0.08, and 1.13 ± 0.82, respectively. Mean area of hemidesmosomes (unit: μm2) were 0.03 for mice, 0.04 for rabbits, 0.09 for cats, 0.05 for dogs, 3.76 for pigs, and 2.09 for cattle. The diameter and area of BALB / c mouse corneal hemidesmosome are the closest to that of human cornea. Conclusion The cornea has the most measurements of the human cornea, so the corneas of the 7 animals have more advantages in corneal modeling. Other animals have their own strengths.