先天性γS基因突变小鼠晶状体的形态学和病理学改变

The anatomical and pathological changes in the crystalline lens of a congenital γS-crystallin gene mutated mouse model

目的了解先天性γS基因突变小鼠晶状体的形态学和病理学改变。方法采用先天性γS突变小鼠动物模型,其遗传方式为隐性遗传。将5周龄的突变小鼠和正常小鼠分为两组,扩瞳后进行眼部和肉眼生物裂隙灯显微镜照相。脊椎脱臼处死小鼠后摘除眼球,固定并制作组织病理石蜡切片,用HE染色后进行光镜观察。结果和正常小鼠相比,γS突变小鼠双眼都产生对称的核性白内障,晶状体核区完全被白色混浊所覆盖,而周边皮质透明。组织病理学上,突变小鼠的晶状体可出现Morgagnian(马氏)小体;前囊下皮质纤维排列疏松,出现空泡样改变;赤道部上皮细胞增殖明显,并向前后极迁移;核心部嗜伊红深染,纤维短缩,排列紊乱;后囊膜下出现空泡变性。结论γS基因突变影响了小鼠晶状体的正常发育,促进晶状体上皮细胞的增殖或使其向晶状体纤维细胞分化时脱核受阻,并直接或间接地影响晶状体纤维的排列,从而导致白内障的发生。

Objective To analyze the anatomy and histology of the crystalline lens in a congenital γS-crystallin gene mutated mouse model. Methods A recessive mouse model with spontaneous Crygs mutation in KUNMING outbred mice was used. Mutant mice and normal mice aged 5 weeks were the experimental group and control group, respectively. All mice underwent ocular observation and slit lamp microscope photography after pupil dilation. The mice were then sacrificed by a vertebro-dislocation method and the eyes were enucleated. The eyes were fixed and paraffin-embedded sections were stained with hematoxylin and eosin. The stained sections were observed under light microscopy. Results Compared to the normal group, the Crygs mutated mice had symmetric nuclear cataract in both eyes. The nucleus of the lens was completely covered by white opacities. However, the periphery of the lens was transparent. Histological examination of the lens in the mutant mice showed Morgagnian bodies. Superficial cortex fibers did not align tightly and seemed to have vacuole-like degeneration. Epithelial cells in the equatorial region seemed to overproliferate and migrate anteriorly and posteriorly. The nucleus of the lens was a deeply stained pink, with the shorter fibers losing their normal arrangement. Large vacuoles were observed undemeath the posterior lens capsule. Conclusion The mutated γS-crystallin gene can influence the normal development of the crystalline lens. It can accelerate the proliferation of the lens epithelium, or it can stop the karyorrhexis of lens epithelium from changing to fiber cells. In addition, it disturbs the arrangement of lens fibers either directly or indirectly, which leads to the formation of cataract.