兔泪腺摘除后的泪液分泌及其角膜上皮的形态学改变

Changes of Tear Secretion and Morphology of Corneal Epithelium after Lacrimal Gland Extirpation in Rabbits

目的观察摘除泪腺后,兔泪液S1T值、角膜荧光素染色和虎红染色的变化及其角膜上皮超微结构的变化,评估兔干眼症模型的建立。方法摘除兔泪腺和Harder氏腺,比较泪腺摘除前后S1T、角膜荧光素染色和虎红染色分值的变化,并在透射电镜下观察角膜上皮形态学的变化。结果泪腺摘除后平均S1T值(15.88±6.29mm/5min)低于摘除前的平均S1T值(20.25±5.52mm/5min),差别有统计学意义(P=0.0062)。平均角膜荧光素染色和虎红评分(分别为8.22±1.99和7.67±0.87)明显高于摘除前(分别为0.22±0.44和0.67±0.5),差别有统计学意义(两组均P<0.0001)。以上3个检查指标的变化说明摘除泪腺后出现水液性泪液分泌缺乏,导致角膜上皮点状剥脱,干燥及坏死。在形态学上泪腺摘除前后的角膜上皮也发生了明显的改变,透射电镜检查发现液化的表层上皮细胞,表层细胞膜破裂。以上的改变均符合干眼症的特征。结论摘除兔泪腺和Harder氏腺后兔泪液分泌减少,角膜上皮坏死,能有效形成泪液缺乏型干眼模型。

Objective To observe the changes of Schirmer I test value （SIT）, corneal fluorescein and rose Bengal staining, and morphological alterations of corneal epithelium after lacrimal gland extirpation in rabbits. To evaluate the characteristics of the rabbit dry eye model. Method The SIT value, corneal fluorescein and rose Bengal staining before and after lacrimal gland extirpation were graded. The cornea was taken for transmission electron microscopic examination. Result After lacrimal gland extirpation, the S1T was statistically significantly decreased （20.25 ± 5.52 mm/5 min before and 15.88 ± 6.29 mm/5 min after extirpation, P = 0.0062）. The average grade point of the corneal fluorescein and rose bengal staining （8.22 ± 1. 99 and 7.67 ± 0.87, respectively） was significantly higher than that before the model establishment （0.22 ± 0.44 and 0.67 ±0. 5, respectively, P 〈 0.0001 ）. The variation of the above mentioned three testing indexes indicated that tear deficient dry eye after the extirpation of lacrimal gland caused punctate erosions and necrosis of the corneal epithelium. Transmission electron microscopic observation revealed liquidation of superficial epithelial cells and break of basement membrane in the cornea after the model establishment. Those changes were characteristic of dry eye. Conclusion After lacrimal gland extirpation, the tear secretion decreases and punctate erosion and necrosis of corneal epithelium occurs. Thus, a rabbit model of dry eye with decresed tear secretion and punctate erosion and necrosis of corneal epithelium can be successfully established by lacrimal gland extirpation.