【作者】 马轶群；

【导师】 王传富；

【作者基本信息】 青岛大学 ， 眼科学， 2003， 博士

【摘要】 干眼症(Dry eye syndrome，Xerophthalmia)又名角结膜干燥症，是由于眼部和／或全身多种原因引起的泪腺低分泌而导致泪膜异常、眼表上皮干变的最常见眼科疾病之一。患者开始症状是灼烧感、异物感、干燥和畏光，随病情进展而加重，最终出现角膜溃疡甚至失明。1933年Henrik Sj(?)gren最早提出了眼干、口干和关节疼痛三联征，因而出现了干眼一词。现代干眼症定义是1995年Brewitt提出的，即：干眼症是由于外眼的天然功能和保护机制产生各种障碍，引起瞬目时泪膜不稳定的一种眼表疾病。近年研究发现干眼症发病与维生素A缺乏、炎症、免疫、细胞凋亡及性激素水平等有关，但目前该病的发病机制尚无定论。我国对干眼症的研究刚刚起步，尤其对发病机制尚无动物实验方面的报道，因此对其发病机制及治疗的研究具有重要意义。 动物模型是进行临床和基础研究的重要载体，根据干眼症的假定发病原因，如维生素A缺乏和雄激素水平降低，成功制作动物模型，是研究干眼症发病机制的基础。干眼症患者泪液分泌减少、泪膜稳定性下降、角膜表面染色，对干眼症动物模型进行眼表损害的诊断，可为临床诊断干眼病提供依据。 干眼症的特征性病理改变为泪腺萎缩、泪腺组织灶性淋巴细胞浸润增殖；角膜上皮层次增加、细胞形态不规则、细胞坏死脱落；结膜杯状细胞消失。超微结构见泪腺内质网破坏、线粒体呈空泡样变、角膜表层上皮微绒毛肿胀脱落。这些改变将导致泪腺分泌减少、角结膜上皮干变。因此进一步研究泪腺、角膜及结膜的组织病理及超微结构的改变将有助于了解干眼症的发病机制。 近年来细胞凋亡在免疫性疾病中的作用逐渐受到重视。目前观点认为机体免疫功能过强是由于淋巴细胞凋亡减少所致。细胞凋亡在干眼症发病机制中的作用主要包括两方面：一是对泪腺和结膜杯状细胞影响，一是对炎症细胞(淋巴细胞)的影响。研究干眼症眼表面凋亡标志物(凋亡细胞及相关基因蛋白)的表达与干眼症病因之间的关系是研究干眼症发病机制的关键。 干眼症传统治疗是治标治疗，常采用泪液替代和维持泪液在眼内存留时间的方法，没有对病因治疗。近年来随着对干眼症研究的进展，出现了一些新的治疗方法。中文摘要根据干眼症的病因进行对因治疗，不仅可加深对干眼症发病机制的认识，还为临床治疗干眼病提供理论依据。 为了探讨干眼症发病机制及治疗的重要问题，我们对干眼症进行了四个方面的研究。第一部分干眼症动物模型的建立及眼表损害诊断 目的:建立干眼症动物模型并进行眼表损害的诊断。 材料与方法:分别制作维生素A缺乏兔干眼症模型9只及去势雄兔干眼症模型9只。前者于实验前和实验后2、3、4、5、6个月行Schirmer试验、泪膜破裂时间检测及虎红染色检测:后者于实验前和实验后2、3、4周、2及3个月行上述检查。 结果:维生素A缺乏兔实验后4个月起、去势干眼症兔实验后3周起Schirmer试验、泪膜破裂时间明显小于实验前，且随观察时间的延长差异有显著性(尸叱0.01)。虎红染色实验后为阳性，试验前为阴性。 结论:维生素A缺乏模型兔及去势雄性模型兔泪液分泌减少、泪膜稳定性下降、角膜表面染色，可诊断为干眼症。维生素A缺乏及雄激素水平降低均可导致干眼症发生。第二部分干眼症模型兔泪腺、角膜及结膜的组织病理和超微结构的研究 目的:观察干眼症模型兔泪腺、角膜及结膜组织病理和超微结构的改变与眼表干变的关系。 材料与方法:分别取3只维生素A缺乏干眼症兔、3只去势干眼症雄兔及3只正常对照兔双眼泪腺、角膜及结膜组织，部分标本常规石蜡包埋，行苏木素一伊红染色，光学显微镜观察;部分标本行透射电镜和扫描电镜观察。 结果:维生素A缺乏干眼症兔泪腺组织灶性淋巴细胞浸润增值、腺体萎缩;角膜上皮呈多层、上皮细胞形态不规则、上皮结膜化、细胞坏死脱落;结膜杯状细胞消失、淋巴细胞浸润。超微结构见泪腺内质网破坏、线粒体呈空泡样;角膜表层上皮微绒毛肿胀脱落、桥粒解体。 去势干眼症雄兔泪腺上皮细胞小而密、腺腔扩大;角膜上皮呈多层、排列不规则;结膜杯状细胞消失。超微结构见泪腺内质网减少、线粒体呈空泡样变;角膜表层上皮微绒毛融合脱落、桥粒解体。 结论:维生素A缺乏及雄激素缺乏干眼症模型兔泪腺、角膜及结膜组织病理和中文摘要超微结构较正常兔均有明显异常，这些改变可导致模型兔泪腺分泌减少、泪膜稳定性下降、角膜及结膜上皮干躁。第三部分干眼症模型兔泪腺、角膜及结膜上皮细胞凋亡、 相关基因及雄激素受体表达的研究 目的:探讨干眼症模型兔泪腺、角膜及结膜上皮细胞凋亡、相关基因及雄激素受体表达与组织损伤的关系。 材料与方法:分别取3只维生素A缺乏干眼症兔、3只去势干眼症雄兔及3只正常对照兔双眼泪腺、角膜及结膜组织，采用原位末端标记及免疫组织化学方法，对各组织上皮细胞中的凋亡细胞及Fas、FasL、Bax和bel一2等相关基因蛋白的表达进行检测;采用免疫组织化学方法对去势及正常雄兔泪腺、角膜及结膜中雄激素受体进行?更多还原

【Abstract】 Xerophthalmia, which is also called dry syndrome, from whatever cause is a significant cause of blindness not only because the precomeal tear film is essential for corneal transparency but also because the dry eye develops keratitis with ulceration and opacification. Henrik SjOgren first brought forward the concept of dry syndrome in 1933. The modem definition was advanced by Brewitt in 1995, which said that xerophthalmia resulted from lacrimal dysfunction and insufficiency, was one of the most popular ophthalmological disease which could progress to keratomalacia and led to blindness, was a human disease characterized by the loss of globlet cells from the conjunctival epithelium and keratinization of the corneal epithelium. Recent research found that xerophthalmia was caused by vitamin A deficiency, inflammation, immunity, apoptosis, sex hormone level and so on. But the pathogenesis of xerophthalmia is still under discussing. Especially in China, there is still a lot to be researched on the pathogenesis and therapy of xerophthalmia.Animal model is a kind of important carrier to develop clinical and basic research. Successfully establishing the animal models with xerophthalmia according to the assumed causes is the foundation to give more study on the disease. Patients with xerophthalmia are characterized by tear secretion decrease, precomeal tear film instability, thin thickness of cornea, corneal surface irregularity and so on. To diagnose the animal models as xerophthalmia can offer some proof on clinical diagnosis.The pathological changes of xerophthalmia are characterized by lymphocyte soakage in lacrimal glands, cornea ulceration, keratinization of the corneal epithelium, loss of globlet cells from the conjunctival epithelium and so on. The ultrastructural changes of xerophthalmia are endoplast breakage and mitochondria swelling in lacrimal glands, microvilli desquamation on the corneal superficial epithelial cells and so on. All these changes are due to tear deficiency and will aggravate tear deficiency. To study the pathological and ultrastructural changes of xerophthalmia will be helpful to realize the pathogenesis of it.Recent research found that apoptosis played an important role in autoimmunity disease. Views suggested that excessively strong immunoreaction was caused by the decreasement of the apoptotic lymphocyte. Apoptosis plays an important role in xerophthalmia in two sides: one is to inhibit the lacrimal glands and the conjunctival globlet cells, the other is to influence the inflammatory cells. To study the relation between apoptosis andxerophthalmia is the key to realize the pathogenesis of xerophthalmia.The traditional treatment of xerophthalmia is to take temporary solution, such as topicalapplication of tear substitute and keeping tears from evaporation. Recent research focusesin effecting a permanent cure. To treat xerophthalmia according to the causation can notonly help to realize the pathogenesis of it but also afford academic evidence for clinicaltreatment.To investigate the pathogenesis and therapy of xerophthalmia, we study the disease infour aspects.Part I The Establishment and Diagnosis of Xerophthalmia ModelsObjective: To establish and diagnose animal models with xerophthalmia.Material and Methods: 9 rabbits were given a casein-base vitamin A-deficient diet forsix months and we got xerophthalmia models. Schirmer’s test, tear film break-up time(BUT), rose bangle (rb) staining and corneal thickness were performed on the eyes at 2%3> 4> 5% 6 months after and before the experiment. 9 male rabbits were castrated and after3 months we got xerophthalmia models. The aforesaid examinations were performed onthe eyes at 2 > 3 > 4 weeks, 2 and 3 months after and before the experiment.Results: Schirmer’s test, tear film break-up time and corneal thickness were significantlylower in both groups after the experiment. The difference became more and moreprominent in the course of observation. Rose bangle staining was positive更多还原