The Study On Pathogenesis Of Xerophthalmia In Experimental Estrogen-Deficient Models

Objective: To establish a xerophthalmia model of estrogen-deficiency in rat. Furthermore, to study the expression of Apoptosis, relative genes and estrogen receptor(ER) in epithelial cells of corneas, conunctivas, meibomian glands and lacrimal gland of xerophthalmia model and the relationship to tissue damage.Method: 20 female rats were divided into 2 groups randomly, 10 rats every group. We made Schirmer test, tear film break-up time(BUT) and fluorescence staining on the eyes at 2weeks, 4weeks, 2months, 3months, 4months , 5months , 6months after and before the operation, and took 10 normal healthy Wister mouses as control group, we measured the ER lever after and before the operation in chemiluminescence. We execute all rats after 6 months. Small pieces of lacimal glands, corneas, conunctivas and meibomian glands of xerophthalmia models and normal controls were obtained. Parts of them were observed by microscope. Parts of them were observed by transmit electron microscope. Parts of them were investigated by immunohistochemical staining to detect the expression of Bax, bcl-2 and ER.Results: Schirmer test and tear film break-up time(BUT) were significantly lower in model group after operation for 5 months. The difference become more and more prominent in the course of observation ( P <0.05). Fluorescence staining was positive in model group after the experiment 4months . The ER lever after operation in blood serum were significantly lower than that of before operation (p<0.01) .The pathological changes of the xerophthalmia models were characterized by lymphocyte infiltration in lacrimal glands, lacrimal glands atrophy, comea ulceration, keratinization of the corneal epithelium, loss of globlet cells from the conjunctival epithelium and so on. The ultrastructural changes of xerophthalmia models were characterized by endoplast breakage and mitochondria swelling in lacrimal glands, microvilli desquamation on the corneal superficial epithelial cells and so on. Xerophthalmia models epithelial cells and meibomain cells showed obvious increased expression of Bax (P<0.01)and decreased expression of bcl-2(P<0.01) than normal controls . Estrogen receptor expressed in the nucleolus of the epithelium of lacrimal gland.Conclusion: The apoptosis of the epithelial cells in corneas, conjunctivas and meibomain cells may be one of the mechamisms leading to the destruction in...