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BACKGROUND:In recent years,increasing studies have focused on the abnormal proliferation and differentiation of acinous cells in the meibomian gland,suggesting that this process is closely related to the occurrence and development of dry eye.Structural and functional abnormalities such as blockage of the lumen of the meibomian gland and atrophy of the glands can cause or exacerbate dry eye.Therefore,the study of changes in the meibomian glands in dry eyes is important for understanding the pathogenesis of dry eyes in depth and finding new targets for the treatment and prevention of dry eyes. OBJECTIVE:To investigate the changes of the meibomian gland in a mouse model of aqueous deficient dry eyes. METHODS:Thirty-two female C57/B6 mice at 6-8 weeks were selected and randomly divided into experimental and control groups with 16 mice in each group.The mice in the experimental group were constructed by removing both the extra-orbital and intra-orbital lacrimal glands,while those in the control group were not treated.After 2 weeks of normal feeding,the corneal changes of both groups were observed under a slit lamp,and the tear secretion of both groups was measured.The meibomian glands of the two groups of mice were removed after decapitation.The changes in the gross morphology of the meibomian glands were observed and the meibomian glands were made into frozen sections.Hematoxylin-eosin staining was used to observe the structure of the meibomian glands,oil red staining was used to evaluate the function of the meibomian glands,and immunofluorescence staining and RT-qPCR were used to observe the expression of cytokeratin 14,Ki67 and abnormally differentiated small proline-rich protein 1B in the meibomian glands of mice. RESULTS AND CONCLUSION:Two weeks after modeling,lamellar defects were seen in the corneas of the experimental mice,and neovascularization of the limbal corneal was generated and invaded the central cornea.(2)Tear secretion volume was significantly reduced in the experimental group compared with the control group(P<0.05).Microscopic findings showed that the ducts of the meibomian glands in the experimental group were interrupted and atrophied,and their arrangement was disorganized.Hematoxylin-eosin staining results showed a significant increase in lipid vacuoles in the meibomian glands of the experimental mice compared with the control group.Lipid deposition was seen in oil red staining in the experimental group.Immunofluorescence and RT-qPCR results showed a significant increase in the expression of cytokeratin 14,Ki67 and small proline-rich protein 1B in the meibomian glands of mice in the experimental group compared with the control group(P<0.05).To conclude,aqueous deficient dry eye can lead to compensatory hypertrophy,increased proliferation,and abnormal lipid metabolism in the meibomian gland,as well as abnormal differentiation of the meibomian gland.
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Objective To construct engineered corneal epithelium from embryonic stem cells (ESCs) using Rock inhibitor combined with hypoxia-normoxia culture condition. Methods Human ESC line H1 was induced to differentiate into epithelial-like cells by addition of retinoic acid (RA) and bone morphogenetic protein 4(BMP4) in the differentiation medium under the adherent culture condition. The ESCs derived epithelial-like cells were expanded in the mixed medium of SHEM and KSFM with the mixture ratio of 1 : 2 with or without Rock inhibitor Y27632. The H1 derived epithelial-like cells were seeded on the denuded ammonic membrane to construct engineered corneal epithelium under hypoxia,normoxia and hypoxia-normoxia culture conditions,respectively. The inducted effect of ESCs into epithelial-like cells,the expansion ability of the epithelial-like cells and the characteristics of the constructed engineered corneal epithelium were evaluated by morphological observation, real-time fluorescent quantitative polymerase chain reaction (RTFQ-PCR) and immunofluorescence technology. Results Compared with the control group,the relative expressions of ESCs marker Oct4 mRNA, Notch signaling pathway related factors Notch1 and Jagged1 mRNA,and Wnt signaling pathways related factors c-myc and Cyclin D1 mRNA were significantly reduced, and the relative expressions of cutaneous ectoderm markers p63 and K18 mRNA were significantly increased at day 8 after induction in the induced group,with significant differences between them (t =14.63,20.15,93.50,11.60, 19.30,18.44,22.63;all at P<0.05). Compared with the without Y27632 group,the relative expressions of p63 and K14 mRNA,Notch signal pathway receptor Notch1 and Jagged1 mRNA were significantly increased,and Wnt signaling pathways downstream targeted gene c-myc and CylinD1 mRNA were significantly decreased at day 8 after induction in the Y27632 group,with significant differences between them (t =20.29,59.22,2.90,39.59,5.32,10.14;all at P<0.05),and the relative expression of K18 mRNA in the two groups was not significantly changed(t=1.38,P>0.05). The ESCs derived epithelium and constructed under hypoxia-normoxia culture condition showed more obvious stratification and tighter cell arrangement in comparison with those cells cultured in consistent hypoxia culture condition or normoxia culture condition. Epithelial markers Pan-CK and K18 as well as epithelial progenitor cell markers p63 and K14 expressed in the whole cell layers of the ESCs derived epithelium constructed under hypoxia-normoxia culture condition. Conclusions The addition of Y27632 enhances the proliferation ability of H1 derived epithelial cells and actives Notch signaling pathway and inhibits Wnt signaling pathway. The culture and construction in the expansion medium with Y27632 under the hypoxia-normoxia culture condition can promote the stratification of H1 derived engineered corneal epithelium.