Dry Eye Induced By Destroying The Morphology Of Corneal Epithelial Cell Microvilli Through Abnormal Lipid Metabolism In Sleep Deficient Mice

Objective:To investigate the mechanism of mice model of dry eye induced by sleep deficiency in under physiological conditions.Methods:18 to 20g adult C57BL/6 mice were used to establish sleep deficiency(SD)model of mice by using sticks over water.Mice were randomly divided into five groups:Normal control group(Normal group),SD 5D group,SD 10D group,fenofibrate treated group(Feno group)and 0.1%DMSO treated group(DMSO group).Feno and DMSO group at the sixth day of modeling were treated respectively with 10?L 200?M fenofibrate and 0.1%DMSO eye drops three times a day.SD 5D group mice were tested for clinical indexes of dry eye,which including Schirmer's test,OGD staining and PAS staining on the fifth day and the other group were tested on the tenth day.At the same time,cornea was preparated of extracting from RNA and protein,frozen and paraffin sections and scanning electron microscope samples.Immunohistochemistry,quantitative real-time PCR(qRT-PCR)and western blot(WB)were used to detect the expression of PPARa,lipid metabolism.enzymes,and TRPV6;hematoxylin and eosin(HE)staining was used to detect the change of cornea,lacrimal gland and Meibomian gland;scanning electron microscope(SEM)was used to detect the microvilli of corneal epithelial cells;Oil Red O staining was used to detect the accumulation of lipid in cornea and merbomian gland.The effects of PPARa deficiency on the above indexes were cornfirmed by PPAR?-/-mice.Fenofibrate treatment of primary cultured corneal epithelial cells was used to detect the influence of increased PPARa of the expression of TRPV6.Results:Compared with normal control group,tear secretion and OGD staining of SD group mice continued to increase with prolonging the molding time;the lipid metabolism disorder of cornea was manifested by the decreased of lipid metabolism enzymes and the accumulation of corneal lipids;the expression of PPARa and TRPV6 decreased,the density of corneal epithelial cell microvilli reduced and microvilli showed abnormal shape;the meibomian gland showed no abnormalities,but the lacrimal gland hypertrophy and conjunctival goblet cells increased.The results of PPAR?-/-mice were consistent with those of SD group mice.Topical application of fenofibrate can significantly improve corneal lipid metabolism by promoting the expression of PPARa on SD group mice,and then promoted the expression of TRPV6 and the formation of corneal epithelial cell microvilli.The results of the fenofibrate treated primary cultured corneal epithelial cells also confirmed that fenofibrate can upregulate the expression of TRPV6 by promoting the expression of PPARa.Conclusion:Under physiological conditions,sleep deficiency can not damage the function of the lacrimal gland,goblet cells and meibomian gland,but inhibited expression of PPARa of corneal epithelial cells,resulted in down-regulated expression of TRPV6 and abnormal lipid metabolism,and then destroyed the morphology of corneal epithelial cell microvilli induced dry eye.