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JingHua Bu, JINGWEN YU, Yang Wu, Xin He, Hui He, Zuguo Liu, Wei Li; Hyperlipidemia disrupts corneal endothelium. Invest. Ophthalmol. Vis. Sci. 2019;60(9):2152.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate the pathological changes of corneal endothelium and related mechanism in hyperlipidemic murine models.
Hyperlipidemic murine model was generated by feeding 4-week-old male wild type (WT) and Apolipoprotein E knockout (ApoE-/-) mice with high fat diet (HFD). Control group was fed with standard diet (SD). Body mass and cholesterol levels were quantified after 16 weeks. Corneal endothelium density was evaluated by in vivo confocal microscopy. Corneal endothelial tissue sections were subjected to scanning electron microscopy, transmission electron microscopy, and immunostaining for ZO-1, N-cadherin, Na-K+-ATPase, 4-HNE, 8-OHdG and NOX4. The gene expression of ZO-1, N-cadherin and Na+-K+-ATPase in corneal endothelium were evaluated by qRT-PCR. Corneal whole-mount tissues were subjected to ORO staining to demonstrate lipid deposition. Corneal endothelium damage model was used to observe the corneal endothelium function after injuring. Aqueous humor was extracted and subjected to mass spectrometric identification. Primary cultures of rabbit corneal endothelial cells (rCECs) were treated with varying concentrations of palmitate. After 24h of palmitate treatment, CCK8 viability assay and immunostaining for ZO-1, N-cadherin, Na+-K+-ATPase, TOM20, TIM23 and PPAR-γ were performed. The gene expression of ZO-1, N-cadherin, Na+-K+-ATPase, NOX4, Nrf2, SOD1, CAT, GPX1 and PPAR-γ were evaluated by qRT-PCR. To further detect the mechanisms involved, the palmitate-treated rCECs were cultured with or without rosiglitazone, and the gene expression of ZO-1, N-cadherin, Na+-K+-ATPase, PPAR-γ were evaluated by qRT-PCR.
Hyperlipidemia was induced in both WT mice fed with HFD and ApoE-/- mice fed with SD or HFD mice. ORO staining showed accumulation of lipid droplets in CECs of hyperlipidemic mice. Reduced CECs density, decreased corneal edema recovery ability, cell junction disruptions, functional marker downregulation, activation of oxidative stress and changes in mitochondrial ultra-structures were observed in CECs of hyperlipidemic mice. Palmitate levels in aqueous humor significantly increased in hyperlipidemia mice. Dose-dependent cytotoxicity of palmitate, disrupted cell morphology and function were observed in vitro hyperlipemia model and the effect was reversed by rosiglitazone treatment.
Hyperlipidemia induced oxidative stress and down-regulation of PPAR-γ in CECs, ultimately leading to pathological changes in CECs.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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