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Anita K. Ghosh, Rubina Thapa, Harsh Nilesh Hariani, Agne Ziniauskaite, Samatha Ankireddy, Karoline A Orloff, Jenni J. Hakkarainen, Giedrius Kalesnykas, Kelly Langert, Simon Kaja; Xanthohumol protects corneal epithelial cells in experimental models for dry-eye disease. Invest. Ophthalmol. Vis. Sci. 2020;61(7):3257.
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© ARVO (1962-2015); The Authors (2016-present)
Xanthohumol (Xn) is a naturally occurring antioxidant found in the hops plant (Humulus lupulus). The purpose of this study was to determine the cytoprotective effects of Xn in experimental models for dry eye disease (DED) in vitro and in vivo.
Human Corneal Epithelial cells (HCET; Riken; Japan) were treated with concentrations from 1 μM to 5 μM Xn and subsequently exposed to chemically-induced oxidative stress using tert-butyl hydroperoxide (tBHP) for 6 hr. Lactate dehydrogenase (LDH) release and 3(4,5dimethylthiazol2yl) 2,5diphenyltetrazolium bromide (MTT) uptake assays were used to determine the cytoprotective effects of Xn. Immunoblotting was used to quantify expression of phase II antioxidant enzymes. Male C57BL/6J mice were exposed to desiccating stress combined with transdermally administered scopolamine for a period of 26 days. Mice were treated once daily with either empty or Xn-encapsulating poly(lactic-co-glycolic acid) (PLGA, 85/15%) nanoparticles (NP) from days 15 to 26. Corneal fluorescein staining was used as primary readout to determine in vivo efficacy. Ophthalmic cyclosporine (0.05%; formulated as Restasis®, Allergan plc., Irvine, CA) was administered twice daily and used as positive control for the assay.
Xn exerted a statistically significant dose-dependent protection of HCE-T cells against tBHP-induced oxidative stress. The EC of tBHP shifted from 15.2 ± 0.5 μM (untreated, n = 4) to 33.3 ± 3.4 μM (5 μM, n = 4, P < 0.01) in the MTT assay and, similarly, in the LDH assay (13.4 ± 0.4 μM vs.100.0 ± 11.7 μM; n = 4; P < 0.01). Xn (5 μM) elicited a transient increase in Nrf2 expression that peaked 6 h after Xn treatment (4.46-fold over baseline; mixed-effects analysis with Holm Sidak multiple comparisons test, P<0.01). In vivo, desiccating stress resulted in significant corneal damage as assessed by corneal fluorescein staining. Treatment with Xn-encapsulating PLGA NPs resulted in a statistically significant reduction of corneal fluorescein staining from day 15 to day 26 (P < 0.05), while empty NPs had no effect (P = 0.25). Xn had no effects on tear volume (P = 0.35).
Xn exerts cytoprotective effects against oxidative stress in human corneal epithelial cells and can improve corneal surface damage from desiccating stress/ scopolamine administration. PLGA NP represent a safe and efficacious formulation for hydrophobic compounds.
This is a 2020 ARVO Annual Meeting abstract.
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