The Protective Effect of Polygonum cuspidatum (PCE) Aqueous Extract in a Dry Eye Model

Abstract

Dry eyes are caused by highly increased osmolarity of tear film, inflammation, and apoptosis of the ocular surface. In this study, we investigated the effect of Polygonum cuspidatum (PCE) aqueous extract in in vivo and in vitro dry eye models. Dry eye was induced by excision of the lacrimal gland and hyperosmotic media. In vivo, oral administration of PCE in exorbital lacrimal gland-excised rats recovered tear volume and Mucin4 (MUC4) expression by inhibiting corneal irregularity and expression of inflammatory cytokines. In vitro, hyperosmotic media induced human corneal epithelial cell (HCEC) cytotoxicity though increased inflammation, apoptosis, and oxidative stress. PCE treatment significantly inhibited expression of cyclooxygenase-2 and inflammatory cytokines (interleukin-6 and tumor necrosis factor-α), and activation of NF-κB p65 in hyperosmolar stress-induced HCECs. Hyperosmolarity-induced increase in Bcl-2-associated X protein (BAX) expression and activation of cleaved poly (ADP-ribose) polymerase and caspase 3 were attenuated in a concentration-dependent manner by PCE. PCE treatment restored anti-oxidative proteins such as heme oxygenase-1 (HO-1), superoxide dismutase-1 (SOD-1), and glutathione peroxidase (GPx) in hyperosmolar stress-induced HCECs. These data demonstrate that PCE prevents adverse changes in the ocular surface and tear fluid through inhibition of hyperosmolar stress-induced inflammation, apoptosis, and oxidation, suggesting that PCE may have the potential to preserve eye health.

Apricot Kernel Extract and Amygdalin Inhibit Urban Particulate Matter-Induced Keratoconjunctivitis Sicca

“…The corneal epithelial damage and irregularity are affected by MMPs released from the ocular surface, including the corneal and conjunctival epithelium [23]. Among MMPs, MMP-9 has a critical role in disrupting the epithelial barrier function [24,25]. In this study, our results show that mRNA expression and activity of MMP-9 were elevated in the conjunctival epithelium with UPM exposure; these were inhibited by AKE and amygdalin.…”

Cluster Analysis of Dry Eye Disease Models Based on Immune Cell Parameters – New Insight Into Therapeutic Perspective

“…Another study used 1% atropine sulfate to instill into the eyes three times a day for 3 days ( 54 ). For Wister rats, Joossen et al, and Park et al, induced dry eye by removing the lacrimal gland ( 55 , 56 ). Ru et al, induced dry eye by injecting scopolamine hydrobromide ( 57 ).…”

Achyranthis radix Extract-Loaded Eye Drop Formulation Development and Novel Evaluation Method for Dry Eye Treatment

“…Inhibitory effect of formulations on hyperosmotic stress-induced inflammation was assessed with modification of a previously described method [21]. The cells were co-treated with the indicated concentration of formulations and hyperosmolar cell culture media (528 mOsM) for 24 h. Total RNA was extracted using TRIZOL, and the yield and purity of RNA were conducted by the measurement of ratio of the absorbance at 260 and 280 nm.…”

“…Because the USL solution had a yellowish color, there was a possibility of pigmentation in the cornea when it was used as eye drops. A new method was developed to identify the possibility of pigmentation with a little modification [21,23]. The egg shell inner membrane could be used as a protein membrane to simply confirm the pigmentation.…”