Mucoadhesive Bletilla striata Polysaccharide-Based Artificial Tears to Relieve Symptoms and Inflammation in Rabbit with Dry Eyes Syndrome.

Minal Thacker,Ching-Li Tseng,Feng-Huei Lin,Chih-Yen Chang,Hsuan Yu Chen,Subhaini Jakfar

doi:10.3390/polym12071465

Abstract

Dry eye syndrome (DES) is a multifactorial disorder of the ocular surface affecting many people all over the world. However, there have been many therapeutic advancements for the treatment of DES, substantial long-term treatment remains a challenge. Natural plant-based polysaccharides have gained much importance in the field of tissue engineering for their excellent biocompatibility and unique physical properties. In this study, polysaccharides from a Chinese ground orchid, Bletilla striata, were successfully extracted and incorporated into the artificial tears for DES treatment due to its anti-inflammatory and mucoadhesive properties. The examination for physical properties such as refractive index, pH, viscosity and osmolality of the Bletilla striata polysaccharide (BSP) artificial tears fabricated in this study showed that it was in close association with that of the natural human tears. The reactive oxygen species (ROS) level and inflammatory gene expression tested in human corneal epithelium cells (HCECs) indicated that the low BSP concentrations (0.01–0.1% v/v) could effectively reduce inflammatory cytokines (TNF, IL8) and ROS levels in HCECs, respectively. Longer retention of the BSP-formulated artificial tears on the ocular surface is due to the mucoadhesive nature of BSP allowing lasting lubrication. Additionally, a rabbit’s DES model was created to evaluate the effect of BSP for treating dry eye. Schirmer test results exhibited the effectiveness of 0.1% (v/v) BSP-containing artificial tears in enhancing the tear volume in DES rabbits. This work combines the effectiveness of artificial tears and anti-inflammatory herb extract (BSP) to moisturize ocular surface and to relieve the inflammatory condition in DES rabbit, which further shows great potential of BSP in treating ocular surface diseases like DES in clinics in the future.

Highlights

Dry eye syndrome (DES) is one of the most prevalent ocular surface diseases in the worldwide affecting 8% to 14% of the population [1,2]
The classification of dry eyes can be categorized into two major subtypes: aqueous deficient dry eye (ADDE), a condition where the lacrimal tear secretion is reduced and hyper evaporative dry eye (EDE), wherein the evaporation of the tear film is uncontrollable with regular lacrimal tear secretion [9,10]
Dichlorofluorescin diacetate (DCFDA) kit was obtained from Abcam Company (Eugene, OR, USA). keratinocyte-serum free medium (KSFM), bovine pituitary extract (BPE), insulin, trypsin-ethylenediaminetetraacetic acid (EDTA), penicillin/streptomycin and phosphate-buffered saline were obtained from Gibco BRL

Summary

Introduction

Dry eye syndrome (DES) is one of the most prevalent ocular surface diseases in the worldwide affecting 8% to 14% of the population [1,2]. The classification of dry eyes can be categorized into two major subtypes: aqueous deficient dry eye (ADDE), a condition where the lacrimal tear secretion is reduced and hyper evaporative dry eye (EDE), wherein the evaporation of the tear film is uncontrollable with regular lacrimal tear secretion [9,10]. Both these conditions could result in tear hyperosmolarity, which is an important intermediary in causing DES related inflammation. Inflammation and dryness other symptoms of DES include pain, discomfort, visual hinderance, redness, burning sensation and sensitivity towards light [5]

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