Effects of edible bird's nest (EBN) on cultured rabbit corneal keratocytes

Fadhilah Zainal Abidin,Ng Sook Luan,Chua Kien Hui,Elvy Suhana Mohd Ramli,Lee Ting Hun,Norzana Abd Ghafar

doi:10.1186/1472-6882-11-94

Abstract

BackgroundThere has been no effective treatment or agent that is available for corneal injury in promoting corneal wound healing. Previous studies on edible bird's nest extract (EBN) had reported the presence of hormone-like substance; avian epidermal growth factor that could stimulate cell division and enhance regeneration. This study aimed to investigate the effects of EBN on corneal keratocytes proliferative capacity and phenotypical changes.MethodsCorneal keratocytes from six New Zealand White Rabbits were isolated and cultured until Passage 1. The proliferative effects of EBN on corneal keratocytes were determined by MTT assay in serum-containing medium (FDS) and serum-free medium (FD). Keratocytes phenotypical changes were morphologically assessed and gene expression of aldehyde dehydrogenase (ALDH), collagen type 1 and lumican were determined through RT-PCR.ResultsThe highest cell proliferation was observed when both media were supplemented with 0.05% and 0.1% EBN. Cell proliferation was also consistently higher in FDS compared to FD. Both phase contrast micrographs and gene expression analysis confirmed the corneal keratocytes retained their phenotypes with the addition of EBN.ConclusionsThese results suggested that low concentration of EBN could synergistically induce cell proliferation, especially in serum-containing medium. This could be a novel breakthrough as both cell proliferation and functional maintenance are important during corneal wound healing. The in vitro test is considered as a crucial first step for nutri-pharmaceutical formation of EBN-based eye drops before in vivo application.

Highlights

There has been no effective treatment or agent that is available for corneal injury in promoting corneal wound healing
Cell Viability and Proliferative Assay The corneal keratocytes cultured in FDS showed higher proliferative potential at 0.05% EBN (p = 0.003) and 0.1% EBN (p = 0.03) [Figure 1A] compared to the FDS alone
This suggested nutrient depreciation from the medium by EBN that leads to a marked reduction in corneal keratocytes proliferation

Summary

Introduction

There has been no effective treatment or agent that is available for corneal injury in promoting corneal wound healing. Topical agents available in the market for treating corneal wounds and ulcers inhibit the healing process because of the presence of preservatives such as benzalkonium chloride (BAK) and polyquartenium-1. These preservatives were used to prevent bacterial contamination and were usually found in multidose preparations [14]. A study by Collin (1986) revealed that BAK should not be used on corneas with abnormal epithelium as it could cause extensive damage involving the mitochondria, other organelles and the outer cell membrane of the corneal stromal cells [15]

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