The anti-scarring role of Lycium barbarum polysaccharride on cornea epithelial-stromal injury - an eye-on-a-chip study

Abstract

Purpose: The study is to assess whether Lycium barbarum polysaccharide (LBP) solution can be a novel therapy in modulating keratocytes differentiation after corneal epithelial- stromal injury in an eye-on-a-chip model. Setting: Stromal scarring of the cornea is the fourth common cause of global blindness, which contributes to 5.1% of the cases. The outcome of stromal scarring primarily depends on keratocytes differentiation. Under the action of transforming growth factor-beta 1, quiescent keratocytes will phenotypically differentiate into opaque myofibroblasts, leading to corneal haze. Methods: A 3D model made of PDMS elastomers is created to mimic the anatomy and physiology of the corneal stroma. The chip consists of a cell culture chamber and is connected to two channels where medium or LBP is supplied. Human keratocytes are suspended in collagen to form a three-dimensional hydrogel construct. Cells are pre-treated with 2 mg/mL LBP or 10-4M Dexamethasone for 24 hours, followed by 10 ng/mL TGF-1 for another 24 hours. Results: Cells pre-treated with LBP showed a decreased expression of alpha-smooth muscle actin, which is a prominent marker of myofibroblasts. Pro-fibrotic proteins such as vimentin, collagen II and collagen III are as well reduced. Cell-laden hydrogel pre-treated with LBP revealed no significant contraction compared to that in control group (p=0.29) while group pre-treated with TGF- showed increased contraction by 17.3% (p<0.001). The stiffness of the hydrogel treated with TGF-1 alone had an increase by 3.55-fold (p=0.02) yet that in the LBP group showed no significant difference compared to that in control group (p=0.9964) Conclusions: LBP can be a potential topical therapy to prevent corneal scarring prior to surgery. Optimized LBP concentration can potentially lead to fewer adverse effects compared to standard pharmacological treatments while minimizing keratocyte differentiation.