The anti-scarring role of Lycium barbarum polysaccharide on cornea epithelial-stromal injury

Abstract

Purpose: Cornea epithelial-stromal scarring is related to the differentiation of fibroblasts into opaque myofibroblasts. Our study aims to assess the effectiveness of Lycium barbarum polysaccharide (LBP) solution as a pre-treatment in minimizing corneal scarring.

Methods: Human corneal fibroblasts were cultured in a three-dimensional collagen type I-based hydrogel in an eye-on-a-chip model. Fibroblasts were pre-treated with 2 mg/mL LBP for 24 h, followed by another 24-h incubation with 10 ng/mL transforming growth factor-beta 1 (TGF-β1) to induce relevant physiological events after stromal injury. Intracellular pro-fibrotic proteins, extracellular matrix proteins, and pro-inflammatory cytokines that involved in fibrosis, were assessed using immunocytochemistry and enzyme-linked immunosorbent assays.

Results: Compared to the positive control TGF-β1 group, LBP pre-treated cells had a significantly lower expression of alpha-smooth muscle actin, marker of myofibroblasts, vimentin (p < 0.05), and also extracellular matrix proteins both collagen type II and type III (p < 0.05) that can be found in scar tissues. Moreover, LBP pre-treated cells had a significantly lower secretion of pro-inflammatory cytokines interleukin-6 and interleukin-8 (p < 0.05). The cell-laden hydrogel contraction and stiffness showed no significant difference between LBP pre-treatment and control groups. Fibroblasts pretreated with LBP as well had reduced angiogenic factors expression and suppression of undesired proliferation (p < 0.05).

Conclusion: Our results showed that LBP reduced both pro-fibrotic proteins and pro-inflammatory cytokines on corneal injury in vitro. We suggest that LBP, as a natural Traditional Chinese Medicine, may potentially be a novel topical pre-treatment option prior to corneal refractive surgeries with an improved prognosis.