Lycium Barbarum Polysaccharide Solution as a Novel Therapuetic Agent in the Prevention of Cornea Scarring

Abstract

Purpose: To compare effectiveness of lycium barbarum polysaccharide (LBP) solution with dexamethasone solution in the suppression of keratocyte myofibroblast-differentiation, fibrotic protein expression and extracellular matrix secretion in an in vitro model of cornea epithelial-stromal injury. Method: Primary human keratocytes (HK), of passage 3 to 6, were used for experiments. Myofibroblast differentiation and fibrotic protein expression- Cells were treated with 10ng/ml TGFB1 for 48 hours. Myofibroblast differentiation was assessed through α-smooth muscle actin immunofluorescence (IF) staining and quantified by Western blot. Type I collagen secretion was also examined and compared between groups via IF. Cell viability Assay - HKs were seeded onto 48-well plates, pre-treated with either 1) LBP solution of increasing concentrations or 2) Dexamethasone solution of increasing concentrations for 24 hours then TGFB1 induction at 10ng/ml for 48 hours. The number of viable cells was estimated using the MTS assay and compared between groups. Protein microarray for 11 inflammatory cytokines were performed on the culture media and compared between groups. Results: Both LBP (0.1 -3.0 mg/ml) and dexamethasone solutions significantly reduced TGFB1-induced myofibroblast differentiation of HK cell line and fibrotic protein expression (α-SMA and collagen type I) in a dose-dependent fashion. Furthermore, LBP significantly reduced myofibroblast cell viability but had no observable effect on undifferentiated HK cells. Conversely dexamethasone solution was shown to significantly reduce cell viablility of both myofibroblasts and HK cells. Protein microarray of culture media demonstrated that LBP suppressed TGFB1-induced IL-6 secretion, suggesting one possible mechanism in LBP’s observed effects in our model. Conclusion: LBP solution is a promising anti-fibrotic agent that selectively inhibits myofibroblast proliferation, fibrotic protein expression and extracellular matrix secretion while preserving keratocyte viability. Further work will be conducted to investigate the underlying mechanism involved.