Abstract
Purpose :
1) To evaluate the effectiveness of Lycium barbarum polysaccharide (LBP) in promoting corneal repair after alkaline injury.
2) To evaluate the role of LBP in suppressing the secretion of pro-inflammatory cytokines in the corneal epithelium.
Methods :
The corneas of C57BL/6J mice were pre-treated with topical phosphate-buffered saline or LBP (0.2/ 2/ 20 mg/mL) for 7 days 4 times per day, followed by 0.1M sodium hydroxide injury for 30 seconds and washing with distilled water for another 30 seconds. Area of epithelial defect and thickness of the cornea were evaluated using sodium fluorescein staining and hematoxylin and eosin stain. The proportion of apoptotic cells was assessed by TUNEL assay. Inflammatory cytokines, including interleukin-1 beta (IL-1β), matrix metalloproteinase 12 (MMP12), and platelet-derived growth factor-B (PDGF-BB) levels were assessed using immunohistochemistry and Western blot.
Results :
0.2, 2, 20 mg/mL LBP topical solution induced no significant apoptosis to the corneal cells. No significant difference in the total corneal, epithelium and stromal thickness was found between control and LBP pre-treated groups. Compared to the injury group, mice with 2 mg/mL LBP pre-treatment revealed a significant decrease in the fluorescein-stained area upon injury (p=0.025), with increased epithelial layer thickness (p=0.004). The corneal opacity was significantly reduced in the group with 2 mg/mL LBP pre-treatment followed by injury (p=0.02). The expression of matrix metalloproteinase 12 (p=0.033) and platelet derived growth factor-BB (p=0.03) resulted in a decrease in expression level in group with 2 mg/mL LBP pre-treatment compared to the injury group.
Conclusions :
The study presented the efficacy of topical 2 mg/mL LBP pre-treatment, with a safety profile, in promoting corneal epithelial wound healing. We have also demonstrated the promising therapeutic effect of LBP in promoting the restoration of corneal transparency after injury, which is attributable to its anti-inflammatory effect. Our findings suggest that LBP may be considered as a potential preventative method against the formation of chemical-induced cornea defects, particularly those related to alkali burn injury.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.