κ-Carrageenan from Grateloupia filicina protects against PM_2.5-induced intraocular pressure elevation

This study investigates the efficacy of GFP01, an almost pure κ-carrageenan derived from Grateloupia filicina, in counteracting intraocular pressure (IOP) elevation induced by PM_2.5 exposure. GFP01, characterized by a molecular weight of 97.8 kDa, exhibits a linear backbone composed of 4-O-sulfated-β-D-galactose and 3,6-anhydro-α-D-galactose. In a murine model subjected to PM_2.5-induced high IOP, GFP01 treatment significantly mitigated IOP compared to the PM_2.5 group (n = 12, p < 0.01). In vitro assays revealed a 27.7 % increase in cell viability in human trabecular meshwork cells (HTMCs) treated with GFP01 compared to controls exposed to PM2.5 (p < 0.001, n = 5 cell lines). Additionally, GFP01 decreased PM_2.5-induced transendothelial electrical resistance (TEER) of angular aqueous plexus (AAP) cells by 35.8 % at 48 h post-treatment (p < 0.05, n = 3 cell lines). Western blot analysis further demonstrated GFP01's role in inhibiting NLRP3/caspase-1/GSDMD/IL-1β axis in ocular tissues and HTMCs. Cytotoxicity assessment and slit-lamp imaging confirmed the safety of GFP01. In conclusion, GFP01 demonstrates a significant protective effect against PM_2.5-induced IOP elevation, making it a promising therapeutic candidate for clinical applications.