Green propolis with hyaluronic acid mitigates benzalkonium chloride-induced ocular surface injury in mice

Brazilian green propolis (GP) has antioxidant/anti-inflammatory activity and may protect the ocular surface from preservative toxicity. We tested a hyaluronic acid (HA)-based GP formulation in an acute benzalkonium chloride (BAK)-induced ocular surface injury model with dry eye disease (DED)-like features in BALB/c mice. Animals (n = 8/group; one eye treated) received 0.5% BAK (5 µL, 4×/day) for 5 days alone or concomitantly with 0.4% HA, HA + GP (0.5%), or HA + taurine (Tau; 0.5%). Tear production (Schirmer I; baseline, days 1, 3, 5) decreased in the BAK group by day 5 (p < 0.05 vs. baseline) but remained stable with HA + GP and HA + Tau. Corneal sensitivity was unchanged. HA + GP reduced clinical irritation/inflammation, preserved eyelid aperture, and maintained corneal smoothness. Corneal histology showed BAK-induced epithelial detachment and increased caspase-3 immunoreactivity, both similarly reduced by HA + GP and HA + Tau. Overall, HA + GP matched the HA + Tau benchmark and improved comfort-related measures.