Exploring the therapeutic potential: sinomenine and melatonin in alkali-induced corneal burns

This study aimed to investigate the effects of sinomenine and melatonin on corneal alkali burns.

Twenty-seven female Wistar albino rats, aged 3–6 months and weighing 200–300 g, were used in this study. After the induction of general anesthesia, 2 mol/L sodium hydroxide (NaOH) solution was used to create corneal alkali burns in all experimental animals. The rats were divided into three groups: Group C, control group with no additional treatment; Group M, topical melatonin drop group; and Group S, topical sinomenine group. The rats were sacrificed under general anesthesia on the 7th day. Various parameters, including corneal inflammation, neovascularization, epithelialization, epithelial proliferating cell nuclear antigen (PCNA), epithelial inducible nitric oxide synthase (INOS), stromal INOS, and thickness, were evaluated.

The experiment was completed with 27 rats distributed into three groups of nine rats each. Significant differences were observed between the groups in terms of stromal thickness, inflammation, epithelial iNOS, stromal iNOS, and epithelialization (p = 0.008, p = 0.005, p = 0.020, p = 0.037, and p = 0.000, respectively). The best stromal thickness was observed in Group M. Vascularization, inflammation, epithelial INOS, stromal iNOS, and epithelialization were most effectively reduced in Group S, followed by Group M. Group S outperformed Group C significantly in all these aspects (p = 0.049, p = 0.004, p = 0.015, p = 0.036, p = 0.000, respectively). There was no significant difference between the groups in terms of the epithelial PCNA levels (p = 0.259).

The results suggest that topical sinomenine and melatonin have anti-inflammatory, anti-angiogenic, and reepithelialization effects when applied after alkali burns in rat corneas.