Abstract:AIM: To investigate the effect of luteolin on tissue fibrosis in the filtering area following glaucoma trabeculectomy, and its relationship with the Wnt3a/β-catenin signaling pathway.
METHODS: Rabbits were selected to establish a fibrosis model after glaucoma trabeculectomy, and randomly divided into the sham operation group, model group, luteolin-L group and luteolin-H group. Dynamic monitoring of postoperative intraocular pressure was performed in all groups. Slit-lamp biomicroscopy was used to observe postoperative conjunctival morphological changes, conjunctival healing degree, corneal integrity, and anterior chamber inflammatory responses in the filtering bleb area. HE staining was performed to evaluate conjunctival epithelial integrity, subepithelial fibrous proliferation, and inflammatory cell infiltration in the filtering tissues. Masson's trichrome staining was applied to assess collagen deposition and the degree of tissue fibrosis. The expression of α-SMA was observed by immunohistochemical staining. The mRNA and protein expression levels of Wnt3a, Wnt7a, Wnt2b, β-catenin, LC3-I, LC3-II and p62-SQSTM1 in conjunctival tissues of the operative area were quantitatively detected by RT-
qPCR and Western blot, respectively.
RESULTS:Postoperative dynamic monitoring showed that the luteolin-H group achieved significantly better intraocular pressure control than the luteolin-L group compared with the model group(all P<0.05). Slit lamp observations confirmed that luteolin effectively ameliorated postoperative conjunctival injury, alleviated anterior chamber inflammatory response, and maintained the structural stability of the filtering area. HE and Masson staining revealed that luteolin intervention reduced conjunctival epithelial damage and inflammatory cell infiltration, markedly inhibited fibroblast proliferation, neovascularization and excessive collagen deposition, and significantly delayed the progression of filtering bleb scarring, with stronger effects in the luteolin-H group than luteolin-L group compared with the model group. Immunohistochemical staining demonstrated that luteolin intervention decreased the positive expression rate of α-SMA. Molecular assays indicated that the luteolin-H group had lower expression levels of Wnt3a, β-catenin and LC3-II/LC3-I, and the highest p62-SQSTM1 level in the operative site relative to the model group and luteolin-L group(all PSymbol|@@0.05). No significant intergroup differences were observed in Wnt2b and Wnt7a expression. These findings suggested that luteolin could specifically regulated the Wnt3a pathway and dose-dependently suppressed the activation of the Wnt3a/β-catenin pathway after glaucoma trabeculectomy, downregulated LC3-II/LC3-I expression, upregulated p62-SQSTM1 levels, and inhibited excessive autophagy activation.
CONCLUSION: Luteolin can significantly inhibit filtering bleb fibrosis after trabeculectomy, which may reduce the degree of fibrosis via the Wnt3a/β-catenin pathway.
