Therapeutic Effect of Baicalin-Loaded Thermosensitive Liposomal Hydrogel in Autoimmune Uveitis

Autoimmune uveitis (AU) is a chronic intraocular inflammatory disease that can lead to irreversible vision loss. Current pharmacotherapies are often associated with serious systemic adverse effects, limited ocular bioavailability, and high recurrence rates. Therefore, developing a safe and sustained local delivery system that effectively regulates ocular inflammation remains an urgent clinical challenge. Baicalin (BA) exerts immunomodulatory effects by activating the aryl hydrocarbon receptor (AhR), yet its poor solubility and instability hinder its clinical application. To address these limitations, this study developed BA-loaded liposomes (BA-Lip) and incorporated them into a chitosan/β-glycerophosphate (CS/β-GP) thermosensitive hydrogel (BA-Lip@CG) to enable localized and sustained BA delivery for AU treatment, and further evaluated its therapeutic efficacy and underlying mechanisms. BA-Lip and BA-Lip@CG were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and rheological analysis. The biocompatibility of BA-Lip@CG was evaluated in ARPE-19, HCEC, and RAW264.7 cells using the CCK-8 assay, and its in vitro anti-inflammatory and antioxidative effects were detected by ELISA and fluorescence staining. In vivo, an experimental autoimmune uveitis (EAU) mouse model was established, with assessments including clinical scoring, retinal histopathology, ROS staining, ELISA for retinal cytokines, Western blot analysis of AhR expression, and flow cytometry for Treg/Teff subsets. BA-Lip@CG exhibited uniform particle size, a positive zeta potential, rapid in situ gelation at ocular surface temperature, and sustained BA release over 96 h. In vitro, it demonstrated excellent cytocompatibility and significantly suppressed IL-6, IFN-γ, and IL-17A secretion, as well as ROS accumulation, outperforming free BA. In vivo, BA-Lip@CG markedly attenuated ocular inflammation, restored retinal architecture, and decreased oxidative stress in EAU mice. Mechanistically, BA-Lip@CG upregulated retinal AhR expression, increased CD4⁺ FoxP3⁺ Tregs, and decreased CD4⁺ IFN-γ⁺ Th1 and CD4⁺ IL-17A⁺ Th17 cells, confirming its potent immunoregulatory activity. Overall, the BA-Lip@CG thermosensitive hydrogel enables sustained BA delivery, enhances ocular retention, and delivers potent anti-inflammatory, antioxidative, and immunomodulatory effects, supporting its potential as a promising therapeutic strategy for AU.