Lidocaine-Based Derivatives for the Treatment of Staphylococcal Enterotoxin B-Induced Chronic Rhinosinusitis

Lidocaine exhibited anti-inflammatory and immunomodulatory properties. This study aimed to investigate the anti-inflammatory effects of the lidocaine-derived analogs, EI137 and EI341, in a Staphylococcal enterotoxin B (SEB)-induced chronic rhinosinusitis (CRS). A CRS model was established using BALB/c mice via intranasal instillation of SEB. EI137 and EI341 were administered intranasally at 0.5 μg/g and 5 μg/g, respectively. Nasal symptoms and interleukin (IL)-4, IL-10, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α levels in the nasal lavage fluid (NLF) were assessed. The reverse-transcription polymerase chain reaction was used to identify IFN-γ, IL-4, IL-10, and their transcription factors in the sinonasal mucosa. Histological changes were performed to assess inflammatory cell infiltration, epithelial thickness, and mucus-producing cells. SEB induced significant increases in IL-4, IL-10, and TNF-α levels in NLF and sinonasal mucosa, along with marked inflammatory cell infiltration. Intranasal EI137 and EI341 administration significantly reduced Th2 cytokine and its transcription factor, inflammatory cell infiltration, and mucus-producing cell numbers in the sinonasal mucosa. Further, EI137 suppressed Th1 cytokines, whereas EI341 enhanced Th1 responses. Both compounds promoted regulatory T cell responses, as evidenced by increased IL-10 and Foxp3 mRNA expression. EI137 and EI341 demonstrated potent local anti-inflammatory effects in a SEB-induced CRS model by modulating Th2 and Treg responses. EI137 suppressed Th1 inflammation, whereas EI341 enhanced it. These results indicate that EI137 and EI341 are promising topical agents for Th2-dominant inflammatory diseases, with distinct effects on Th1 immune responses.