Targeting antifungal therapy with Dectin-1-coated solid lipid nanoparticles in a rat model of spinal fungal infection

Spinal fungal infection remains a major therapeutic challenge due to the limited efficacy of conventional antifungal agents. We aimed to develop itraconazole (ITZ)-embedded solid lipid nanoparticles (SLNs) coated with the β-glucan receptor Dectin-1 (DEC@ITZ-SLN) for targeted antifungal therapy in a rat spinal fungal infection model. SLNs were synthesized and embedded with ITZ (ITZ-SLN). Dectin-1, a β-glucan receptor that binds fungal cell walls, was attached to ITZ-SLN (DEC@ITZ-SLN). DEC@ITZ-SLN did not cause damage to the erythrocyte cell membrane and effectively inhibited fungal growth by targeting the fungal cell membrane. In vitro, DEC@ITZ-SLN exhibited enhanced antifungal effect compared to ITZ-SLN, accompanied by suppression of the extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) pathways in fungal-infected cells. In rats with spinal fungal infection, DEC@ITZ-SLN was administered intravenously via the tail vein for 7 days. DEC@ITZ-SLN reduced the fungal burden within vertebral tissues, as shown in periodic acid-Schiff (PAS) staining and immunofluorescence (IF) staining results. Magnetic resonance imaging (MRI) showed that the extent of the infection was reduced more in the DEC@ITZ-SLN group compared to the Infection and ITZ-SLN groups. The systemic inflammatory markers, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels, were significantly decreased in the DEC@ITZ-SLN group. These results suggest DEC@ITZ-SLN as a promising targeting therapeutic agent for spinal fungal infection.