Levofloxacin-Catalase-PLGA Nanoparticles Potentiate Sonodynamic Therapy to Alleviate BCG-Induced Tuberculous Granulomas via PI3K/Akt/VEGF Pathway Suppression in Rats.

PURPOSE: Hypoxic tuberculous granulomas induce vascular dysfunction and severely impede drug penetration. This study aimed to elucidate the molecular mechanism by which sonodynamic therapy (SDT) induces vascular normalization and synergistic immunomodulatory effects.

METHODS

Levofloxacin and catalase co-loaded PLGA nanoparticles (LEV@CAT-NPs) were prepared and characterized. Bacillus Calmette-Guérin (BCG) was used as a surrogate for virulent Mycobacterium tuberculosis due to its high biosafety. Therapeutic efficacy and mechanisms were evaluated in BCG-induced 3D tuberculous spheroids and a rat subcutaneous granuloma model via transcriptomic sequencing, Western blot, immunofluorescence, pharmacokinetic analysis, and bacterial load quantification.

RESULTS

LEV@CAT-NPs exhibited excellent stability and oxygen-generating capacity. SDT effectively alleviated intralesional hypoxia and downregulated HIF-1α and VEGF expression, promoting vascular normalization - evidenced by reduced vascular density, increased pericyte coverage, decreased leakage, improved perfusion, and enhanced tight junctions. Mechanistically, SDT inhibited the PI3K/Akt/VEGF pathway, reduced macrophage VEGF secretion, and induced macrophage apoptosis, thereby suppressing abnormal angiogenesis and improving drug penetration. The treatment also activated innate and adaptive immune pathways, promoting CD3⁺ and CD8⁺ T cell infiltration.

CONCLUSION

The SDT-driven mechano-chemical synergistic strategy effectively induces vascular normalization in tuberculous granulomas, improves drug delivery, and offers a promising approach for treating drug-resistant tuberculosis through microenvironment remodeling.