Albendazole-doxycycline combination therapy alleviates MRI- and pathology-evident neuroinflammation and restores IL-33/GFAP balance in mouse neuroangiostrongyliasis.

BACKGROUND: Angiostrongylus cantonensis (rat lungworm) infection causes neuroangiostrongyliasis, a parasitic disease characterized by eosinophilic meningitis and meningoencephalitis. Within the central nervous system (CNS), larval migration and degeneration provoke neuroinflammation involving microglia and astrocytes. Albendazole (ABZ) is the mainstay treatment but may exacerbate inflammation through antigen release from dying worms. Doxycycline (DOX), a tetracycline antibiotic with anti-inflammatory and neuroprotective properties, can attenuate glial activation and matrix metalloproteinase activity. As a follow-up to our previous work on ABZ-DOX treatment outcomes, this study evaluated whether ABZ-DOX co-therapy (co) provides antiparasitic and neuroprotective benefits associated with interleukin (IL)-33/glial fibrillary acidic protein (GFAP) regulation in A. cantonensis-infected mice. METHODS: A laboratory-maintained Taiwan strain of A. cantonensis was used to infect 7-8-week-old C57BL/6 and BALB/c mice (50 third-stage larvae/mouse). For terminal analyses (histopathology, western blotting, and enzyme-linked immunosorbent assay [ELISA]), animals were allocated to eight groups: uninfected control, infected untreated, early ABZ (7-21 days post infection [dpi]), late ABZ (14-21 dpi), early DOX (7-21 dpi), late DOX (14-21 dpi), early ABZ-DOX co-therapy (co; 7-21 dpi), and late co-therapy (co; 14-21 dpi); all were euthanized at 21 dpi. Parasite recovery was performed in an independent cohort following the early-treatment schedule. Magnetic resonance imaging (MRI; 7.0 T) was conducted in a separate longitudinal BALB/c cohort (infected untreated versus early co) scanned up to 28 dpi. Statistical analyses were conducted using t-tests. RESULTS: In an independent cohort treated using the early schedule (7-21 dpi), ABZ-containing regimens reduced worm recovery to near-zero levels in both strains. Histopathology showed eosinophilic meningitis, perivascular inflammation, and hemorrhagic changes in infected brains; these lesions were reduced in treated groups, with the most consistent improvements observed in the early co-therapy group relative to infected untreated controls. In a separate longitudinal MRI cohort (BALB/c; infected untreated versus early co-therapy), T2-weighted images demonstrated reduced hyperintensity and edema-like signal changes after early co-therapy. Western blot analyses indicated infection-associated GFAP upregulation and IL-33 alterations across brain regions, whereas co-therapy shifted these markers toward uninfected levels in a region- and strain-specific manner. Serological ELISA showed increased A. cantonensis-specific immunoglobulin (Ig)A/G/M reactivity in infected mice, which was reduced in treated groups. CONCLUSIONS: ABZ-DOX co-therapy was associated with reduced parasite recovery and multilevel improvements across pathology, MRI, and glial markers in mice neuroangiostrongyliasis. These findings support ABZ-DOX co-therapy as a candidate regimen for further investigation in the management of A. cantonensis-associated neuroinflammation.