Huazhuo Decoction Contributes to Immune Homeostasis and Attenuates Neuronal Inflammation and Demyelination in a Mouse Model of Multiple Sclerosis.

Background: Multiple sclerosis (MS) is an autoimmune inflammatory disease of the central nervous system (CNS). Huazhuo decoction (HD) has been shown to ameliorate disease progression in MS patients, but the underlying mechanisms remain poorly understood. Purpose: This study sought to assess the therapeutic efficacy of HD in an experimental autoimmune encephalomyelitis (EAE) model of MS, and to further investigate the underlying mechanisms involved. Methods: We assessed the curative effects of HD on EAE mice via neurological function scoring and histological staining and identified the chemical composition of HD by UPLC-MS. RNA sequencing identified differentially expressed genes. Flow cytometry detected the proportions of splenic Th17, Th1, and Treg cells. Expression of key molecules was evaluated by Western blotting and quantitative PCR. Immunofluorescence was used to monitor microglia, astrocytes and oligodendrocytes. Results: HD alleviated neurobehavioral impairment, inflammatory infiltration and demyelination in EAE mice. RNA sequencing revealed that HD may ameliorate EAE by modulating adaptive immunity and affecting NLRP3-related signaling pathways. Further studies demonstrated that HD suppressed the upregulation of NF-κB/NLRP3 pathway, balanced the proportions of peripheral Th17, Th1 and Treg cells and regulated inflammatory cytokines. HD influenced innate immunity by reducing microglia and astrocytes and increasing oligodendrocytes in the CNS. Notably, these protective effects of HD were attenuated by an NLRP3 agonist. Conclusion: HD effectively alleviated the clinical symptoms of EAE mice and inhibited both peripheral and central immune inflammatory responses by modulating the NF-κB/NLRP3 pathway, providing a strong basis for its clinical application.