Hydrogen combined with needle-embedding therapy alleviates traumatic brain injury by inhibiting NLRP3 inflammasome activation via STING signaling pathway

Abstract

Background

Traumatic brain injury (TBI) is a primary cause of disability and death worldwide and with unmet effective therapies. Molecular hydrogen (H₂) exerts latent therapeutic means for TBI. Nevertheless, few studies have illustrated the roles of hydrogen combined with needle-embedding therapy (H₂ + NET) in TBI and its exact mechanism remains unclear. Here, we elucidated the underlying mechanisms of H₂ + NET in the TBI progression.

Methods

Controlled cortical impact (CCI) method was conducted to construct TBI mouse model. The mNSS test was used for neurological function measurement. Nissl staining for evaluating neuronal injury, TUNEL assay for determining neuronal apoptosis and ELISA assay was applied for adenosine, ATP level and inflammatory cytokines determination. The relative mRNA levels of inflammatory elements were assessed by qRT-PCR analysis. Iba-1, NLRP3 and STING expression were determined through immunofluorescence staining. The expression of NLRP3 inflammasome related proteins and STING signaling pathway associated proteins were evaluated using Western blot.

Results

H₂ or NET treatment mitigated brain injury and reduced brain water content in CCI-induced TBI mouse model. CCI induction promoted microglia activation and inflammatory response, thereby activating the NLRP3 inflammasome activity and STING signaling pathway, which was partly reversed by H₂ or NET treatment. However, H₂ + NET significantly ameliorated brain oedema, and further inhibited inflammatory response, NLRP3 inflammasome activation and STING pathway activation in TBI mice when compared to the H₂ or NET alone treatment group.

Conclusion

Hydrogen combined with needle-embedding therapy acts as a promising intervention method for TBI through inhibiting NLRP3 inflammasome activation via STING signaling pathway.