Vitamin D alleviates intracerebral hemorrhage symptoms by modulating pro-inflammatory/anti-inflammatory phenotypic transformation of microglia through P2X7R activation of NLRP3

Objective: The primary objective of this study was to analyze the potential influence of vitamin D on microglial phenotypic transformation in cerebral hemorrhage.

Methods: To simulate cerebral hemorrhage conditions, a hemin-induced brain hemorrhage cell model was established, and cell viability was subsequently measured by CCK-8 assay. Western blotting was then performed to detect the expression of P2X7R, NLRP3, and microglial phenotypic transformation marker proteins. The expression of CD16/32 and CD206 was assessed by immunofluorescence, and ELISA was used to measure levels of inflammatory cytokines, including IL-4, TNF-α, IL-1β, IL-10, and IL-6.

Results: Vitamin D exhibited a stimulating effect on cell proliferation, reduced the expression of CD16/32 and iNOS, and boosted the expression of CD206, Arg-1, and Iba-1. Moreover, vitamin D inhibited TNF-α, IL-1β, and IL-10 levels and elevated IL-4 and IL-6 levels. This implies that vitamin D can suppress pro-inflammatory phenotypic transformation and promote anti-inflammatory phenotypic transformation in microglia. Additionally, vitamin D suppressed the expression of P2X7R and NLRP3. The effect of P2X7R inhibitor (A438079) treatment was comparable to that of vitamin D, with the addition of vitamin D further enhancing the effect.

Conclusion: Vitamin D was found to regulate microglial phenotypic transformation through the P2X7R/NLRP3 signaling pathway, thereby promoting anti-inflammatory and inhibiting pro-inflammatory phenotypic transformation. This finding may lead to new therapeutic strategies for the treatment of ICH-related brain injury.