A study on the mechanism of Bushen Kaiqiao Formula in modulating microglial activation to alleviate neuroinflammation in ADHD.

BACKGROUND: Growing evidence suggests that dysregulated microglial activation and neuroinflammation in the prefrontal cortex may underlie the pathophysiology of Attention Deficit Hyperactivity Disorder. Utilizing spontaneously hypertensive rats-a well-validated animal model of ADHD-this study aimed to characterize ADHD-like behavioral phenotypes and prefrontal cortical neuronal development and elucidate the neuroimmunological mechanisms through which the Bushen Kaiqiao Formula (BSKQF) exerts its therapeutic effects by modulating microglial activation states. METHODS: Ultra-high-performance liquid chromatography coupled with a tandem mass spectrometer (UHPLC-MS/MS) was used to qualitatively analyze the chemical composition of Bushen Kaiqiao Formula, and network pharmacology was applied to predict its potential therapeutic targets and ADHD-related pathways ADHD-like behaviors, including hyperactivity, impulsivity, spatial memory, and attention, were assessed using the Open Field Test, Elevated Plus Maze, and Y-Maze Test at weeks 2 and 4. Prefrontal cortical neuronal morphology and dendritic spine density were evaluated using Nissl staining and Golgi-Cox staining, respectively. Microglial activation (Iba-1+/iNOS + immunofluorescence), inflammatory cytokine levels (IL-1β and IL-6 by ELISA), and blood-brain barrier integrity (transmission electron microscopy) were examined. In vitro, primary prefrontal cortical neurons and microglia were isolated from neonatal rats and treated with BSKQF-containing serum at different concentrations, with Methylphenidate (MPH) as a control. An oxygen-glucose deprivation/reoxygenation (OGD/R) model was established to mimic neuroinflammatory conditions with inflammatory signaling pathways assessed. RESULTS: UHPLC-MS/MS identified key bioactive components of Bushen Kaiqiao Formula. Network pharmacology analysis suggested that BSKQF may ameliorate ADHD-related behavioral deficits by inhibiting the NF-κB signaling pathway. Behavioral assessments demonstrated dose- and time-dependent effects. BSKQF significantly reduced neuronal loss, promoted synaptic plasticity, reduced the proportion of activated microglia (iNOS+/Iba-1+), and lowered IL-1β and IL-6 levels. Additionally, ultrastructural examination indicated restored blood-brain barrier integrity and reduced perivascular edema. In vitro, BSKQF-containing serum suppressed NF-κB pathway activation (p-NF-κB-p65, p-IκBα) and inflammasome-related proteins (NLRP3, caspase-1). CONCLUSION: BSKQF effectively alleviates ADHD-like behaviors in SHR rats by inhibiting prefrontal microglial activation and neuroinflammation, reducing neuronal apoptosis, restoring synaptic plasticity, and preserving blood-brain barrier integrity.