Jingxin Zhidong Formula Alleviates Tic Disorder via Modulation of Microglial IKK/NF-κB Signaling and Striatal Neurotransmitter Homeostasis.

backgroundTic disorder (TD) is a neurodevelopmental condition for which pharmacological treatments are limited and are frequently associated with side effects. Jingxin Zhidong formula (JXZDF) offers a potential alternative therapy; however, its mechanism of action has not been fully elucidated. This study investigated the therapeutic effects of JXZDF on TD and explored underlying mechanisms involving neurotransmitter regulation and microglial IκB kinase/nuclear factor-κB (IKK/NF-κB) signaling, a pathway implicated in both inflammatory activation and metabolic reprogramming.

methodsA TD rat model was established using 3,3'-iminodipropionitrile (IDPN). Rats were treated with low-, medium-, or high-dose JXZDF or aripiprazole for three weeks, after which behavioral scores were assessed. Histology, immunohistochemistry, quantitative reverse transcription-polymerase chain reaction, western blotting (WB), and enzyme-linked immunosorbent assay (ELISA) analyses of striatal tissue were performed to evaluate neuronal morphology, neurotransmitter receptor expression (N-methyl-D-aspartate receptor subunit 1 [NMDAR1], glutamate receptor 1 [GRIA1], gamma-aminobutyric acid type A receptor α1 subunit [GABAARα1], and gamma-aminobutyric acid type A receptor β2 subunit [GABAAβ2]), as well as glutamate and GABA levels. The IKK/NF-κB pathway was examined both in vivo and in lipopolysaccharide-stimulated BV-2 microglial cells using WB, immunofluorescence, and ELISA, with the IKKβ inhibitor IMD-0354 used for mechanistic validation.

resultsJXZDF treatment significantly reduced abnormal behavioral scores in the TD rat model in a dose-dependent manner. Treatment ameliorated striatal neuronal damage and corrected the neurotransmitter imbalance by specifically reducing glutamate and increasing the expression of excitatory receptors (NMDAR1, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors [AMPAR], and glutamate receptor subunit 1 [GluA1]), while increasing GABA and inhibitory receptor expression (GABAARα1 and GABAAβ2). JXZDF also suppressed IKK/NF-κB pathway activation in the striatum of TD rats and in LPS-activated BV-2 cells, as evidenced by reduced IκBα and NF-κB p65 phosphorylation, inhibited NF-κB p65 nuclear translocation, and decreased pro-inflammatory cytokine (interleukin-6 [IL-6], tumor necrosis factor-alpha [TNF-α]) secretion. The anti-inflammatory and neuroprotective effects of JXZDF were reversed by co-treatment with IMD-0354.

conclusionsJXZDF alleviated tic-like behaviors in a TD rat model by restoring striatal excitatory-inhibitory neurotransmitter balance and inhibiting microglial-mediated neuroinflammation. Its therapeutic effect was at least partially mediated by suppression of IKK/NF-κB. These findings provide a pharmacological basis for the clinical application of JXZDF in TD treatment.