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

Background Tic 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. Methods A 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. Results JXZDF 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. Conclusions JXZDF 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.