Clonidine Ameliorates Neuroinflammation in the Rat Model of Tourette Syndrome.

Neuroinflammation plays a vital role in the etiology and pathogenesis of Tourette syndrome (TS). The postmortem report of TS patients clarified that IL-2 is elevated in the basal ganglia region, supporting neuroinflammation of TS. α₂ receptor agonist (clonidine) is one of the primary drugs for treating tic disorders; supported by clinical and animal experiments, α₂ receptor agonists have potential anti-inflammatory effects. This article aims to explore the impact of clonidine on neuroinflammation with TS and to reveal the possible mechanism of clonidine-mediated neuroinflammation with TS. Thirty P21 SD rats were randomly divided into a TS rat group (n = 20) and a normal control group (n = 10). After successful TS modelling, rats were randomly divided into the clonidine intervention group (n = 10) and the TS group (n = 10). The clonidine intervention group received clonidine 0.1 mg/kg by gavage daily for seven consecutive days. After behavioural evaluation on day 8, the brain was removed from the head. The striatum was separated from one side of the brain and subjected to ELISA to detect cytokines. The other side of the brain was subjected to immunohistochemical detection for microglial activation, and the integral optical density value was calculated using image software for comparison between the groups. Compared to the normal group, IL-2 cytokine levels in TS rats were significantly higher (P < 0.05). In the clonidine group, IL-2 levels (213.82 ± 121.48 pg/ml) were significantly lower than in the TS group (322.61 ± 79.27 pg/ml) (P < 0.05) but not significantly different from the normal control group (257.40 ± 95.80 pg/ml) (P > 0.05). Immunohistochemical analysis showed significant microglial activation in TS rats (IOD = 22.10 ± 6.67) compared to the normal group (IOD = 11.58 ± 4.36) (P < 0.05). Clonidine administration reduced microglial activation, with a significant difference between the TS + clonidine group (IOD = 15.97 ± 8.03) and TS rats (P < 0.05). Clonidine can suppress the neuroinflammatory response in Tourette syndrome, and its inhibitory effect on the neuroinflammatory response may be a potential beneficial effect of this treatment.