Abstract

Tardive dyskinesia (TD) is a persistent hyperkinetic movement disorder associated with prolonged dopamine D2 receptor blockade, particularly during chronic haloperidol (HP) exposure. Emerging evidence suggests that TD-like pathology is sustained by an interconnected redox–mitochondrial–inflammatory network within striatal circuits; however, the regulatory architecture of this network remains incompletely defined. Hyperoside (HS), a flavonol glycoside with cytoprotective properties, has been implicated in cellular stress-response modulation, yet its role in antipsychotic-induced motor dysfunction remains unclear. In this study, a six-group mechanistic design was employed in which rats received HP (1 mg/kg, i.p., 21 days) to induce TD-like orofacial dyskinesia (OD), quantified by vacuous chewing movements (VCMs) and tongue protrusions (TPs). HS (30 mg/kg, i.p.) was administered alone or in combination with HP, with or without pharmacological inhibition of nuclear factor erythroid 2–related factor 2 (Nrf2) using ML385. HP exposure induced progressive dyskinetic behavior accompanied by oxidative and nitrosative stress, mitochondrial dysfunction, increased pro-inflammatory cytokines, and elevated caspase-3 activity in the striatum. HS significantly attenuated behavioral abnormalities while restoring redox balance, preserving mitochondrial enzyme activities, and reducing inflammatory and apoptotic signaling. Notably, Nrf2 inhibition intensified molecular pathology without proportionally worsening behavioral outcomes, indicating a dissociation between biochemical vulnerability and overt motor expression. Furthermore, ML385 markedly attenuated HS-mediated protection across multiple endpoints. Collectively, these findings support a potential protective role for Nrf2-related regulatory mechanisms in limiting network destabilization in TD-like pathology, while highlighting the importance of integrated stress-response pathways in modulating disease progression.

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