Animal models of haloperidol (HAL)-induced neurotoxicity and orofacial dyskinesia (OD) have long been used to study human tardive dyskinesia (TD). Similar to patients with TD, these models show strong pathophysiological characteristics such as striatal oxidative stress and neural cytoarchitecture alteration. Naringin (NAR), a bioflavonoid commonly found in citrus fruits, has potent antioxidative, anti-inflammatory, antiapoptotic, and neuroprotective properties. The present study evaluated the potential protective effects of NAR against HAL-induced OD in rats and the neuroprotective mechanisms underlying these effects. HAL treatment (1 mg/kg i.p. for 21 successive days) induced OD development, characterized by increased vacuous chewing movement (VCM) and tongue protrusion (TP), which were recorded on the 7th, 14th, and 21st day of drug treatment. NAR (30, 100, and 300 mg/kg) was administered orally 60 min before HAL injection for 21 successive days. On the 21st day, after behavioral testing, the rats were sacrificed, and the nitrosative and oxidative status, antioxidation power, neurotransmitter levels, neuroinflammation, and apoptotic markers in the striatum were measured. HAL induced OD development, with significant increases in the frequency of VCM and TP. NAR treatment (100 and 300 mg/kg) prevented HAL-induced OD significantly. Additionally, NAR treatment reduced the HAL-induced nitric oxide and lipid peroxide production, increased the antioxidation power and neurotransmitter levels in the striatum, and significantly reduced the levels of neuroinflammatory and apoptotic markers. Our results first demonstrate the neuroprotective effects of NAR against HAL-induced OD, suggesting that NAR may help in delaying or treating human TD in clinical settings.
Keywords: Haloperidol; Naringin; Orofacial dyskinesia; Striatum.