Neuroprotective effect of naringin, a flavone glycoside in quinolinic acid-induced neurotoxicity: Possible role of PPAR-γ, Bax/Bcl-2, and caspase-3.

Background: Huntington's disease (HD) is a complex multifactorial neurodegenerative disorder. Naringin, a flavanone glycoside exhibits potent anti-inflammatory and antiapoptotic effect.

Aim: To evaluate the effect of naringin in quinolinic acid (QA)-induced neurotoxicity in laboratory rats.

Methods: Neurotoxicity was induced in male Wistar rats by single intrastriatal injection of QA (300 nmol/4 μl saline) in striatum except non-treated. Rats were administered orally with either vehicle (distilled water (10 mL/kg) or naringin (20, 40 and 80 mg/kg) or pioglitazone (40 mg/kg, p.o.) or its combination for 28 days.

Results: Naringin (40 and 80 mg/kg) treatment significantly (p < 0.05) attenuated QA-induced alterations in locomotor activity, rearing, grooming, neurological score, footprint analysis, grip strength and a number of slips. QA-induced altered striatal oxido-nitrosative stress (superoxide dismutase, glutathione, malondialdehyde and nitric oxide), neuroinflammatory markers (TNF-α, IL's and NF-kB mRNA) and apoptotic markers (Bax-Bcl-2, Caspase-3, and PPAR-γ mRNA) were significantly attenuated by (p < 0.05) by naringin. It also significantly increased (p < 0.05) mitochondrial complex (I-IV) activity. TTC scanning also showed that naringin treatment significantly reduced (p < 0.05) QA-induced striatal degeneration. It also significantly decreased (p < 0.05) OVA-induced elevated striatal apoptosis revealed by flow-cytometric analysis.

Conclusion: Naringin exerts its neuroprotective effect against QA-induced neurotoxicity via modulation of oxido-nitrosative stress, neuroinflammatory, apoptotic markers and mitochondrial complex activity. Thus, it may offer a better therapeutic alternative for the management of HD like symptoms.