Quercetin ameliorates lipopolysaccharide-induced neuroinflammation and oxidative stress in adult zebrafish.

ABSTRACT

BACKGROUND: Quercetin is a natural flavonoid that is known to have numerous pharmacological activities such as antioxidative, anti-inflammatory, and neuroprotective effects against various neurological disorders. Lipopolysaccharide (LPS) is a potent endotoxin, reported causing several neurological disorders. AIM: The present study was designed to investigate the possibility that quercetin ameliorates LPS induced oxidative stress and neuroinflammation in adult zebrafish. MATERIALS AND METHODS: Zebrafish (weighing 470-530 mg) were treated with a single injection of LPS (1 mg/kg) intraperitoneally (i.p.) followed by post-treatment with quercetin (50 and 100 mg/kg; i.p.) for 7 days. After sacrificing brain was harvested and subjected for biochemical, molecular, and histological analyses. RESULTS: Results revealed post-treatment with quercetin was able to ameliorate the behavioral abnormalities as in novel tank diving test- time spent in the top zone (TSTZ), and the number of entries in the top zone was significantly (p < 0.01) more as compared to time spent in the bottom zone (TSBZ). In the light-dark chamber test- time spent in the light zone (TSLZ), and the number of entries in the light zone were significantly (p < 0.01) more as compared to time spent in the dark compartment (TSDC). Additionally, results of histopathology (H & E stain) studies showed less disruption in neuronal cells as compared to the LPS treated group. Moreover, the results of the molecular analysis revealed that quercetin treatment significantly (p < 0.01) decrease TNF-α and IL-1ß levels as compared to LPS treated animals. Further, results of the biochemical analysis reveal that quercetin significantly (p < 0.01) reduces the level of LPO, nitrite, AChEs and increases anti-oxidant GSH. CONCLUSION: Quercetin treatment helps to prevent oxidative damage and neuroinflammation in LPS treated adult zebrafish.