Effects of quercetin on antioxidant and anti-inflammatory properties of goat rumen epithelial cells stimulated with lipopolysaccharide

The aim of this study was to investigate the effects of quercetin on the antioxidant and anti-inflammatory responses of goat rumen epithelial cells (GRECs) stimulated by lipopolysaccharide (LPS). GRECs were initially cultured in basal medium containing 0, 5, 10, 20, 40, 60, 80, 120, 160, and 320 μg·mL⁻¹ quercetin for 6 h. On the basis of the measurement of cell activity, a quercetin concentration of 80 μg·mL⁻¹ was used in subsequent experiments, which had the following four treatment groups: GRECs cultured in basal medium without quercetin or LPS (control group, Con); basal medium containing 80 μg·mL⁻¹ quercetin (Q); basal medium containing 1 μg·mL⁻¹ LPS (L); and basal medium containing 80 μg·mL⁻¹ quercetin and 1 μg·mL⁻¹ LPS (L + Q). Relevant indices of GRECs were determined after 6 h of culture. The following results were obtained. 1) Compared with the control group, the activities of catalase (CAT) and superoxide dismutase (SOD) were significantly reduced in group L (P < 0.05), whereas the content of malondialdehyde (MDA) was significantly increased (P < 0.05). In group Q, compared with the control group, the activities of CAT, SOD, and glutathione peroxidase (GSH-PX), and total antioxidant capacity were significantly increased (P < 0.01), whereas the content of MDA was significantly reduced (P < 0.05). Compared with group L, the activities of CAT, SOD, and GSH-PX, and total antioxidant capacity were significantly increased in the L + Q group (P < 0.05). 2) Compared with the control group, relative mRNA transcript levels of the IK cytokines CCL5, CXCL6, CXCL8, IL-6, TNF-α, and IL-1β were significantly elevated in group L (P < 0.01), whereas compared with group L, the relative mRNA transcript levels of these six cytokines were significantly reduced in the L + Q group (P < 0.01). 3) Compared with the control group, the relative mRNA transcript levels of TLR 2, NF-κB, MyD 88, and IRF3 were significantly elevated in group L (P < 0.05), whereas those of TOLLIR and TLR 4 were significantly reduced in group Q (P < 0.05). Furthermore, compared with group L, the relative mRNA transcript levels of TLR 2, NF-κB, MyD 88, TOLLIR, and TLR 4 were significantly reduced in the L + Q group (P < 0.05). In conclusion, quercetin can enhance the antioxidant and anti-inflammatory properties of goat rumen epithelial cells and promote cell proliferation.