Investigating the Effect of Luteolin on Interleukin-1β and Tumor Necrosis Factor-α in Inflammation Induced by Lipopolysaccharide in Male Rats

Consumption of herbal flavonoids instead of chemical drugs has increased in the recent years due to fewer side effects as well as affordability. In this study, the effect of luteolin was investigated on inflammation induced by lipopolysaccharide in male rat’s serum by measurement of the proinflammatory factors of IL-1β and TNF-α. Overall, 90 male Wistar rats weighing 180 to 200 grams were chosen and divided to control, Sham (solvent) and positive control (Dexamethasone 15 mg/kg. IP) groups, and also three experimental groups received doses of 5, 15, and 30 mg/kg of luteolin, intraperitoneally.
Half an hour after injecting one of these compounds, lipopolysaccharide (30 μg/kg. IP) was injected. Then, at 4-, 12-, and 24-hour intervals, rats were anesthetized and blood samples were taken. Serum of samples were separated by centrifuging, and then, the samples were transferred to micro-tubes and were stored at -80°C. Measurement of interleukin (IL)-1β and tumor necrosis factor (TNF)-α was conducted by the enzyme linked immunosorbent assay (ELISA) method. Data were analyzed using the SPSS software, version 19. Pre-injection with luteolin in 30 mg/kg dose caused a reduction in IL-1β at 4 (P < 0.05) and 24 hours (P < 0.01) after the LPS injection compared to the control group. Also, luteolin significantly decreased TNF-α level at 12 hours (5 and 30 mg/kg; P < 0.05, 0.01, respectively) and 24 hours (15 and 30 mg/kg; P < 0.05, 0.01, respectively) intervals after LPS injection. Furthermore, IL-1β and TNF-α were significantly decreased by dexamethasone injection at all three time intervals compared with the control. Luteolin caused a significant reduction in IL-1β and TNF-α of serum in acute inflammation induction. This impact is close to the dexamethasone effect as an anti-inflammatory steroid drug.