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

Abstract

Background: Consumption of herbal flavonoids instead of chemical drugs has increased in the recent years due to fewer side effects as well as affordability. Objectives: 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. Methods: 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. Results: 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. Conclusions: 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.