Emu Oil Reduces LPS-Induced Production of Nitric Oxide and TNF-α but not Phagocytosis in RAW 264 Macrophages

Abstract

Emu is the second-largest extant bird native to Australia. Emu oil, obtained from the emu's fat deposits, is used as an ingredient in cosmetic skincare products. Emu oil has been reported to improve several inflammatory symptoms; however, the mechanisms of these anti-inflammatory effects are largely unknown. This study investigated the effects of emu oil on the inflammatory macrophage response in vitro. A murine macrophage cell line, RAW 264, was incubated in culture media supplemented with or without emu oil and stimulated with lipopolysaccharide (LPS). We determined phagocytic activity by measuring the number of fluorescent microspheres taken up by the cells. The phagocytic activity of RAW 264 cells in the presence of LPS was unaffected by emu oil. We also determined production of nitric oxide (NO) and tumor necrosis factor (TNF)-α in the culture medium using the Griess reaction and an enzyme-linked immunosorbent assay, respectively, and the protein expression of inducible NO synthase (iNOS) using western blotting. The results indicated that emu oil reduced the LPS-induced production of NO, TNF-α, and iNOS expression in a dose-dependent manner. The results suggested that emu oil does not reduce the phagocytic clearance rate of inflammatory matter; however, it does reduce the production of NO and TNF-α in macrophages. These latter products enhance the inflammatory response and emu oil thereby demonstrated anti-inflammatory properties.

Modulation of Macrophage Function by Lactobacillus-Conditioned Medium

“…NO, formed from arginine by nitric oxide synthases (iNOS), and its downstream reactive nitrogen intermediates (RNIs) are toxic to microbes and host cells via cysteine S-nitrosation of proteins, deamination of nucleic acids, and desaturation of lipids (Nathan and Cunningham-Bussel, 2013). There is evidence that reduction NO does not interfere with macrophage phagocytosis (Miyashita et al, 2018). This is inconsistent with our study using pharmacological inhibition of NO production with L-NMMA which was found to reduce bacterial killing, although, increase production of NO with LPS had no effect on bacterial killing mechanism.…”

Carcass traits and fat quality of breeding emu (Dromaius novaehollandiae) in Northern Japan

“…Over the past several decades, emus have become a novel poultry species producing low-fat red meats, low allergenic eggs, and oils containing rich unsaturated fatty acids ( USFAs ). In particular, emu oil exhibits anti-inflammatory effects ( Snowden and Whitehouse, 1997 ; Miyashita et al, 2018 ) and reduces melanin production in melanoma cells ( Ito et al, 2016 ). Emu oil also has high economic value as a skincare product ( Politis and Dmytrowich, 1998 ; Zanardo et al, 2017 ).…”

Carcass Traits and Fat Quality of Breeding Emu (Dromaius Novaehollandiae) in Northern Japan

“…Over the past several decades, emus have become a novel poultry species producing low-fat red meats, low allergenic eggs, and oils containing rich unsaturated fatty acids (USFAs). In particular, emu oil exhibits anti-in ammatory effects [2,3] and reduces melanin production in melanoma cells [4] . Emu oil also has high economic value as a skincare product [5,6] .…”