Effect of emu oil on auricular inflammation induced with croton oil in mice

Objective-To determine the acute anti-inflammatory effects of topically app lied emu oil. Animals-96 male CD-1 mice assigned randomly to 4 groups, each comprising 24 mice. Procedure-To induce auricular inflammation, 50 mu l of a solution comprisin g 10 mu l of croton oil dissolved in 1 ml of acetone was applied to the inn er surface of the left auricle (pinna). One hour later, 3 or 5 mu l of emu oil (low- and high-dose groups, respectively) or 5 mu l of porcine oil (oil -control) was applied to the left pinna. Control mice remained untreated. S ix mice per group were euthanatized 3, 6, 12, and 24 hours after induction of inflammation. Specimens of auricular tissue (ear plugs) were obtained, u sing a 6-mm biopsy punch. Magnitude of swelling was calculated as the weigh t difference between left (inflamed) and right (noninflamed) ear plugs; deg ree of edema was determined as the difference between wet and dry weights o f the left ear plug. Results-Magnitude of swelling was significantly reduced at 6 and 12 hours i n mice treated with emu or porcine oil, compared with controls. The greates t reduction in swelling was detected in the high-dose emu group at 6 hours. Compared with controls, degree of edema was significantly reduced at 6 hou rs only in the high-dose group, whereas by 12 hours, all groups treated wit h oils had significantly less edema than controls. At 24 hours, magnitude o f swelling and degree of edema did not differ among groups. Conclusion-Topically applied emu oil significantly reduced severity of acut e auricular inflammation induced by croton oil in mice.