Although different NSAIDs have different structures, they all work by blocking cyclo-oxygenase (COX) enzymes. There are two main types of COX enzymes: COX-1 and COX-2. Both types produce prostaglandins; however, the main function of COX-1 enzymes is to produce baseline levels of prostaglandins that activate platelets and protect the lining of the gastrointestinal tract, whereas COX-2 enzymes are responsible for releasing prostaglandins after infection or injury. Prostaglandins have a number of different effects, one of which is to regulate inflammation.
Omega-3 fatty acids have been shown to disrupt inflammation cell signaling pathways by binding to the GPR120 receptor.  This benefit however can be inhibited or even reversed if the ratio of Omega-6 / Omega-3 is too high as Omega-6 serves as a precursor to inflammatory chemicals ( prostaglandin and leukotriene eicosanoids ) in the body.   A high proportion of omega-6 to omega-3 fat in the diet shifts the physiological state in the tissues toward the pathogenesis of many diseases: prothrombotic, proinflammatory and proconstrictive.  Omega-6 competes with Omega-3 for the same rate limiting factor which is required for the health-benefits of Omega-3, directly reducing the action of Omega-3 in addition to pharmacologically counteracting Omega-3 benefits through its own action as a pro-inflammatory agent.