Here is where the COX comes in. COX-1 and COX-2 are enzymes that convert arachidonic acid into usable molecules. In very general terms COX-1 is responsible for making housekeeping type molecules, the ones that protect the gut and keep the kidneys working. COX-2 is the enzyme that makes the inflammatory molecules. In reality it isn’t that simple and box COX enzymes overlap in function but we are keeping it simple.
COX converts AA into PGH2 which is then further into five different prostanoids, Thromboxane, PGD2, PGI3, PGF2, and PGE2. The prostanoid we care about right now is prostaglandin E2 (PGE2). PGE2 is an inflammatory mediator and is responsible for the classic signs of inflammation: redness, swelling, pain, and warmth or if you wanna impress your friends using Latin: rubor, tumor, dolor, and calor.