Expression of cyclooxygenase-2 in the periprosthetic capsule surrounding a silicone shell implant in the rat.

Prosthetic breast implants are used frequently for both aesthetic and reconstructive purposes. Histologically, the normal tissue response to silicone implants typically involves an inflammatory infiltrate that consists initially of macrophages, and later consists of fibroblasts, myofibroblasts, and lymphocytes. To characterize further the nature of the inflammatory response to silicone breast implants, the authors evaluated the expression of the enzyme cyclooxygenase-2 (COX-2) by the tissues and cells of the breast capsule after silicone augmentation in an animal model. COX-2 is an inducible enzyme that is expressed primarily in response to inflammatory stimuli and mediates the production of prostaglandins that support the inflammatory process. Fifty-nine animals at five time points were evaluated. Specifically, on days 4, 7, 14, 28, and 80 the authors identified cytoplasmic COX-2 expression in each of the three cell types of interest, including endothelial cells, macrophages, and fibroblasts. Selective COX-2 inhibiting agents may be an appropriate pharmacological intervention for modulating the formation of periprosthetic capsules.