animal model; ceramics; foreign-body reaction; urethral bulking; voiding function

ObjectivesTo develop an economic, practical and readily available animal model for preclinical testing of urethral bulking therapies, as well as to establish feasible experimental methods that allow for complete analysis of hard microparticle bulking agents.MethodsAlumina ceramic beads suspended in hyaluronic acid were injected into the proximal urethra of 15 female rats under an operating microscope. We assessed overall lower urinary tract function, bulking material intraurethral integrity and local host tissue response over time. Microphotographs were taken during injection and again 6months postoperatively, before urethral harvest. Urinary flow rate and voiding frequency were assessed before and after injection. At 6months, the urethra was removed and embedded in resin. Hard tissue sections were cut using a sawing microtome, and processed for histological analysis using scanning electron microscopy, light microscopy and immunohistochemistry.