Development of a Novel Rodent Model of Radiation-Induced Implant Capsular Contracture

Radiation-induced implant capsular contracture is a challenging complication of post-mastectomy breast reconstruction. The objective of this thesis was to establish a novel rodent model that replicates the critical properties of this complication. Retired breeder female Sprague-Dawley rats underwent surgery with custom smooth silicone implants placed under the right 4th mammary fat pad. Half these rats received 26Gy of ionizing radiation to the implant and fat pad. Radiated implants had both higher Baker grades of capsular contracture and Kumar scores denoting radiation-induced fibrosis. Irradiated capsules showed increased Masson’s trichrome staining and significantly higher hydroxyproline to total protein ratio compared to controls, collectively indicating higher collagen levels in irradiated capsules. Picrosirius red staining qualitatively demonstrated a trend towards increased red birefringence in irradiated capsules, reflecting denser collagen bundling. This model is therefore a reliable reproduction of radiation-induced capsular contracture, and can be used to evaluate potential preventative and therapeutic non-surgical interventions