Gamma-Irradiation Impact on Decellularized Placental Membrane as a Natural Scaffold for Wound Care Applications

Introduction: Placental membrane grafts have been clinically used in various wound care applications. A recently developed full thickness, decellularized, lyophilized, and terminally sterilized placental membrane product* has been introduced as a novel wound dressing material.

A study was performed to investigate the impact of terminal sterilization (gamma-irradiation) on this decellularized placental membrane by investigating the local tissue response and remodeling in an athymic mouse subcutaneous implantation model.

Methods: Placental membranes recovered from authorized donors were decellularized, lyophilized, and half of membrane were terminally sterilized by low dose gamma-irradiation at ultra-low temperature. The placental membrane samples as 12 mm punches with and without gamma-irradiation were subcutaneously implanted in the dorsal side of the athymic mice bilaterally for 2, 3, 4, 6, 8, and 10 weeks. All explants were formalin fixed, bisected, and paraffin embedded. The cross sections were stained with hematoxylin & eosin, or Russell Movat pentachrome, and assessed for vimentin, pan muscle actin, and CD206 via immunohistochemistry methods.

Results: Histological analysis showed that local host tissue responses were not significantly different between 2 tested groups during the entire implantation period. Fibroblast-like cell infiltration followed by angiogenesis occurred in all three layers of the placental membrane as early as 2 weeks after implantation. No signs of chronic inflammation, necrosis, or fibrosis were observed. Presence of CD206+ macrophages and fibrocytes inside implants demonstrated active tissue remodeling and healing. All three layers of placental membrane were present at the end of the study.

Discussion: Terminal sterilization did not have a negative impact on local tissue responses and remodeling of subcutaneously implanted decellularized placental membranes. Full thickness decellularized, lyophilized, and gamma-irradiated placental membrane grafts* facilitated cell infiltration and angiogenesis by 2 weeks of application and may stay in place longer to support wound healing.