Effect of radiation sterilization on the ability to induce adipose regeneration in vivo in decellularized adipose-derived matrix.

Background: Decellularized adipose-derived matrix (DAM), a biological scaffold that can induce adipose regeneration. The balance between its sterilization efficiency and its ability to maintain in situ adipose regeneration should be considered in terminal sterilization. The purpose of this study was to investigate the effects of radiation sterilization of cobalt-60 ( Co)with different doses on adipogenesis induced by different forms of DAM, so as to reduce radiation dose under the premise of safe and effective sterilization and ensure adipogenesis induced by DAM in vivo.

Methods: High dose (25 kGy) and low dose (5 kGy) radiation were used to sterilize freeze-dried and wet DAM, respectively. The sterilization efficiency, macro and micro characteristics, mechanical and mechanical properties of DAM were compared, and then implanted into the immunocompromised mice to evaluate the adipose regeneration.

Results: Under the two radiation doses, no microbial growth was found in the freeze-dried and wet DAM sterility tests, and no significant changes were observed in the macro and micro structures. In terms of mechanical properties, the elastic modulus of high dose freeze-dried DAM decreased significantly (p < 0.001). In vivo animal experiments, the freeze-dried DAM irradiated with high dose almost completely lost its function of adipogenesis in vivo. Although the wet DAM irradiated with high dose could induce fat regeneration in the early stage, the adipocyte deformation and atrophy appeared in the later stage. The freeze-dried and wet DAM after low dose irradiation was similar to the wet DAM without irradiation in the blank control, which could maintain excellent adipogenic and angiogenic functions in vivo.

Conclusion: High dose Co irradiation can completely destroy the ability of freeze-dried DAM to induce adipose regeneration in situ, while low dose irradiation (5 kGy) can effectively sterilize the DAM without damaging in vivo induced adipose regeneration. Radiation has more damage to freeze-dried DAM than wet DAM in adipogenesis properties.