Preparation optimization and protective effect on 60Co-γ radiation damage of Pinus koraiensis pinecone polyphenols microspheres

Here, the chitosan and the glutaraldehyde (GA) were used to encapsulate pinecones polyphenols of Pinus koraiensis (P. koraiensis) by emulsification cross-linking technology. First, the prepared parameters (crosslinking agent amount, stirring speed, crosslinking temperature and emulsifying time) of the pinecones polyphenols microspheres (PPMs) were optimized by the response surface methodology (RSM). When chitosan concentration and crosslinking time were 2% and 80 min, respectively, the optimal conditions were 7.91 mL of crosslinking agent, stirring speed of 660.98 r/min, crosslinking temperature of 41.18 °C and emulsifying time of 198.65 min. The prepared PPMs embedding rate was 73.57%. The optimized PPM possessed a distinct core-shell structure and uniform spherical distribution with a particle size value of 3.4 μm. In addition, they had the excellent sustained-release characteristics in vitro. We also evaluated the radioprotective effects of PPMs against 60Co-γ radiation in vivo. PPMs improved significantly the activity of the antioxidant enzyme SOD and reduce MDA level in the plasma of irradiated mice. Accordingly, PPMs could also significantly enhance the immunomodulation activity by promoting the proliferation of splenocytes and monocyte phagocytosis of irradiated mice. These results suggested that PPMs exert effective protection against radiation-induced injury by improving the antioxidant and immunomodulation activities.