The Conglutinant Role Of Sustained-release Microsphere Hydrogels Containing Leptin And VEGF In The Regulation Of Combined Radiation And Wound Injury

Objective:Combined radiation and wound injury(CRWI)is a term used to describe the combination of radiation injury and trauma.CRWI differs from other single or chronic hard-to-heal wounds in that the combination of radiation injury and trauma is the most prominent therapeutic challenge.The overall effectiveness of existing therapies is not satisfactory and the mechanism of action of most therapies is unclear.Therefore,there is a need to further improve existing therapies or propose new treatment modalities for CRWI to address the mechanisms of refractory healing.Studies have shown that both leptin(LP)and vascular endothelial growth factor(VEGF)have important applications in the repair of trauma and may have a targeted healing effect in the treatment of CRWI.However,in practice,the short half-life of LP and VEGF does not allow them to have a stable and long-lasting effect.To address this drawback,this study was conducted to examine the healing-promoting biological properties of sustained-release microsphere hydrogels containing Leptin and VEGF by establishing an in vitro radiation injury model,in order to provide new ideas for CRWI treatment.Methods:Sustained-release microsphere hydrogels containing Leptin and VEGF have been prepared in the laboratory.In this study,the biocompatibility of sustained-release microsphere hydrogels containing Leptin and VEGF was evaluated by measuring their proliferative activity using the CCK-8 method.The pro-healing effect of the sustainedrelease microsphere hydrogels containing Leptin and VEGF on CRWI was investigated in vitro using L929 and Raw264.7 cell lines: cells were subjected to ionising radiation and their proliferative activity was measured by the CCK-8 method;cellular reactive oxygen species(ROS)production was measured by the ROS kit;cell migration was measured by the cell scratch assay;and cell migration capacity was measured by the Calcein-AM/PI dual assay.The cell migration ability was measured by a cell scratch assay;apoptosis was measured by Calcein-AM/PI double staining;apoptosis and healing-related proteins Caspase-3,Caspase-9,Bcl-2 and MMP1 were measured by Western Blot in L929 cells.Results:1.Sustained-release microsphere hydrogels containing Leptin and VEGF has good biocompatibility.2.The in vitro radiation damage model was successfully established and the optimal drug loading concentration was determined: using a dose rate of 2.92 Gy/min and a total dose of 6 Gy as the ionizing radiation conditions,the optimal drug concentrations for the L929 cell experiment were VEGF 200 ng/ml and Leptin 200ng/ml,and the optimal drug concentrations for the Raw264.7 cell experiment were VEGF 50 ng/ml,Leptin 100 ng/ml.3.Sustained-release microsphere hydrogels containing Leptin and VEGF protected against the inhibitory effect of ionizing radiation on the proliferation of L929 and Raw264.7 cells.4.Sustained-release microsphere hydrogels containing Leptin and VEGF protected against the inhibitory effect of ionizing radiation on the migration of L929 cells.5.Sustained-release microsphere hydrogels containing Leptin and VEGF significantly alleviated the oxidative stress damage caused by ionizing radiation to L929 and Raw264.7 cells.6.Sustained-release microsphere hydrogels containing Leptin and VEGF alleviated apoptosis induced by ionizing radiation through Bcl-2 and Caspase-9/Caspase-3 pathways,and enhanced collagen deposition and promoted healing through upregulation of MMP-1 expression.Concluded:1.Sustained-release microsphere hydrogels containing Leptin and VEGF has good biocompatibility.2.Sustained-release microsphere hydrogels containing Leptin and VEGF can alleviate exenteration complex injury by inhibiting apoptosis,oxidative stress and promoting cell proliferation,migration and tissue healing.