Objective To evaluate the therapeutic effect of poloxamer hydrogel loaded with exosomes derived from human dental pulp stem cells genetically modified with human hepatocyte growth factor against radiation skin injuries.Methods Human dental pulp stem cells derived exosomes(DPSC-Exo)and hepatocyte growth factor modified DPSC-Exo(HGF-DPSC-Exo)were extracted via ultracentrifugation separation,identified in terms of particle size and morphology,and analyzed separately by means of nanoparticle tracking analysis and scanning electron microscopy(SEM),while exosome marker proteins were determined by Western blot.Then,the effect of exosomes on radiation-damaged skin cells was assessed.The poloxamer hydrogel was prepared and its safety was evaluated with CCK-8.A mouse model of injury combined with radiation injury was established,and the therapeutic effect of hydrogel loaded with exosomes was determined based on wound size,HE and Masson staining.Furthermore,the underlining therapeutic mechanism was explored with Tunnel assay,malondialdehyde content and peroxidase activity.Results The diameter exosomes ranged from 30 to 150 nm and their morphology was a disc-shaped vesicle under SEM.Moreover,CD9,CD63 and TSG101 were expressed.The results of cellular experiments showed that exosomes significantly promoted the proliferation and migration of radiation-damaged skin keratinocytes and fibroblasts,and reduced their apoptosis.HGF modification enhanced the healing effect of exosomes.Poloxamer hydrogel showed good temperature-sensitive properties and biocompatibility.The results of animal experiments showed that exosomes significantly accelerated the healing of radiation-combined injuries in mice,inhibited inflammatory infiltration and mitigated collagen deposition in the wound.Interestingly,the healing effect in the group treated with hydrogel loaded with exosomes was the best.The underlining mechanism was possibly related to promotion of cell proliferation and inhibition of apoptosis and oxidative stress.Conclusion A novel poloxamer hydrogel loaded HGF-DPSC-Exo has been prepared and its therapeutic effect against radiation combined injury has been proved,thus providing a new strategy for the treatment of radiation skin injury in clinic.

According to the problems exist in the original ultrasound system, the study elaborates the design and application of the ultrasound audit workstation system, including the workflow, trace information recording, information management, audit data interaction, application effects, et al. This study points out that the system can optimize the ultrasound process, help to improve the quality and efficiency of ultrasound report audit as well as improve the efficiency of patients' ultrasound examination and medical treatment experience.
Humans ; Medical Audit