BACKGROUND:The study of deer antler stem cells and exosomes to promote the repair of acute skin injuries has received increasing attention in recent years,but the effect and mechanism of exosomes composite hydrogel to promote the repair of burn wounds are still unclear.OBJECTIVE:To investigate the effect of deer antler stem cell exosome composite hydrogel on the healing speed and quality of rat deep third-degree burn wound and its mechanism of action.METHODS:Deer antler stem cell exosomes and bone marrow mesenchymal stem cell exosomes were extracted and compounded with Pluronic F-127 to prepare a temperature-sensitive hydrogel.A constant temperature and pressure burn apparatus was used to prepare a rat model of deep third-degree burn.The drug was administered to four groups:deer antler stem cell exosome composite hydrogel group,bone marrow mesenchymal stem cell exosome composite hydrogel group,human epidermal growth factor gel group,and the control group.The healing of burned rats was observed and the wound healing rate was calculated.At 28 days after burn,hematoxylin-eosin staining was used to observe the generation of skin accessory structures in the healing tissues.Masson staining was used to analyze the accumulation of collagen in the healing tissues.Immunohistochemistry was used to examine the angiogenesis and nflammatory response in the healing tissues.qRT-PCR was used to examine the expression level of mRNA of the wound healing-related genes in the healing tissues.RESULTS AND CONCLUSION:(1)Deer antler stem cell exosome composite hydrogel can significantly promote the healing rate of deep burn wounds in rats,and improve the quality of wound healing by promoting the regeneration of skin collateral structures,increasing the dermal thickness and enhancing the accumulation of collagen.(2)The number of myofibroblasts in the wound healing tissues of deer antler stem cell exosome composite hydrogel group was significantly reduced,and the number of neovascularization and M2 macrophages was significantly increased.(3)The mRNA levels of transforming growth factor β3 and type Ⅲ collagen in the wound healing tissue of deer antler stem cell exosome composite hydrogel group were significantly higher than those of the blank group,and the mRNA levels of transforming growth factor β1,matrix metalloproteinase 3,and type Ⅰ collagen were significantly lower than those of the blank group,and there was no significant difference between the bone marrow-derived mesenchymal stem cell exosome composite hydrogel group and the human epidermal growth factor gel group.In conclusion,deer antler stem cell exosome composite hydrogel can promote the healing speed and the quality of healing of deep burned wounds in rats,which may be achieved by inhibiting fibroblastogenesis,promoting angiogenesis,macrophage M2 polarization,and regulating the expression of genes for collagen production/degradation.

BACKGROUND:The study of deer antler stem cells and exosomes to promote the repair of acute skin injuries has received increasing attention in recent years,but the effect and mechanism of exosomes composite hydrogel to promote the repair of burn wounds are still unclear.OBJECTIVE:To investigate the effect of deer antler stem cell exosome composite hydrogel on the healing speed and quality of rat deep third-degree burn wound and its mechanism of action.METHODS:Deer antler stem cell exosomes and bone marrow mesenchymal stem cell exosomes were extracted and compounded with Pluronic F-127 to prepare a temperature-sensitive hydrogel.A constant temperature and pressure burn apparatus was used to prepare a rat model of deep third-degree burn.The drug was administered to four groups:deer antler stem cell exosome composite hydrogel group,bone marrow mesenchymal stem cell exosome composite hydrogel group,human epidermal growth factor gel group,and the control group.The healing of burned rats was observed and the wound healing rate was calculated.At 28 days after burn,hematoxylin-eosin staining was used to observe the generation of skin accessory structures in the healing tissues.Masson staining was used to analyze the accumulation of collagen in the healing tissues.Immunohistochemistry was used to examine the angiogenesis and nflammatory response in the healing tissues.qRT-PCR was used to examine the expression level of mRNA of the wound healing-related genes in the healing tissues.RESULTS AND CONCLUSION:(1)Deer antler stem cell exosome composite hydrogel can significantly promote the healing rate of deep burn wounds in rats,and improve the quality of wound healing by promoting the regeneration of skin collateral structures,increasing the dermal thickness and enhancing the accumulation of collagen.(2)The number of myofibroblasts in the wound healing tissues of deer antler stem cell exosome composite hydrogel group was significantly reduced,and the number of neovascularization and M2 macrophages was significantly increased.(3)The mRNA levels of transforming growth factor β3 and type Ⅲ collagen in the wound healing tissue of deer antler stem cell exosome composite hydrogel group were significantly higher than those of the blank group,and the mRNA levels of transforming growth factor β1,matrix metalloproteinase 3,and type Ⅰ collagen were significantly lower than those of the blank group,and there was no significant difference between the bone marrow-derived mesenchymal stem cell exosome composite hydrogel group and the human epidermal growth factor gel group.In conclusion,deer antler stem cell exosome composite hydrogel can promote the healing speed and the quality of healing of deep burned wounds in rats,which may be achieved by inhibiting fibroblastogenesis,promoting angiogenesis,macrophage M2 polarization,and regulating the expression of genes for collagen production/degradation.

The aim of this study was to construct a mammary gland-specific expressional vector pBC1-hLF-Neo for Human Lactoferrin (hLF) gene and then investigate its expression in the mammary gland epithelium cells. The constructed vector contained the 6.2 kb long 5' flank regulation region including promoter, other elements and the 7.1 kb long 3' flank regulation region including transcriptional ending signal of a goat's beta-casein gene. A cassette of Neo gene was also inserted into the vector which gave a total length of 26.736 kb identified by restriction fragment analysis and partial DNA sequencing. The results revealed that the structure of the final constructed vector accords with the designed plasmid map. In order to analyze the bioactivity of the vector, we transfected the lined vector DNA into the dairy goat's mammary gland epithelium cells and C127 cells of a mouse's mammary epithelium by Lipofectamine. After selection with G418 for 8-10 days, G418-risistant clones were obtained. PCR analysis demonstrated that hLF gene cassette had been integrated into the genomic DNA of G418-risistant clones. After proliferation culture, the two kinds of transgenic cells were cultured in serum-free DMEM-F12 medium with prolactin, insulin and hydrocortisone- a medium capable of inducing recombinant hLF expression. RT-PCR, Western blotting and anti-bacteria bioactivity experiments demonstrated that the constructed mammary gland specific vector pBC1-hLF-Neo possessed the desirable bioactivity to efficiently express and could secrete hLF in both mammary gland cells and have the effect of E. coli proliferation inhibition. Paramount to everything, this study laid a firm foundation for preparing the hLF gene transgenic goat fetal-derived fibroblast cells.
Animals ; Base Sequence ; Breast Neoplasms ; metabolism ; pathology ; Caseins ; genetics ; Cell Line, Tumor ; DNA, Complementary ; biosynthesis ; genetics ; Epithelial Cells ; metabolism ; Female ; Genetic Vectors ; genetics ; Goats ; Humans ; Lactoferrin ; biosynthesis ; genetics ; Mammary Glands, Animal ; cytology ; metabolism ; Mice ; Molecular Sequence Data ; Mutagenesis, Insertional ; Promoter Regions, Genetic ; genetics