OBJECTIVES: To investigate the mechanism by which chitosan (CS) hydrogel loaded with human umbilical cord mesenchymal stem cell (HUVECs)-derived exosomes (hUCMSC-exos) (Exos@CS-Gel) improves diabetic wound healing. METHODS: hUCMSC-exos were extracted and Exos@CS-Gel was prepared. The effect of Exos@CS-Gel on proliferation and migration of HUVECs were evaluated using scratch wound assay and CCK-8 assay. Diabetic rat models with full-thickness skin wounds established by streptozotocin induction were randomized divided into 4 groups for treatment with Exos@CS-Gel (100 µg hUCMSC-exos dissolved in 100 µL 24% CS hydrogel), hUCMSC-exos (100 µg hUCMSC-exos dissolved in 100 µL PBS), CS hydrogel (100 µL 24% CS hydrogel), or PBS (control group). Wound healing and the therapeutic mechanisms were assessed using immunohistochemistry, HE staining, immunofluorescence, and qRT-PCR. RESULTS: In cultured HUVECs, Exos@CS-Gel treatment significantly promoted cell proliferation and migration. In the rat models of chronic diabetic wounds, the wound healing rate in Exos@CS-Gel group reached 92.7% on day 14, significantly higher than those in hUCMSC-exos group (9.12%), CS hydrogel group (16.28%), and control group (25.98%). Microvessel density and the expression levels of vascular endothelial growth factor and transforming growth factor β-1 were significantly increased in the Exos@CS-Gel group. CONCLUSIONS Exos@CS-Gel promotes survival capacity of hUCMSC-exos in vitro and accelerates diabetic wound healing in rats by promoting angiogenesis and cell proliferation.
Animals ; Wound Healing ; Humans ; Chitosan ; Exosomes ; Mesenchymal Stem Cells/cytology* ; Diabetes Mellitus, Experimental ; Rats ; Umbilical Cord/cytology* ; Hydrogels ; Human Umbilical Vein Endothelial Cells ; Cell Proliferation ; Rats, Sprague-Dawley ; Male

OBJECTIVE：To investigate the potential mechanism of Salvia miltiorrhiza in the treatment of postoperative abdominal adhesion （PAA）. METHODS ：Active components and target genes of S. miltiorrhiza were retrieved from TCMSP database，SwissADME database ，Perl database ，UniProt database and other databases. GeneCards ，OMIM and PubMed database were used to retrieve target genes related to PAA. Venn diagram was drawn by using mapping tool of bioinformatic online database so as to screen the intersecting targets of active component-PAA. STRING platform was adopted to establish target network related to active component-PAA and protein-protein interaction （PPI）network of intersecting targets ，etc.，and to screen hub genes. Gene ontology（GO）and Kyoto Encyclopedia of Genes and Genom es（KEGG）pathway enrichment were carried out by using R 3.6.1 software. Using the protein encoded by hub gene as receptor and tanshinone Ⅱ A as ligand ，the molecular docking was carried out with AutoDock 1.5.6 tool. RESULTS ：A total of 38 active components of S. miltiorrhiza with high gastrointestinal absorption and their corresponding 72 targets，755 PAA-related target genes were identified. Results of Venn diagram showed that there were 33 intersecting targets of active components of chuqi90@163.com S. miltiorrhiza with PAA. Tanshinone ⅡA，dihydrotanshinolac- tone and other components may be important nodes of the target network related to active component-PAA. FOS，APP，ACHE， CASP3 and PTGS2 may be the hub genes in PPI network of intersecting targets. Results of GO enrichment showed that the intersecting targets were mainly concentrated in adrenergic receptor activity ，catecholamine binding ，G protein-coupled amine receptor activity and so on ；KEGG pathway enrichment analysis showed that the intersecting targets were mainly enriched in neuroactive ligand-receptor interaction ，cGMP-PKG signaling pathway ，endocrine resistance ，EGFR-tyrosine kinase inhibitor resistance and calcium signaling pathway.Molecular docking analysis showed that tanshinone ⅡA could form hydrogen bonds with many amino acid residues such as VAL- 580 of proto oncogenes c-Fos ，amyloid precursor protein ，acetylcholinesterase，caspase 3 and prostaglandin G/H synthase 2. CONCLUSIONS ：The active components of S. miltiorrhiza play a role in the treatment of PAA by directly or indirectly acting on neuroactive ligand-receptor interaction ，cGMP-PKG signaling pathway ，endocrine resistance ， EGFR-tyrosine kinase inhibitor resistance resistance and calcium signaling pathway.