Objective To investigate the effects of cinnamic aldehyde(CA)on Bcl-2-associated X protein(Bax)and Bcl-2 homologous antagonist/killer(Bak)in vascular endothelial cells of diabetic ulcer wound tissues,as well as on cell apoptosis.Methods ① Forty-eight healthy SPF-grade male SD rats(5 weeks old,weighing 180～220 g)were randomly assigned to a control group(12 rats)and a diabetes group(36 rats).The diabetic model was established with an intraperitoneal injection of 50 mg/kg STZ-citrate sodium solution and high-fat diet feeding.The diabetes group was further randomly divided into Model group,CA group,and the rb-bFGF group,with 12 animals in each group.Wounds in the Con and Model groups were disinfected and topically treated with normal saline,CA group received topical application of 4 μmol/L CA in PEG 400 gel,and those of the rb-bFGF group were treated with bevacizumab gel.The wound healing rate of each group was calculated at 3,7 and 14 d after intervention.At 14 d after intervention,pathological changes in the wounds were observed with HE staining,and the expression levels of Bax and Bak were detected by Western blotting.② Human umbilical vein endothelial cell line EA.hy926 was treated with 175 mmol/L glucose for 48 h to establish a cell model of high glucose injury.The experimental cells were divided into control group,model group and CA treatment group.Cell scratch test and tube formation test were performed respectively to determine the migration ability and angiogenesis of the cells.The expression levels of Bax and Bak was detected with immunofluorescence assay,and cell apoptosis was detected by TUNEL staining.Results ①The diabetic rats in the Model group exhibited significantly higher blood glucose level(P<0.05),declined wound healing rate at 7 and 14 d after intervention(P<0.05),and enhanced expression levels of Bax and Bak(P<0.05)when compared with the control group.Pathological observation revealed that,at 14 d after intervention,accompanied with inflammatory reactions,dense infiltration of inflammatory cells,fewer new blood vessels,and continuous fluid exudation in the wound were observed in the Model group,but the control group presented complete epithelialization in full-thickness skin.Compared with the conditions in the Model group,both CA and rb-bFGF treatment improved the epithelialization process,with mature granulation tissues,showing good healing condition,promoted wound healing rate(P<0.05),and decreased the expression levels of Bax and Bak(P<0.05).② The results of cell experiments showed that the cells of the model group showed significantly reduced migration ability and tube formation ability(P<0.05),reduced protein levels of Bax and Bak(P<0.05),and lower apoptotic rate(P<0.05)when compared with the cells in the model group.Conclusion CA can inhibit the expression of apoptosis-related proteins Bax and Bak,promote the migration and tube formation of vascular endothelial cells,and inhibit the cell apoptosis under high glucose condition,which may be an important reason for its promoting wound healing in diabetic ulcer rats.

Objective:To understand the molecular characteristics of Escherichia coli producing Shiga toxin 2e subtype isolated from different sources in China. Methods:Three human-derived, 13 animal-derived and eight food-derived stx2e-positive Escherichia coli strains which were isolated during 2012 to 2018 were analyzed by antimicrobial susceptibility testing and whole genome sequencing. The stx subtype, serotype, multi-locus sequence type, virulence genes and antimicrobial resistance genes of each strain were determined by whole genome sequences. The phylogenetic relationship and genetic composition of Shiga-toxin prophage were explored. Results:Twenty-four stx2e-STEC strains were typed into 19 O∶H serotypes and 19 sequence types (STs). Each strain carried at least one kind of antimicrobial resistance gene and 19 out of 24 strains were resistant to at least one kind of antimicrobials. Three human-derived strains were heterogenous in serotypes and STs, but there were several animal and food-derived strains shared the same serotype or ST with human strains and showed close relationship in the phylogenetic analysis. The sequences of stx2e among all strains were highly conserved (similarity >99.7%), but there were significant differences in the size and the gene composition of Shiga toxin prophage genome. Conclusions:This is report about the characteristics of rare human-derived Stx2e-STEC strains in China. Comparing human isolates with animal-and food-derived strains, it indicates that Stx2e-STEC strains are highly genetic diversity and have the potential to infect humans.