ABSTRACT
BACKGROUND:The high level of matrix metalloproteinase 9 (MMP9) is thought to slow down the healing of diabetic foot ulcers. Whether it can influence the biological behaviors of skin fibroblasts and affect wound healing is stillunclear. The present study aimed to observe changes in the biological behaviors of rat dermal fibroblasts induced by high expression of MMP9 and to clarify the possible mechanisms of wound healing for diabetic foot. METHODS:A cellmodel of skin fibroblast with high expression of MMP9 was established by co-culture of high glucose (22.0 mmol/L) and homocysteine (100 μmol/L). A control group was incubated with normal glucose (5.5 mmol/L). Realtime PCR, ELISA and gelatin zymography were used to detect the MMP9 mRNA, protein expression and activity of MMP9. Flow cytometry, CCK-8, ELISA assay, scratch test and transwellwere used to detect cellproliferation, viability, collagen (hydroxyproline) secretion, horizontal migration and vertical migration of cells. The data were expressed as mean±SD. P value less than 0.05 was considered statistically significant. RESULTS:The expression of MMP9 mRNA, protein levels and the activity of MMP9 were much higher in the high MMP9 group than in the control group (7.05±1.02 vs. 1.00±0.00, 206.9±33.6 pg/mL vs. 40.4±5.9 pg/mL, and 1.47±0.13 vs. 0.57±0.12, respectively,P<0.01). The proportion of S-phase cells, proliferation index, cellviability, collagen (hydroxyproline) secretion, horizontal migration rate and the number of vertical migration cells were lower in the high MMP9 group than in the control group (P<0.01). CONCLUSION:Fibroblasts with a high expression of MMP9 decreased proliferation, activity, secretion and migration of collagens, suggesting that MMP9 may inhibit the biological behaviors of fibroblasts.
ABSTRACT
Objective To induce mouse embryonic stem(ES)cells to differentiate into insulin-secreting cells by means of a 5-step model system.Methods E14.1 mouse ES cells were cultured in the presence of leukemia inhibitory factor(LIF)for 2 days(step 1),then the cells were cultured in hanging drops to form embryonic bodies(EBs)and the resulting EBs were cultured in suspension for 6 days in the presence of basic fibroblast growth factor bFGF(step 2).Subsequently the EBs were cultured in the medium containing glucagon- like peptide 1(GLP-1),hepatocyte growth factor(HGF),nerve growth factor(NGF)and nicotinamide for 10 days(step 3).After that,the EBs were dissociated into single cells,and the cells were cultured in monolayer in the presence of GLP-1,betacellulin,activin A,bFGF and nicotinamide for 10 days(step 4).Finally,the cells were cultured in low-glucose medium containing nicotinamide for 4 days(step 5).Insulin and some other islet- related genes expressions were investigated using RT-PCR and insulin expression was also investigated by DTZ- staining and immunohistochemistry.The percentage of insulin-secreting cells was evaluated by flowcytometry and insulin concentrations were measured by RIA.Results mRNA expression of insulin became visible at step 3 and more evident at step 5.Additionally,at step 5,mRNAs of glucagon,somatostatin,pancreatic polypeptide(PP), pancreatic duodenal homeobox 1(PDX-1),beta-cell E box transactivator 2(Beta2)and neurogenin 3(Ngn3) were detected.DTZ-staining positive cells and insulin immunohistochemical staining positive cells were observed. The percentage of insulin-positive cells was(24.0?2.5)%(n=6).In the presence of 5.6 mmol/L and 25 mmol/L glucose,insulin concentrations were(0.05?0.01)?g/L and(0.13?0.02)?g/L respectively(n= 6).Conclusion E14.1 mouse ES cells can be induced to differentiate into insulin-secreting cells by the 5-step model system.Insulin-secreting cells can release insulin into culture medium when treated with glucose,and insulin concentrations increase with rising concentration of glucose.