Changes in biological behaviors of rat dermal f ibroblasts induced by high expression of MMP9

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 fi broblasts and affect wound healing is still unclear. The present study aimed to observe changes in the biological behaviors of rat dermal fi broblasts induced by high expression of MMP9 and to clarify the possible mechanisms of wound healing for diabetic foot.METHODS: A cell model of skin f ibroblast with high expression of MMP9 was established by coculture 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 transwell were used to detect cell proliferation, 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 signif icant.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, cell viability, 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 fi broblasts.

Correlation between Serum Level of Adiponectin and Severity of Coronary Artery Atherosclerosis

Objectives To investigate the correlation between serum level of adiponectin and severity of coronary artery atherosclerosis. Methods Coronary angiographies were performed and serum levels of adiponectin were measured in 88 patients with suspected coronary heart disease （CHD）. Patients were divided into groups according to the coronary angiographies and Gensini＇s scores of coronary artery atherosclerosis. The serum levels of adiponectin were compared in different groups, and multiple regressions were used to analyze the correlation factors of adiponectin. Results （1）Serum adiponectin concentration in CHD group [ 7. 1 mg/L （2.4 - 21.1 mg/L） ] was decreased as compared with that in control group [ 11.6 mg/L （4.4 - 28.2 mg/L ）, P 〈 0. 01 ] ; （2）The serum levels of adiponectin fell while the Gensini＇ s scores of coronary artery atherosclerosis increased （P 〈 0. 05, P 〈 0. 01 ） ; （3）Serum level of adiponectin was positively correlated with the high-density lipoprotein cholesterol, while negatively correlated with the Gensini＇ s score of coronary artery atherosclerosis and triglyceride （P 〈 0. 01 ）. Conclusions Serum adiponectin concentration was decreased in patients with CHD. Low serum levels of adiponectin reflected the severity of coronary artery atherosclerosis. Adiponectin was a protective factor of cardiovascular system.