RESUMO
Background Studies showed that inflammatory process participates in the pathogenesis anddevelopment of diabetic retinopathy targeting retinal vascular endothelial cells (RVECs).A growing body of evidence revealed that metformin reduces the risk of micro-and macro-vascular complications by protecting blood-brain barrier,however,whether it plays a protective effect on human retinal vascular by similar mechanism is still unelucidated.Objective This study was to investigate the effects of metformin on the proliferation,migration and secreting monocyte chemotactic protein-1 (MCP-1) and interleukin-8 (IL-8) of human retinal vascular endothelial cells (RVECs) under the stimulation of tumor necrosis factor-alpha (TNF-α).Methods RVECs were cultured and divided into normal control group,metformin (5 mmol/L) group,TNF-α 2.5 ng/ml group,and TNF-α+metformin (5,10,20 and 40 mmol/L,respectively) groups.Corresponding drugs were added into medium according to grouping for 24 hours.Cell numbers were calculated before and after treatment.The metabolic activity (absorbancy) of RVECs was measured with MTS assay.Cell migration of RVECs was assessed with transwell migration assay.The MCP-1 and IL-8 concentrations in the cell supernatant were detected by ELISA assay.Results The number of the cells was significantly different among the normal control group,metformin group,TNF-α group,and TNF-α+metformin (5,10,20 and 40 mmol/L,respectively) groups (F =189.31,P ＜ 0.01).The metabolic activities of RVECs were 0.32 + 0.02,0.32±0.03,0.97 ± 0.02,0.90 ± 0.05,0.76 ± 0.15,0.74 ± 0.05 and 0.41 ± 0.03;migrated cell numbers were (1 214±49),(1 200±45),(1 648±43),(1 309±48),(1 279±73),(961±60) and (942±106)/field;the concentrations of MCP-1 were (0.385 ±0.050),(0.362±0.060),(2.285 ±0.200),(1.131 ±0.180),(0.622 ± 0.120),(0.537±0.090) and (0.492±0.130) μg/ml,and those of IL-8 were (0.385±0.080),(0.390±0.120),(1.123±0.130),(0.899±0.180),(0.680±0.060),(0.417±0.090) and (0.335±0.100) μg/ml in the normal control group,metformin group,TNF-α group,and TNF-α + metformin (5,10,20 and 40 mmol/L,respectively) groups,showing significant differences among the groups (F =73.31,103.89,150.92,268.32,all at P＜ 0.01).The cell number,cell metabolic activity,migrated cell number,and MCP-1 and IL-8 levels in the cell supernatant were evidently increased in the TNF-α group compared with the normal control group,and those in the TNF-α+10 mmol/L metformin group,TNF-e +20 mmol/L metformin group and TNF-α+40 mmol/L metformin group were significantly decreased in comparison with the TNF-α group (all at P＜0.05).Conclusions Metformin can inhibit TNF-α-induced proliferation,migration and MCP-1 and IL-8 secretion of the cells,and therefore plays a protective role on RVECs in the inflammatory environment.
RESUMO
Objective To explore the effect of mefformin on glucose metabolism of rat myoblast with high fat environment.Methods The skeletal muscles of suckling Wister rats were subjected to primary culture.The myoblasts of passage 5 were divided into 5 groups:The control group was cultured in DMEM with 0.5％ BSA for 12 h.The high-fat group was exposed to 0.3 mmol/L palmitic acid for 12 h.On the basis of high-fat treatment,three intervention groups were added with 2.5,5.0 and 7.5 μg/ml metformin,respectively,for additional 24 h.Isotope tracer method was conducted to show the influence on 2-dexoy-D-[3H]glucose uptake of rat myoblast.Results With the increasing concentration of mefformin,[3H]-G uptake elevated [ ( 1.83 ± 0.34) 10-2pmd/( min · g) vs (2.33 ± 0.47 ) 10-2 pmd/( min · g),P ＜ 0.05 ],and the group of 7.5 μg/ml metformin uptakes the most.Conclusions Metformin can upregulate the glucose-uptake in rat myoblasts under the environment of high fat,and it shows a dose-dependent relationship.