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Monitoring blood glucose level timely and accurately and management of glucose level is crucial for the treatment of diabetes and the prevention of diabetic complications. Glycated albumin is one of the important biomarker to evaluate the fluctuation of blood glucose level, which has been widely used in clinic. To understand the advantages and limitations of the glycated albumin in monitoring glucose level will contribute to its better application in clinic.
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Objective To determine levels of nuclear factor (NF)-κB, interleukin (IL)-10, and visfatin in adipocytes treated by different degrees of intermittent hypoxia (IH), and to investigate the mechanism of IH leading to insulin resistance (IR). Methods The cell model of intermittent hypoxia/re-oxygenation (IH/ROX) in obstructive sleep apnea (OSA) was established. Differentiation mature 3T3-L1 adipocytes, were randomly divided into 10 groups including four different-frequency intermittent hypoxia groups(IH1-4, fixed intermittent hypoxia scheme for 1.5%O2 45 s and then re-oxygen 21%O2 for 2 min 15 s, 4 min 15 s, 5 min 45 s and 8 min 45 s, 60 times circulation), and their normal oxygen control groups (SC1-4, instead each IH group 1.5%O2 to 21%O2, the rest groups were treated as same as IH group), continuous hypoxia group (CH, 10%O2 for 6 h) and normal oxygen control group (CC, 21%O2 for 6 h). ELISA method was used to determine the levels of IL-10 and visfatin in the supematant of adipocytes. Western blot method was used to determine the protein levels of NF-κB p65 and visfatin. Real-time PCR method was used to determine the mRNA levels of IL-10 and visfatin. Results The protein and mRNA expressions of IL-10 were significantly lower in IH group and CH group than those of control groups (P<0.01). The levels of NF-κB p65 protein were significantly increased in IH group and CH group than those of control group. The protein and mRNA expressions of visfatin were significantly higher in IH1, IH2 and CH groups than those of control group (P<0.01). Conclusion As a prominent feature of OSA pathophysiology, IH may take part in insulin resistance of OSA patients by abnormally secreting NF-κB, IL-10 and visfatin in adipocytes.
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Objective To observe the effects of berberine on inflammatory factors, adipokines and fatty acid metabo-lism in 3T3-L1 adipocytes, and to investigate the molecular mechanism underlying berberine’s role of improving insulin re-sistance. Methods mRNA level of inflammatory molecules, adipokines, key enzymes and protein in fatty acid metabolism in 3T3-L1 cells were determined by quantitative real time polymerase chain reaction (qRT-PCR) after cells were treated with different concentrations of berberine (0, 5, 10, 20, 40μmol/L) for 24 hours and with 10μmol/L berberine at different du-rations (0,4,8,24,48 h). These factors mainly included interleukin-6 (IL-6), tumor necrosis factor-α(TNF-α), leptin, adipo-nectin, visfatin, fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC), adipose triglyceride lipase (ATGL) and adipocyte fatty acid binding protein (AFABP). Results In 3T3-L1 adipocytes, transcription level of IL-6, TNF-α, leptin, FAS, AT-GL, AFABP reduced with addition of berberine dosage at 10~40μmol/L(P＜0.05)while visfatin mRNA level increased(P＜0.05)compared with the control group. No significant difference was found in expression of adiponectin(P>0.05). Tran-scription level of IL-6, TNF-α, leptin, AFABP, ATGL, FAS decreased with time after 10μmol/L berberine intervention (8-48 h) compared with the control group(P＜0.05). On the other hand, visfatin mRNA level increased(P＜0.05)compared with the control group. Adiponectin mRNA decreased only after cells were treated with berberine for 48 h(P＜0.05). No sig-nificant difference was found transcription of ACC between each groups treated with berberine(P > 0.05). Conclusion mRNA level of inflammatory factors, adipokines, key enzymes and protein in fatty acid metabolism in 3T3-L1 adipocytes can be affected by berberine and this effect depend on its dose and time . This might be the mechanisms underlying berber- ine to improve insulin resistance.
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Objective To establish homogeneous immunoassay for detecting serum cardiac troponin I (cTnI) by using light induced chemiluminescent immunoassay (LiCA). Methods Polyclonal antibodies of cTnI were coated on the receptor particles, monoclonal antibodies of cTnI were biotinylated, and the donor particles were coated with streptavidin, all of which were composed of LiCA reagents. The optimal test conditions and analytical performance of the detection method were studied. Results The method was rapid, sensitive, and detection time was 17.5 min.The analytical sensitivity was 0.045 ng/mL and the functional sensitivity was 0.053 ng/mL.The recovery rate was 104.96%-108.21%;The within-run and the between-run coefficients of variation were 3.88%-5.53%and 7.60%-8.75%, respectively. The interference rates for the endogenous substances were less than 10%. The reference value of cTnI was less than 1.05 ng/mL;Results of cTnI LiCA correlated well with direct chemiluminescence detection (r2 =0.979). Conclusions This approach can be used for the quantitative detection of serum cTnI, and it is homogeneous and is free of clean separation. It provides a convenient, highly sensitive detection platform for clinical practice.
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Objective To study the mechanism of insulin-stimulated glucose uptake in skeletal muscle cells. Methods The responses of GluT4 translocation and glucose uptake to the investigational drugs of SB203580 and Wortmannin as well as the effect of insulin on the drugs during differentiation were detected to study the insulin signal pathway. Results The GluT4 translocation and glucose transport were increased under insulin stimulation by 2.5±0.2 and 2.2±0.1 folds, respectively while compared with control; but t1/2 were 3.3 min and 6.0 min, and IC50 to wortmannin were 43 nmol/L and 3 nmol/L respectively.SB203580 inhibited 64% and 62% of insulin-stimulated glucose uptake and photolabelling of cell surface GluT4, respectively, but had no effect on GluT4 translocation.The fold increase of insulin-stimulated glucose uptake (1.7±0.1 fold vs control)was lower than that of GluT4 translocation (2.3±0.1 fold vs control) in myoblasts. Conclusions In skeletal muscle cells, two insulin signal pathways mediate GluT4 translocation and activation of GluT4, respectively.Insulin engages both of the pathways to stimulate the cells for maximum glucose uptake.