O-linked N-acetylglucosamine (O-GlcNAc) glycosylation is an important form of post-translational protein modification, mainly intracellular. It is closely related to cellular signaling pathways, and is involved in signal transduction, gene transcription and other important biological processes. Studies have found that O-GlcNAc glycosylation is directly related with diabetic retinopathy (DR), further studies may help us to uncover the DR mechanism, and develop new strategies for the diagnosis and treatment of this disease.
Objective To study the expression of receptor of advanced glycation end products (RAGE) in autogenous vein graft of streptozotocin induced diabetic rats and the inhibitory effects of aminoguanidine on intimal hyperplasia. Methods Sixty male Sprague-Dawley rats were randomly divided into three groups: aminoguanidine group, distilled water group and control group. Autogenous vein graft models were established in all groups. Streptozotocin was injected into abdominal cavity to induce diabetes in both aminoguanidine group and distilled water group, and they were intragastric administrated with aminoguanidine or distilled water, respectively before and after transplantation. Specimens were collected from autogenous vein graft 7 days and 14 days after surgery to undergo histological examination. At the same time, the level of serum advanced glycation end products (AGE) was tested. Western blotting and immunohistochemistry were used to detect the protein expression of RAGE and NF-κB p65. RAGE and NF-κB p65 mRNA were measured by reverse transcription-PCR. Results The mRNA and protein expressions of RAGE, NF-κB p65, the level of serum AGE and the intimal thickness of vein graft in distilled water group increased in comparison with those in control group 7 days and 14 days after surgery （P＜0.05). The level of serum AGE, mRNA and protein expressions of NF-κB p65 and the intimal thickness of vein graft in aminoguanidine group were lower than those in distilled water group （P＜0.05), and showed no significant difference compared with control group （P＞0.05). Conclusion The over-expression of RAGE in vein graft activats NF-κB in streptozotocin-induced diabetic rat, which has a close relation with intimal hyperplasia. Aminoguanidine can block the binding of AGE and RAGE by inhibiting the production of AGE, which will prevent intimal hyperplasia of vein graft.
Objective To study the effects of advanced glycation end (AGEs) products induced by bovine serum albumin (BSA) on the survival and the morphology of bovine retinal endothelial cells (BREC) and pericytes (BRP). Methods BSA with the final concentration of 50 mg/ml was incubated in PBS, containing 500 mmol/L D-glucose, for 12 weeks under 37℃. AGEs-BSA was purified by Sephacryl S-300 column chromatography and was confirmed by sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE). The concentration of AGEs-BSA was determined by the method of commassie protein assay. In order to detect the toxic effects of AGEs-BSA on cultured BREC and BRP, groups of AGEs-BSA and BSA with different concentration and untreated control were set up. Phase contrast microscope was used to observe the effect of AGEs-BSA and BSA (with the concentration of 500mu;g/ml and actuation duration of 48 hours) on morphology of BREC and BRP. Results As the dosage of AGEs-BSA increased, the number of inhibited cells increased. When the concentration of AGEs-BSA was 500mu;g/ml, the inhibited BREC in AGEs-BSA group was (72.8plusmn;15.9)% of which in untreated control group, and the inhibited BRP was (64.8plusmn;9) % of which in untreated control group. AGEs-BSA with low concentration promoted the proliferation of endothelial cells, but there was no significant difference between AGEs-BSA and the control group (P=0.231). Inhibited proliferation and abnormal morphology were seen under the phase contrast microscope while the normal morphology of cells was found in BSA and control group. Conclusion AGEs-BSA with the high concentration may inhibit the growth of both BREC and BRP, which leads the loss of BRP and damage of vascular function. These results suggest that nonenzymatic glycosylation plays a major role in diabetic complications. (Chin J Ocul Fundus Dis, 2006, 22: 11-15)
Objective To investigate the effects of advanced glycation endproducts (AGEs) on proliferation of pericytes of bovine retinal capillary vessels and expression of transforming growth factor beta;(TGF-beta;). Methods The proliferation of pericytes detected by methyl thiazolyl tetrazolium (MTT) colorimetric assay, cellular cycle of pericytes was analyzed by flow cytometry was used to analyze cell, and TGF-beta; protein expression of pericytes was observed by immunofluorescent staining. Results AGEs inhibited the proliferation of pericytes of bovine retinal capillary vessels, stopped the cellular cycle of pericytes in synthesis phase (S phase), increased the number of apoptotic cells obviously (Plt;0.01), and promoted the expression of TGF-beta; proteinof perycytes. Conclusions AGEs may promote the apoptosis of pericytes by inhibiting the proliferation of pericytes to lead the decrease of pericytes number, and may accelerate diabetic retinopathy by promoting the expression of TGF-beta; protein of pericytes. (Chin J Ocul Fundus Dis, 2006, 22: 20-23)
Objective To investigate the effect of advanced glycation end products (AGEs) on the catalase activity and the levels of malondialdehyde in cultured bovine retinal capillary pericytes (BRPs), and to investigate the relationship between oxidative stress and diabetic retinopathy. Methods Cultured BRPs were exposed to AGEs (0, 8, 32, 125, 500, 2 000 μg/ml) for four days. Activity and the levels of catalase and malondialdehyde in cultured BRPs were examined by spectrophotometry. Results AGEs decreased the catalase activity, whereas increased the levels of malondialdehyde of cultured BRPs in a dose-dependent manner (r=-0.714, r=0.748, P＜0.01).There were significant differences between BRPs cultured in 32 μg/ml AGEs and in control group (P＜0.01), while no significant differences between BRPs cultured in non-glycated bovine serum albumin and absence of bovine serum albumin were found. Conclusion Oxidative stress may be one of the reasons why the pericyte disappears in diabetic retinopathy. (Chin J Ocul Fundus Dis, 2002, 18: 143-145)
ObjectiveTo observe and analyze the effect of HbA1c level on macular microcirculation in patients with type 2 diabetes mellitus (T2DM).MethodsA cross-sectional study. One hundred and twenty-four T2DM patients (124 eyes) without diabetic retinopathy who diagnosed by the examination of fundus color photography in Lixiang Eye Hospital Of Soochow University during September to December 2017 were enrolled in this study. There were 59 males (59 eyes) and 65 females (65 eyes), with the mean age of 65.06±7.99 years old. All patients underwent BCVA, fundus color photography, and OCT angiography (OCTA). The history of diabetes, hypertension and dyslipidemia were recorded in detail. According to the HbA1c level, patients were divided into three groups, HbA1c ideal control group (group A, HbA1c ＜7%, 67 eyes), HbA1c control group (group B, 7%≤HbA1c≤9%, 44 eyes), and HbA1c poor control group (group C, HbA1c＞9%, 13 eyes), respectively. The 3 mm×3 mm range of the macular area was scanned by OCTA instrument. The vascular density (VD) and skeleton density (SD) of nonsegmented retinal layer (NRL), superficial retinal layer (SRL) and deep retinal layer (DRL) in the macular area and foveal avascular zone (FAZ) area, non-circularity index, axial rate (AR) of SRL were measured. The correlation between HbA1c, BCVA and VD, SD of NRL, SRL, DRL was analyzed statistically with Spearman correlation test. The correlation between systemic factors and the above indicators was analyzed statistically with linear regression analysis.ResultsThe results of linear regression analysis showed that HbA1c was significantly correlated with VD (t=−3.237, −3.156, −2.050) and SD (t=−0.3.45, −3.034, −2.248) of NRL, SRL and DRL (P＜0.05); but no correlation with FAZ, non-circularity index and AR (t=1.739, 0.429, 1.155; P＞0.05). The differences of VD (F=6.349, 5.981, 3.709), SD (F=7.275, 6.085, 1.904) and AR (F=0.027) of NRL, SRL and DRL in group A, B and C were statistically significant (P＜0.05); but the differences of FAZ (F=1.904), non-circularity index (F=0.280) was not statistically significant (P＞0.05). Significant differences (P＜0.05) of VD and SD of NRL were found between group A and B (t=1.987, 2.201), group A and C (t=3.365, 3.572), group B and C (t=2.010, 2.076). Significant differences (P＜0.05) of VD and SD of SRL were found between group A and B (t=2.087, 2.168), group A and C (t=3.197, 3.194). There were significant differences (P＜0.05) in SD of DRL between group A and B (t=2.239), group A and C (t=−2.519). There was significant difference in VD of DRL between group A and C (t=2.363). The results of Spearman correlation analysis showed that HbA1c was negatively correlated with VD (r=−0.273, −0.255, −0.222; P=0.002, 0.004, 0.013) and SD (r=−0.275, −0.236, −0.254; P＜0.05) of NRL, SRL, DRL; positively correlated with FAZ and BCVA (r=0.221, 0.183; P＜0.05). BCVA was negatively correlated with VD (r=−0.210, −0.190, −0.245) and SD (r=−0.239, −0.207, −0.296) of NRL, SRL, and DRL (P＜0.05), but not correlated with FAZ (r=0.099, P＞0.05).ConclusionThe decrease of macular perfusion and the morphological change of FAZ accompanied by HbA1c increased.
ObjectiveTo observe the protective effect of tanshinone Ⅱ A on the mouse liver ischemia-reperfusion injury (IRI) model and preliminarily explore its mechanism of alleviating liver injury.MethodsThe IRI mouse model was established after the pre-treating with tanshinone Ⅱ A. Then, the serum and liver tissue of mice were collected to detect the changes of liver function, histopathology, liver cell apoptosis, and inflammatory factors. In addition, the protein expression levels of high mobility group box 1 (HMGB1), advanced glycosylation end-product specific receptor (RAGE), and Toll like receptor 4 (TLR4) in the liver tissues were detected by the Western blot method.ResultsAll data were analyzed by the homogeneity of variance test. The results of factorial design showed that the levels of ALT and AST in the serum, the pathological score and apoptosis index, the inflammatory response, as well as the expressions of HMGB1, TLR4 and RAGE proteins in the liver tissues were decreased significantly (P<0.05) in the sham operatation plus tanshinone Ⅱ A mice, which were increased significantly (P<0.05) in the IRI mice, which were antagonized synergistically by the tanshinone ⅡA and IRI (P<0.05).ConclusionsTanshinone ⅡA could reduce the liver IRI and inflammatory response in mouse. These effects might be related to the down-regulations of TLR4, HMGB1, and RAGE expressions.
【摘要】 目的 观察晚期糖基化终产物（advanced glycosylation end prodrcts，AGE）对人结肠癌细胞株SW-480增殖的影响，并探讨其可能机制。 方法 不同浓度AGE干预SW-480细胞，噻唑蓝（MTT）法比较各组细胞活力，流式细胞术观察AGE对SW-480细胞周期的影响，蛋白质印迹法观察AGE对SW-480细胞CyclinD1表达的影响，端粒重复序列扩增法（telomeric repeat amplification protocol，TRAP）银染法观察AGE对SW-480细胞端粒酶活性的影响。MTT测细胞活力的检测设置空白对照组、100 μg/mL小牛血清白蛋白（bovine serum albumin，BSA）组及50、100、500 μg/mL AGE组，其余检测只设置100 μg/mL BSA组和100 μg/mL AGE组。 结果 MTT结果示AGE促进SW-480细胞的增殖，且呈浓度依赖性。100 μg/mL BSA组与100 μg/mL AGE组72 h后的细胞G0/G1期所占百分比分别为56.02%±0.58%、51.93%±1.01%，差异有统计学意义（Plt;0.05）。蛋白质印迹法示100 μg/mL AGE组72 h后CyclinD1的表达较100 μg/mL BSA组增加，差异有统计学意义（Plt;0.05）。TRAP银染法检测示100 μg/mL AGE干预SW-480细胞72 h后可以增加端粒酶活性（Plt;0.05）。 结论 AGE可促进人结肠癌细胞SW-480生长，呈剂量依赖性。其作用机制可能与AGE上调CyclinD1的表达加速G1/S期转换及增加端粒酶活性有关。【Abstract】 Objective To observe the effects of advanced glycosylation end products (AGE) on proliferation of SW-480 cells and study the possible mechanism. Methods Various concentrations of AGE were designed to have impact on SW-480 cells. Proliferation of SW-480 cells was assessed by thiazolyl blue tetrazolium bromide (MTT) assay; The impact of AGE on the cell cycle of SW-480 cells was analyzed by flow cytometry (FCM); the influence of AGE on expression of CyclinD1 was checked by Western blotting; and the impact of AGE on telomerase activity was examined by telomeric repeat amplification proctol (TRAP) sliver staining. For the MTT assay, blank control group, 100 μg/mL bovine serum albumin (BSA) group, 50, 100 and 500 μg/mL AGE groups were designed, while for other examinations, there were only 100 μg/mL BSA group and 100 μg/mL AGE group. Results MTT result showed that AGE increased the proliferation of SW-480 cells in a dose-dependent mode. The proportion of the cells at G0/G1 stage of the 100 μg/mL BSA group and the 100 μg/mL AGE experimental group were (56.02±0.58)% and (51.93±1.01)% respectively after 72 hours, with a significant difference (Plt;0.05); western blotting showed that the expression of CyclinD1 in the 100 μg/mL AGE group was significantly higher than that in the 100 μg/mL BSA group after 72 hours; TRAP silver staining demonstrated that telomerase activity increased significantly after treated with 100 μg/mL AGE for 72 hours. Conclusions AGE can promote the growth of SW-480 cells in a dose-dependent mode. Its mechanism is mainly by up-regulating the expression of CyclinD1 to shorten G0/G1 and increasing the telomerase activity significantly.
Cell migration is defined as the directional movement of cells toward a specific chemical concentration gradient, which plays a crucial role in embryo development, wound healing and tumor metastasis. However, current research methods showed low flux and are only suitable for single-factor assessment, and it was difficult to comprehensively consider the effects of other parameters such as different concentration gradients on cell migration behavior. In this paper, a four-channel microfluidic chip was designed. Its characteristics were as follows: it relied on laminar flow and diffusion mechanisms to establish and maintain a concentration gradient; it was suitable for observation of cell migration in different concentration gradient environment under a single microscope field; four cell isolation zones (20 μm width) were integrated into the microfluidic device to calibrate the initial cell position, which ensured the accuracy of the experimental results. In particular, we used COMSOL Multiphysics software to simulate the structure of the chip, which demonstrated the necessity of designing S-shaped microchannel and horizontal pressure balance channel to maintain concentration gradient. Finally, neutrophils were incubated with advanced glycation end products (AGEs, 0, 0.2, 0.5, 1.0 μmol·L−1), which were closely related to diabetes mellitus and its complications. The migration behavior of incubated neutrophils was studied in the 100 nmol·L−1 of chemokine (N-formylmethionyl-leucyl-phenyl-alanine) concentration gradient. The results prove the reliability and practicability of the microfluidic chip.