| Part I The expression levels of serum interleukin-17 in type 2 diabetes with macroangiopathy[Abstract] Objective To study the expression levels of serum IL-17 in type 2 diabetes mellitus (T2DM) with macroangiopathy, and to carry out the correlation analysis between these two factors. Methods A total of 162 patients diagnosed of T2DM were divided into two groups according to the macrovascular complications, 90 cases with macroangiopathy and 72 cases without macroangiopathy, another 68 healthy persons were enrolled in the control group. Serum inflammatory cytokines, such as IL-17, were measured by using enzyme linked immunosorbent assay (ELISA), the relationship between IL-17 and other impact factors was statistically ananlyzed. Meanwhile, according to the presence or absence of the thickening of carotid intima-media thickness (IMT), part of the patients with T2DM were then assigned into another two groups to compare the related indicators. Results The levels of serum IL-17, IL-23, IL-1β in T2DM with and without macroangiopathy groups were significantly higher than control group, and the differences from those of T2DM groups were also statistically significant (P<0.05). IL-17 and IL-6 levels in T2DM with carotid thickening group were largely increased when compared with non-thickening group (P<0.05). In T2DM with macroangiopathy group, IL-17 was positively correlated with BMI,2hPG, hs-CRP, TG, IL-23, IL-6, IL-1β and negatively correlated with HDL-C, IL-10. Stepwise regression analysis showed that IL-17, hs-CRP and HDL-C were the main factors for T2DM macroangiopathy, and there was a linear relationship between IL-17 and IL-23, TG and HDL-C. Conclusion T2DM macroangiopathy group and carotid thickening group serum IL-17 expression levels were elevated, suggesting that IL-17 may be involved in the process of inflammatory response to diabetic macroangiopathy. IL-17 may be an independent risk factor for T2DM macroangiopathy, and may play a vital role in the onset and development diabetic vascular diseases via IL-23 inflammatory signaling pathway and TG, HDL-C changes.Part Ⅱ Expression of interleukin-17 in diabetic macroangiopathy and the mechanisms of intervention with resveratrol[Abstract] Objective To study the expression of interleukin-17 (IL-17) in diabetic rats aorta and the effect of intervention with resveratrol, meanwhile, to explore the potential mechanisms of IL-17 induced diabetic vascular diseases and the protective role played by resveratrol in the epigenetic field. Methods The experiment was carried out in 4 groups:normal control group (NC), normal interventional group (NB), diabetic group (DM), and diabetic interventional group (DB), NB and DB groups were intervened with resveratrol. Immunohistochemistry was used to observe the histological localization of IL-17 and to measure the thickness of rat abdominal aorta. Western blotting, real-time PCR and methylation-specific PCR were used to respectively compare the expression of IL-17 protein and mRNA as well as DNA methylation in 4 groups. Results IL-17 mainly expressed in arterial intima of diabetic rats, the abdominal aorta in DM group was obviously thicker than that in NC and DB groups (P<0.05). IL-17 protein and mRNA expressions in DM group were significantly higher than NC group (P<0.05), and were reduced in NB and DB groups compared with NC and DM groups respectively. While DNA methylation levels of IL-17 in DM group were significantly lower than NC group (P<0.01), however, the levels in NB and DB groups were elevated accordingly as compared with corresponding groups. Conclusion The increased levels of IL-17 in aorta of diabetic rats suggested that IL-17 was involved in the process of inflammatory responses to diabetic macrovascular diseases, while resveratrol could inhibit the expression, it may play a role in protecting on aortas, and regulation of IL-17 gene promoter DNA methylation levels may be the potential mechanism underlying these two phenomena.Part III Effects of Resveratrol on the Expression and DNA Methylation of Cytokine Genes in Diabetic Rat Aortas[Abstract] Objective To study the expression of proinflammatory cytokines such as IL-1β, IL-6, TNF-α, and IFN-γ and anti-inflammatory cytokines such as IL-10 in diabetic rat aortas, the effects of resveratrol on these cytokines, and the potential epigenetic mechanisms involved. Methods The experiment was performed on rats divided into four groups:normal group (NC), normal interventional group (NB), diabetic group (DM), and diabetic interventional group (DB). The NB and DB groups were treated with resveratrol. After more than three months, the rats’aortas were removed and analyzed for cytokines by using immunohistochemistry, Western blotting, real-time PCR, and methylation-specific PCR. Results Histological localization of these cytokines was mainly found in the arterial intima of diabetic rats. The protein and mRNA expression levels of IL-1β, IL-6, TNF-α, and IFN-γ were significantly higher in the DM group than in the NC group (P<0.05), whereas in the resveratrol-treated groups (NB and DB), the levels were relatively lower than those in the corresponding groups. The DM group showed reduced levels of DNA methylation at the specific cytosine phosphate guanosine sites of IL-1β, IL-6, TNF-a, and IFN-y, relative to those in the NC group (P<0.01), and these levels were increased by resveratrol. In contrast, IL-10 was dramatically methylated and showed decreased expression in response to high glucose, and resveratrol reversed this effect.Conclusions These results demonstrate that the inflammatory response is involved in diabetic macroangiopathy. Resveratrol inhibits the expression of proinflammatory cytokines and thus may have a protective effect on the aorta in hyperglycemia. Thus, DNA methylation, an epigenetic gene silencing signal, may be responsible for these two phenomena. |
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