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Objective: To investigate the impact and related mechanisms of glucose fluctuations on aortic fibrosis in rats with type 1 diabetes mellitus. Methods: After injection of streptozotocin (STZ), male Sprague Dawley (SD) (8-12 weeks) rats (n=24) were randomly divided into three groups in accordance with the random number table: controlled STZ-induced diabetes (C-STZ) group (n=8); uncontrolled STZ-induced diabetes (U-STZ) group (n=8); STZ-induced diabetes with glucose fluctuations (STZ-GF) group (n=8). After three weeks, rats were sacrificed and aorta was obtained, aortic fibrosis was detected by Masson trichrome staining. The expression of collagen type 1 (collagen Ⅰ) was tested by immunofluorescence. The expression of runt-related transcription factor 2 (Runx2) was tested by immunohistochemistry. The mRNA levels of collagen Ⅰ and Runx2 were detected by quantitative real-time PCR (qRT-PCR). The protein expressions of collagen Ⅰ, Runx2 and nuclear factor (NF)-κB were determined by Western blot. Primary rat aortic smooth muscle cells (VSMCs) were cultured in three conditions: normal glucose (NG), high glucose (HG) and glucose fluctuations (GF). Cells in GF group were incubated for 72 hours with glucose alternating between 5.5 and 25 mmol/L every 12 hours. TPCA-1, the inhibitor of NF-κB, the expression of collagenⅠin different groups of cells was tested by immunofluorescence. The protein expressions of collagen Ⅰ, Runx2 and NF-κB were also determined by Western blot. Results: (1) The quantitative ratios of the area of fibrosis in the C-STZ group, U-STZ group, STZ-GF group were (8.42±0.10)%, (21.30±0.74)% and (44.39±1.09)% (P<0.05), respectively. The means of integral optical density (IOD) of collagenⅠ in the three groups were 11.92±0.88, 50.04±3.56 and 77.52±2.69, respectively (P<0.05). The mRNA levels of collagenⅠ in the three groups were 1.00±0.10, 2.02±0.28 and 2.83±0.33, respectively (P<0.05). The protein expressions of collagenⅠ in the three groups were 1.05±0.03, 2.06±0.32 and 4.93±0.25, respectively (P<0.05). (2) The average IOD of Runx2 in the three groups were 150.00±7.35, 204.84±2.32 and 391.48±7.13, respectively (P<0.05). The mRNA levels of Runx2 in the three groups were 1.02±0.02, 1.27±0.04 and 2.18±0.12, respectively (P<0.05). The protein expressions of Runx2 in the three groups were 1.03±0.01, 2.34±0.36 and 4.52±0.75, respectively (P<0.05). (3) The protein expressions of NF-κB in the three groups were 1.02±0.01, 1.96±0.13 and 2.64±0.21, respectively (P<0.05). (4) In vitro, application of inhibitor of NF-κB reversed glucose fluctuations-induced upregulation of protein levels of Col Ⅰ and Runx2 (P<0.05). Conclusion: Glucose fluctuations could aggravate aortic fibrosis through activating Runx2 via NF-κB signaling pathways.
Assuntos
Animais , Masculino , Ratos , Aorta , Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 1 , Fibrose , Glucose , NF-kappa B , Ratos Sprague-DawleyRESUMO
Objective The recurrence rate of atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA) remains relatively high. The aim of this study was to investigate the predictive value of rs2200733 polymorphism for AF recurrence after RFCA. Methods Fifty-three AF patients underwent RFCA guided by the magnetic navigation system between July 2015 and September 2016 in Wuxi People’s Hospital. We obtained the baseline data on the patients, conducted genotyping for rs2200733 variants, and followed up the patients for symptoms and complications by electrocardiography (ECG) and dynamic ECG. Using Cox survival analysis, we determined the independent predictors of AF recurrence after RFCA and the sensibility and specificity of predicting AF recurrence at 12 and 24 months post-operatively. Results All the patients were Han Chinese, followed-up for 21.6 ± 9.5 months, and 25 (47.2%) of them experienced AF recurrence at 6.6 ± 5.3 months after RFCA. Kaplan-Meier survival analysis revealed a significant association between rs2200733 polymorphism and AF recurrence in the additive and recessive models (P < 0.001), and multivariate Cox analysis showed the rs2200733 polymorphism (recessive model) to be an independent predictor of post-RFCA AF recurrence (OR = 3.184, 95% CI: 1.378-7.357, P = 0.007). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of rs2200733 TT in predicting AF recurrence at 12 months were 64%, 81%, 70%, 76% and 74%, and those at 24 months were 60%, 82%, 75%, 70%, and 72%, respectively. Conclusion The rs2200733 polymorphism is an independent predictor of AF recurrence after RFCA, and its high specificity indicates that it could be used as a tool for screening Han Chinese patients with AF for RFCA.
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Objective The mechanisms of docosahexaenoic acid (DHA) protecting the cardiovascular system have not yet been clarified. This study was to investigate the vasorelaxative effect of 13,14-epoxy docosapentaenoic acid (13,14-EpDPE) on coronary arterioles in normal rats and its action mechanisms.Methods We isolated coronary artery smooth muscle cells (CASMCs) from normal rats by enzyme digestion, examined the open probabilities of the large conductance calcium-activated potassium (BK) channels in inside-out single channel configuration in the presence of different concentrations (0, 1, 10 and 100 pmol/L) of 13,14-EpDPE, and recorded the BK currents with the patch clamp in whole cell configuration. Then we assessed the coronary arterial relaxation by measuring dilatory responses to 13,14-EpDPE in pre-contracted tissues with or without pre-treatment with iberiotoxin.Results In the presence of 0, 1, 10 and 100 pmol/L of 13,14-EpDPE, the open probabilities of the BK channels were 0.25±0.03, 0.34±0.03, 0.44±0.06 and 0.85±0.16 (n=6), respectively, significantly increased at 100 pmol/L as compared with 0, 1 and 10 pmol/L (P<0.05). The BK channels were activated by 13,14-EpDP in a concentration-dependent manner and its half-effect concentration was (15.94±1.21) pmol/L. The current density was increased from (58.27±16.35) to (95.94±23.00) pA/pF (P=0.002) after 10 pmol/L 13,14-EpDP perfusion when the stimulation voltage was 100 mV. 13,14-EpDPE dilated the isolated coronary arterioles in a dose-dependent manner, and its effects were abolished after pre-treatment with iberiotoxin (100 nM).Conclusion 13,14-EpDPE can dilate coronary arterioles by activating BK channels in CASMCs, which might be one of the mechanisms underlying its protective effect on the cardiovascular system.