背景:高果糖消耗通过大鼠小胶质细胞相关的神经炎症增加血压。由于中等电导钙激活钾通道(KCa3.1)增强了小胶质细胞的反应性,我们研究了KCa3.1通道阻滞剂TRAM-34或米诺环素的预处理是否可以预防果糖喂养大鼠的高血压发展.
方法:该研究涉及雄性Wistar大鼠,给予高果糖(10%的饮用水)或自来水21天。果糖组也全身接受米诺环素或TRAM-3421天。我们测量了收缩压和舒张压(SBP和DBP),心率(HR)定期与尾袖;促炎细胞因子和胰岛素水平在血浆中通过ELISA,在21天结束时通过qPCR在孤束核(NTS)中和神经炎症标记物。我们还研究了离体大鼠肠系膜动脉中的内皮依赖性超极化(EDH)型血管舒张。
结果:SBP,DBP,果糖组HR升高。米诺环素和TRAM-34均显着阻止了这些增加。果糖摄入也增加了血浆IL-6,IL-1β,TNF-α,和胰岛素水平,而用TRAM-34预处理也防止了这些增加。在果糖喂养的高血压大鼠的NTS样品中,Iba-1而不是CD86水平显着升高,这暗示了小胶质细胞的增殖。在果糖组中,内皮KCa3.1介导的EDH型血管舒张作用减弱;然而,TRAM-34没有引起松弛的进一步恶化。
结论:TRAM-34在预防果糖诱导的高血压方面与米诺环素一样有效,而不干扰EDH型血管舒张。此外,TRAM-34缓解高果糖相关的全身性炎症。
BACKGROUND: High fructose consumption increases blood pressure through microglia-related neuroinflammation in rats. Since intermediate-conductance calcium-activated potassium channels (KCa3.1) potentiates microglial reactivity, we examined whether the pretreatment with the KCa3.1 channel blocker TRAM-34 or
minocycline prevents hypertension development in fructose-fed rats.
METHODS: The study involved male Wistar rats that were given either a high fructose (10% in drinking water) or a tap water for 21 days. Fructose groups also received
minocycline or TRAM-34 systemically for 21 days. We measured systolic and diastolic blood pressure (SBP and DBP), heart rate (HR) periodically with tail-cuff; proinflammatory cytokines and insulin levels in plasma via ELISA, and neuroinflammatory markers in the nucleus tractus solitarii (NTS) by qPCR at the end of 21 days. We also examined endothelium-dependent hyperpolarization (EDH)-type vasorelaxations in isolated mesenteric arteries of the rats ex vivo.
RESULTS: SBP, DBP, and HR increased in the fructose group. Both
minocycline and TRAM-34 significantly prevented these increases. Fructose intake also increased plasma IL-6, IL-1β, TNF-α, and insulin levels, whereas pretreatment with TRAM-34 prevented these increases as well. Iba-1, but not CD86 levels were significantly higher in the NTS samples of fructose-fed hypertensive rats which implied microglial proliferation. EDH-type vasorelaxations mediated by endothelial KCa3.1 attenuated in the fructose group; however, TRAM-34 did not cause further deterioration in the relaxations.
CONCLUSIONS: TRAM-34 is as effective as
minocycline in preventing fructose-induced hypertension without interfering with the EDH-type vasodilation. Furthermore, TRAM-34 relieves high fructose-associated systemic inflammation.