Wang Li-Jie, Liu Wei-Dong, Zhang Liang, Ma Ke-Tao, Zhao Lei, Shi Wen-Yan, Zhang Wen-Wen, Wang Ying-Zi, Li Li, Si Jun-Qiang
Department of Physiology, Medical College of Shihezi University, Shihezi, Xinjiang 832002, P.R. China.
Department of Gastroenterology, The People's Hospital of Xinjiang Uyghur Autonomous Region, Urumqi, Xinjiang 830001, P.R. China.
Mol Med Rep. 2016 Nov;14(5):4083-4090. doi: 10.3892/mmr.2016.5783. Epub 2016 Sep 26.
Niflumic acid (NFA) is a novel gap junction (GJ) inhibitor. The aim of the present study was to investigate the effect of NFA on GJ communication and the expression of connexin (Cx) in vascular smooth muscle cells (VSMCs) of mesenteric arterioles of spontaneously hypertensive rats (SHR). Whole‑cell patch clamp recording demonstrated that NFA at 1x10‑4 M significantly inhibited the inward current and its effect was reversible. The time for charging and discharging of cell membrane capacitance (Cinput) reduced from 9.73 to 0.48 ms (P<0.05; n=6). Pressure myograph measurement showed that NFA at 3x10‑4 M fully neutralized the contraction caused by phenylephrine. The relaxation responses of normotensive control Wistar Kyoto (WKY) rats were significantly higher, compared with those of the SHRs (P<0.05; n=6). Western blot and reverse transcription‑quantitative polymerase chain reaction analyses showed that the mRNA and protein expression levels of Cx43 of the third‑level branch of mesenteric arterioles of the SHRs and WKY rats were higher, compared with those of the first‑level branch. The mRNA and protein expression levels of Cx43 of the primary and third‑level branches of the mesenteric arterioles in the SHRs were higher, compared with those in the WKY rats (P<0.05; n=6). The mRNA levels of Cx43 in the mesenteric arterioles were significantly downregulated by NFA in a concentration‑dependent manner (P<0.01; n=6). The protein levels of Cx43 in primary cultured VSMCs isolated from the mesenteric arterioles were also significantly downregulated by NFA in a concentration‑dependent manner (P<0.01; n=6). These results showed that the vasorelaxatory effects of GJ inhibitors were reduced in the SHRs, which was associated with a higher protein expression level of Cx43 in the mesenteric arterioles of the SHRs. NFA also relaxed the mesenteric arterioles by reducing the expression of Cx43, which decreased blood pressure. Therefore, regulation of the expression of GJs may be a therapeutic target for the treatment of hypertension.
尼氟灭酸（NFA）是一种新型的缝隙连接（GJ）抑制剂。本研究旨在探讨NFA对自发性高血压大鼠（SHR）肠系膜小动脉血管平滑肌细胞（VSMC）中GJ通讯及连接蛋白（Cx）表达的影响。全细胞膜片钳记录显示，1×10⁻⁴ M的NFA显著抑制内向电流，且其作用是可逆的。细胞膜电容充电和放电时间（Cinput）从9.73 ms降至0.48 ms（P<0.05；n = 6）。压力肌动描记法测量显示，3×10⁻⁴ M的NFA完全中和了去氧肾上腺素引起的收缩。与SHR相比，正常血压对照Wistar Kyoto（WKY）大鼠的舒张反应显著更高（P<0.05；n = 6）。蛋白质印迹法和逆转录定量聚合酶链反应分析显示，与一级分支相比，SHR和WKY大鼠肠系膜小动脉三级分支中Cx43的mRNA和蛋白质表达水平更高。与WKY大鼠相比，SHR肠系膜小动脉一级和三级分支中Cx43的mRNA和蛋白质表达水平更高（P<0.05；n = 6）。NFA以浓度依赖性方式显著下调肠系膜小动脉中Cx43的mRNA水平（P<0.01；n = 6）。从肠系膜小动脉分离的原代培养VSMC中Cx43的蛋白质水平也被NFA以浓度依赖性方式显著下调（P<0.01；n = 6）。这些结果表明，GJ抑制剂的血管舒张作用在SHR中降低，这与SHR肠系膜小动脉中Cx43的蛋白质表达水平较高有关。NFA还通过降低Cx43的表达使肠系膜小动脉舒张，从而降低血压。因此，调节GJ的表达可能是治疗高血压的一个治疗靶点。
