Department of Pharmacology, Cardiac and Cerebral Vascular Research Center, Zhongshan School of Medicine, Sun Yat-Sen University, 74 Zhongshan 2 Rd, Guangzhou 510080, PR China.
Cardiovasc Res. 2013 Oct 1;100(1):134-42. doi: 10.1093/cvr/cvt156. Epub 2013 Jun 19.
We have previously demonstrated that ClC-3 chloride channel activity and expression are significantly increased in remodelled cerebral vessels of hypertensive rats. This study aims to examine whether this channel directly regulates cerebrovascular remodelling during hypertension by using ClC-3(-/-) mice.
After DOCA-salt treatment, medial cross-sectional area, media thickness, and media-lumen ratio of the basilar artery of ClC-3(+/+) mice were significantly increased, accompanied by reduced lumen diameter, indicating apparent vascular remodelling. The vascular ultrastructure of ClC-3(+/+) hypertensive mice by electron microscopy revealed obvious disarray of SMCs and extracellular matrix accumulation. Immunofluorescence analysis showed that fibronectin was overexpressed in ClC-3(+/+) DOCA-salt mice. All of these vascular structure alterations were prevented in ClC-3(-/-) mice despite DOCA-salt treatment. However, propranolol, which reduced blood pressure as effectively as ClC-3 deficiency, failed to prevent basilar artery from remodelling. The vascular structure injury in ClC-3(+/+) hypertensive mice was accompanied by significantly increased expression of matrix metalloproteinase (MMP)-2, membrane-type (MT)1-MMP, and tissue inhibitor of metalloproteinase (TIMP)-2, which was inhibited by ClC-3 knockout. Additionally, the increase in transforming growth factor (TGF)-β1 level in serum, as well as phosphorylation of Smad3 at serine 423/425 in basilar artery, induced by DOCA-salt, was markedly prevented in ClC-3(-/-) mice.
Our findings suggest that ClC-3 deficiency attenuates cerebrovascular remodelling possibly via the suppression of MMPs/TIMP expression and TGF-β1/Smad3 signalling pathway in this hypertension.
我们之前已经证明，ClC-3 氯离子通道的活性和表达在高血压大鼠重塑的脑血管中显著增加。本研究旨在通过使用 ClC-3(-/-) 小鼠来检验该通道是否直接调节高血压期间的脑血管重塑。
在 DOCA-盐处理后，ClC-3(+/+) 小鼠基底动脉的中膜横截面积、中膜厚度和中膜-腔比显著增加，伴随管腔直径减小，表明明显的血管重塑。电镜下 ClC-3(+/+) 高血压小鼠的血管超微结构显示出明显的平滑肌细胞和细胞外基质堆积紊乱。免疫荧光分析显示，纤维连接蛋白在 ClC-3(+/+) DOCA-盐小鼠中过表达。尽管给予 DOCA-盐，但 ClC-3(-/-) 小鼠所有这些血管结构改变均得到预防。然而，与 ClC-3 缺乏一样有效降低血压的普萘洛尔未能防止基底动脉重塑。ClC-3(+/+) 高血压小鼠的血管结构损伤伴随着基质金属蛋白酶 (MMP)-2、膜型 (MT)1-MMP 和金属蛋白酶组织抑制剂 (TIMP)-2 的表达显著增加，ClC-3 敲除抑制了这种增加。此外，DOCA-盐诱导的血清中转化生长因子 (TGF)-β1 水平增加以及基底动脉中 Smad3 丝氨酸 423/425 的磷酸化在 ClC-3(-/-) 小鼠中明显受到抑制。
我们的研究结果表明，ClC-3 缺乏可能通过抑制 MMPs/TIMP 表达和 TGF-β1/Smad3 信号通路来减轻这种高血压中的脑血管重塑。
