雌激素改善高血压靶器官损害与T淋巴细胞连接蛋白40表达的相关性

Correlation between improvement of target-organ damage of hypertension after estrogen intervention and experssion of connexin 40 in peripheral blood T lymphocyte subsets

目的观察雌激素改善高血压造成的靶器官损害与T淋巴细胞连接蛋白40(Cx40)表达的相关性。方法选取16～17周龄雄性自发性高血压大鼠(SHR)和WKY大鼠,SHR随机分为SHR组和雌激素干预SHR组。测量尾动脉压后,采用苏木素-伊红染色观察大鼠脑基底动脉和肾脏组织的病理学改变,应用流式细胞术检测大鼠外周血中CD4^+/CD8^+、CD4^+CD25^+T淋巴细胞比值以及Cx40在CD4^+和CD8^+T细胞的表达比例,应用酶联免疫吸附试验(ELISA)法检测血清炎症因子的表达。结果与WKY组相比,SHR组肾脏血管壁增厚,部分血管周围炎性细胞浸润和肾小球萎缩等肾损伤现象明显,雌激素干预组管壁增厚和炎性浸润程度均减弱;与WKY组相比,SHR组大鼠外周血CD4^+/CD8^+值升高(P<0.05),CD4^+CD25^+T细胞占CD4^+细胞比例降低(P<0.01),雌激素干预组较SHR组CD4^+/CD8^+值降低(P<0.05),CD4^+CD25^+T细胞占CD4^+细胞比例增高(P<0.05);与WKY组相比,SHR组外周血CD4^+、CD8^+T淋巴细胞上Cx40表达增高(P<0.01,P<0.05),雌激素干预组较SHR组外周血CD4^+、CD8^+T淋巴细胞上Cx40表达降低(P<0.05);与WKY组比较,SHR组大鼠血清中白细胞介素(IL)6和肿瘤坏死因子(TNF)α表达升高(P<0.05,P<0.01),雌激素干预组较SHR组大鼠血清中IL-6和TNF-α表达降低(P<0.05),而SHR组大鼠血清中IL-10表达低于WKY大鼠(P<0.01),雌激素干预组较SHR组IL-10表达升高(P<0.05)。结论雌激素改善高血压炎症造成的肾脏和脑血管损害可能与其抑制T淋巴细胞上Cx40的表达相关,其可能的机制是雌激素通过下调外周血T淋巴细胞Cx40的表达,抑制细胞间的缝隙连接通讯,进而抑制炎症因子的释放,从而改善高血压造成的靶器官损害。

Objective To investigate the correlation between the improvement of target organ damage and downregulation of the ratio of connexin 40 in peripheral blood T lymphocyte subsets induced by estrogen intervention in spontaneously hypertensive rats（SHR）. Methods Sixteen to seventeen-week-old male SHR and WKY rats were recruited and randomly divided into three groups：WKY,SHR and estrogen group（n=6,respectively）. After tail artery blood pressure measurement,the basilar artery and renal pathological changes were observed by HE staining;the ratio of CD4^＋/CD8^＋and CD4^＋CD25^＋T cells and the ratio of Cx40 on CD4^＋ and CD8^＋T cells were detected by flow cytometry;the expression of tumor necrosis factor（TNF）-α,interleukin（IL）-6 and IL-10 was detected by enzyme-linked immunosorbent assay（ELISA）. Results HE staining showed that,compared with WKY rats,there were evidently thicken on vascular wall,partly infiltration of inflammatory cell in the blood vessels and glomerular atrophy in SHR,but those phenomena were reversed partly in estrogen group.Compared with WKY rats,the ratio of CD4^＋/CD8^＋was higher（P〈0.05）and the proportion of CD4^＋CD25^＋T cells to CD4~＋cells was lower（P〈0.01）in SHR. However,the ratio of CD4^＋/CD8^＋was descended（P〈0.05）and the proportion of CD4^＋CD25^＋T cells to CD4^＋cells was increased in estrogen group compared with SHR group（P〈0.05）. Compared with WKY rats,the expression of Cx40 on CD4^＋and CD8^＋T cells were higher in SHR（P〈0.01,P〈0.05）. Whereas the expression of Cx40 on CD4^＋and CD8^＋T cells were descended in estrogen group compared with SHR group（P〈0.05）. Moreover,the serum level of IL-6 and TNF-αin SHR were higher than those in WKY rats（P〈0.05,P〈0.01）. And IL-10 was lower in SHR than that in WKY rats（P〈0.01）. After estrogen intervention,the serum level of IL-6 and TNF-αwas decreased（P〈0.05）and IL-10 was increased（P〈0.05）. Conclusion Estrogen could improve the renal and cerebrovascular damage in hypertension,which may be related to the expression of Cx40 in T lymphocytes. The possible mechanism could be that estrogen inhibit the gap junction intercelluar communication and reduce the ralease of inflammatory factors by downregulating the Cx40 in peripheral blood T lymphocyte subsets,and enventually improve the hypertensive target organ damage.