替米沙坦通过上调大鼠视网膜ACE2-Ang-（1—7）-Mas轴抑制细胞凋亡

Telmisartan reduces retina vessel endothelial cell apoptosis via upregulating retinal ACE2-Ang-（ 1- 7 ）-Mas axis in spontaneous hypertensive rats

目的研究血管紧张素Ⅱ受体拮抗剂替米沙坦对自发性高血压大鼠（spontaneouslyhypertensionrat，SHR）视网膜血管紧张素转化酶2（ACE2）一血管紧张素（1—7）[Ang-（1—7）]-G蛋白耦联受体Mas轴的影响，以及其对视网膜血管内皮细胞凋亡的作用。方法SHR36只，雄性，16周龄，随机数字表法分成3组，即SHR组、SHRT组和SHRTA组，每组12只。SHRT组给予替米沙坦lOmg·kg-1·d-1灌胃，SHRTA组给予替米沙坦10mg·kg-1·d-1灌胃，并给予选择性Ang-（1-7）拮抗剂A-7790．5mg·kg-1·d-1静注，SHR组不予药物处理，另设12只同周龄雄性京都种大鼠（WistarKyotorat，WKY大鼠）作为对照组。分别测定给药前（16周龄时）及给药后（24周龄时）大鼠鼠尾收缩压，于24周处死大鼠，采用实时定量聚合酶链反应（qRT—PCR）、蛋白印迹法（Westernblot）、免疫组织化学法分别检测视网膜ACE2、MasmRNA和蛋白表达水平，ELISA检测血清Ang-（1—7）浓度，苏木素伊红（HE）染色观察视网膜血管铺片毛细血管情况，原位DNA末端酶标记技术（TUNEL）检测视网膜血管铺片细胞凋亡情况。结果16周龄时SHR组、SHRT组和SHRTA组大鼠鼠尾收缩压均较对照组高（P均〈0．01），24周龄时SHRT组大鼠鼠尾收缩压较SHR组低（P〈0．01），SHRTA组则较SHRT组高（P〈0．05）。24周龄时SHR组大鼠视网膜ACE2mRNA和蛋白表达水平均低于对照组和SHRT组（P均〈0．01），而SHRT组与SHRTA组问差异无统计学意义（P〉0．05）。24周龄时SHR组大鼠视网膜MasmRNA和蛋白表达水平均低于对照组（P均〈0．01），SHRT组均高于SHR组（P均〈0．01），SHRTA组则均低于SHRT组（P均〈0．05）。24周龄时SHR组大鼠血清Ang．（1-7）浓度低于对照组（P〈0．01），SHRT组高于SHR组（P〈0．05），SHRTA组则低于SHRT组（P〈0．01）。24周龄时SHR组大鼠视网膜血管铺片TUNEL阳性细胞百分率高于对照组（P〈0．01），SHRT组低于SHR组（P〈0．01），SHRTA组则高于SHRT组（P〈0．05）。结论替米沙坦可上调SHR视网膜ACE2-Ang-（1-7）-Mas轴，从而发挥抗视网膜血管内皮细胞凋亡的作用。

Objective To investigate the effects of angiotensin Ⅱ （ Ang Ⅱ ） antagonist tehnisartan on retina vessel endothelial cell apoptosis and its impact on the ACE2-Ang-（ 1-7 ）-Mas axis in spontaneous hypertensive rats （SHR）. Methods Thirty-six SHR 16 week-old were randomly divided into 3 groups （n = 12 each） ： SHR, SHRT （telmisartan 10 mg · kg-l · d-l by gastric gavage） and SHRTA group （telmisartan 10 mg · kg-1 · d-1 by gastric gavage plus intravenous injection of A-779 0. 5 mg · kg-l ·d-1 ） , twelve WKY rats served as normotensive control group. Systolic blood pressure was measured at pre-treatment and 8 weeks later. After 8 weeks, rats were sacrificed, the expression of ACE2 and Mas in retina were analyzed by qRT-PCR, Western blot and Immunohistochemistry, the Ang-（1-7） concentration in serum was measured by ELISA. Specimens were obtained and stained by hematoxylin and eosin, and the morphology of retina vessel was observed. Apoptosis of vessel endothelial cells were determined by using terminal deoxynucleotidyl transferase mediated dUTP nick end labeling method. Results The systolic blood pressure of SHR, SHRT and SHRTA groups at baseline were significantly higher than age-matched WKY group （ all P 〈 0.01 ）. Eight weeks later, the systolic blood pressure group was significantly lower in SHRT group than in the SHR group （P〈 0.01 ）, this effect was partly reversed in SHRTA group. The retinal ACE2 mRNA and protein expression was significantly lower in SHR group than in WKY and SHRT groups （ P 〈 0.01 ）, which was similar between SHRT group and SHRTA group （ P 〉 0.05 ）. The retinal Mas mRNA and protein expression were significantly lower in SHR group compared to WKY and SHRT groups （ all P 〈 0. O1 ） , which was significantly lower in SHRTA group than in the SHRT group （ P 〈 0. 05 ）. ELISA results showed that serum Ang-（1-7） protein level was significantly lower in SHR group than in WKY group and SHRT group （both P 〈0.05 ）, which was lower in SHRTA group compared to SHRT group. Retinal vessel endothelial cell apoptosis was higher in SHR group than in WKY group, which could be reduced by cotreatment with telmisartan and this beneficial effect could be reversed by A-779. Conclusion Telmisartan can reduce retinal vessel endothelial cell apoptosis via upregulating the ACE2-Ang-（ 1-7 ）-Mas axis.