激活TRPV1对自发性高血压大鼠血管平滑肌细胞增殖的影响

Effect of TRPV1 activation on proliferation of vascular smooth muscle cells in spontaneously hypertensive rats

目的探讨瞬时受体电位香草醛亚家族1(transient receptor potential vanilloid 1,TRPV1)对培养的血管平滑肌细胞(vascular smooth muscle cells,VSMCs)增殖的影响。方法用组织贴块法分别培养SHR和WKY大鼠的主动脉VSMCs,采用细胞免疫荧光进行鉴定。分别用辣椒素和iRTX激活和拮抗TRPV1受体,CCK-8法检测VSMCs增殖;Western blot法检测TRPV1、磷酸化-Akt(p-Akt)和总Akt(t-Akt)的蛋白表达。结果 1 SHR-VSMCs中TRPV1蛋白相对表达量低于WKY-VSMCs(0.32±0.05 vs 0.55±0.11,P<0.05);TRPV1激动剂辣椒素可显著上调SHR-VSMCs(0.65±0.19)和WKYVSMCs(0.89±0.13)中TRPV1的表达(P<0.05)。2 SHR-VSMCs的增殖能力高于WKY-VSMCs(1.30±0.07 vs 0.88±0.23,P<0.05);辣椒素呈剂量依赖性地抑制SHR-VSMCs的增殖(对照组:1.30±0.07,1μmol/L辣椒素组:0.93±0.10,10μmol/L辣椒素组:0.83±0.16,P<0.05);应用iRTX拮抗TRPV1即拮抗辣椒素的抗增殖作用(1μmol/L辣椒素组:0.93±0.10,1μmol/L辣椒素+1μmol/L iRTX组:1.23±0.14,P<0.05)。3SHR-VSMCs中Akt磷酸化水平高于WKY-VSMCs(0.44±0.02 vs0.29±0.09,P<0.05);辣椒素激活TRPV1抑制VSMCs中Akt的磷酸化(WKY-VSMCs:0.13±0.02,SHR-VSMCs:0.23±0.03,P<0.05);TRPV1拮抗剂iRTX可拮抗辣椒素作用,使WKY-VSMCs(0.37±0.07)、SHR-VSMCs(0.43±0.10)中Akt磷酸化水平升高(P<0.05)。结论激活TRPV1可能通过抑制Akt的磷酸化而抑制SHR-VSMCs增殖。

Objective To determine the effect of transient receptor potential vanilloid 1（ TRPV1） on the proliferation of vascular smooth muscle cells（ VSMCs） in spontaneously hypertensive rats（ SHR）.Methods VSMCs from aortas of SHR and corresponding age-matched Wistar Kyoto rats（ WKY） were cultured using a tissue explant method,and identified by morphology and immunofluorescence assay. TRPV1 was activated by its agonist capsaicin and inhibited by its antagnosit 5＇-iodo-resiniferatoxin（ iRTX）. Then,the proliferation of VSMCs was measured by CCK-8 assay. Western blotting was used to detect the expression of TRPV1,phosphorylated Akt（ p-Akt） and total Akt. Results The expression of TRPV1 was lower in SHR-VSMCs（ 0. 32 ± 0. 05） than in WKY-VSMCs（ 0. 55 ± 0. 11,P〈0. 05）. TRPV1 agonist capsaicin increased the TRPV1 protein expression in WKY-VSMCs（ 0. 65 ± 0. 198） and SHR-VSMCs（ 0. 89 ± 0. 13,P〈0. 05）. SHR-VSMCs showed higher proliferative capability than WKY-VSMCs（ 1. 30 ± 0. 07 vs 0. 88 ±0. 23,P〈0. 05）. TRPV1 agonist capsaicin inhibited the proliferation of SHR-VSMCs in a dose-dependent manner（ control group： 1. 30 ± 0. 07; 1 μmol / L capsaicin group： 0. 93 ± 0. 10; 10 μmol / L capsaicin group：0. 83 ± 0. 16,P〈0. 05）,which was counteracted by TRPV1 antagonist iRTX（ 1 μmol / L capsaicin group：0. 93 ± 0. 10; 1 μmol / L capsaicin ＋ 1 μmol / L iRTX group： 1. 23 ± 0. 14,P〈0. 05）. SHR-VSMCs showed increased expression of p-Akt in compared to WKY-VSMCs（ 0. 44 ± 0. 02 vs 0. 29 ± 0. 09,P〈0. 05）.Capsaicin reduced p-Akt expression in WKY-VSMCs（ 0. 13 ± 0. 02） and SHR-VSMCs（ 0. 23 ± 0. 03）（ P〈0. 05）,which was counteracted by TRPV1 antagonist iRTX（ WKY： 0. 37 ± 0. 07; SHR： 0. 43 ± 0. 10）（ P〈0. 05）. Conclusion Activation of TRPV1 suppresses the proliferation of VSMCs in SHR through downregulating the expression of p-Akt.