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目的观察肾上腺髓质素2(ADM2)对血管紧张素Ⅱ(AngⅡ)刺激血管平滑肌细胞(VSMCs)增殖的影响。方法采用培养的大鼠胸主动脉VSMCs,分为5组:对照组(n=6)、ADM2组(10-9～10-6mol/L,n=24)、AngⅡ组(10-7mol/L,n=6)、AngⅡ(10-7mol/L)+ADM2(10-9～10-6mol/L)组(n=24)、ADM2受体拮抗剂(ADM22-52或CGRP8-37)组(n=12)。用胸腺嘧啶核苷(3H-TdR)掺入法检测细胞DNA合成,噻唑兰比色法(MTT)观察VSMCs增殖,并加入受体拮抗剂后观察其促增殖作用。结果不同浓度的ADM2对未经AngⅡ诱导的VSMCs呈剂量依赖性地促增殖作用(P<0.01)。ADM2(10-9～10-6mol/L)抑制AngⅡ引起VSMCs的3H-TdR掺入量的增加,与AngⅡ组比较,AngⅡ+ADM2(10-9～10-6mol/L)组VSMCs的DNA合成抑制率分别为28%、32%、44%和52%(均P<0.01)。MTT结果显示,增殖抑制率分别为9%、14%、16%和20%(均P<0.01)。拮抗剂降钙素基因相关肽8-37(CGRP8-37)和ADM22-52消除了ADM2对AngⅡ增殖细胞作用的抑制。与不加拮抗剂相比,分别增高了34%和43%(P<0.01)。结论ADM2可抑制AngⅡ诱导的VSMCs增殖肥大的作用,从而完成其扩张血管、进而降低血压的作用。
Objective To investigate the effects of adrenomedullin 2 (ADM2) on the proliferation of vascular smooth muscle cells (VSMCs) stimulated by Angiotensin Ⅱ (AngⅡ). Methods Rat VSMCs were divided into 5 groups: control group (n = 6), ADM2 group (10-9 ~ 10-6mol / L, n = 24), Ang Ⅱ group (n = 24), ADM2 receptor antagonist (ADM22-52 or CGRP8-37) group (n = 6), AngⅡ (10-7mol / L) n = 12). The DNA synthesis was detected by 3H-TdR incorporation method. VSMCs proliferation was observed by MTT assay. The proliferation of VSMCs was observed by the addition of receptor antagonist. Results Different concentrations of ADM2 could promote proliferation in a dose - dependent manner without Ang Ⅱ (P <0.01). ADM2 (10-9 ~ 10-6mol / L) inhibited the increase of 3H-TdR incorporation in VSMCs induced by AngⅡ. Compared with AngⅡgroup, DNA synthesis of VSMCs in AngⅡ + ADM2 group The inhibition rates were 28%, 32%, 44% and 52%, respectively (all P <0.01). MTT results showed that the proliferation inhibition rates were 9%, 14%, 16% and 20% (all P <0.01). The antagonist calcitonin gene-related peptide 8-37 (CGRP8-37) and ADM22-52 abolished the inhibitory effect of ADM2 on Ang II proliferating cells. Increased 34% and 43% respectively compared with no antagonist (P <0.01). Conclusions ADM2 can inhibit the proliferation and hypertrophy induced by Ang Ⅱ in VSMCs, and thus complete its function of dilating blood vessels and further lowering blood pressure.