长期雌激素替代治疗对血压及心肌IR和IRS-1表达的影响

目的：研究长期雌激素替代治疗对血压及心肌组织胰岛素受体（IR）和胰岛素受体底物-1（IRS-1）表达水平的影响。方法：将50只雌性SD大鼠随机分成3组，构建假手术、去势（去卵巢）和雌激素替代3组动物模型。手术前后,用尾套法测定大鼠的尾动脉收缩压，RT-PCR方法检测大鼠心肌IR和IRS-1的表达。结果：去势组血压［（118.75±2.77） mmHg］明显高于假手术组 ［（103.86±1.84）mmHg，P＜0.05］和替代组［（107.83±3.24）mmHg，P＜0.05］ 。去势组大鼠心肌IRS-1的相对表达量（1.2588±0.1045）显著低于假手术组（2.2089±0.0988, P＜0.05）和替代组(1.9100±0.1230，P＜0.05）。然而，替代组与假手术组间血压和IRS-1的表达无明显差异（P＞0.05）。假手术、去卵巢和替代组间心肌IR的表达差异无统计学意义（P＞0.05）。结论：长期雌激素替代治疗可降低血压、增加心肌细胞IRS-1的表达，从而一定程度上保护心血管。但血清雌激素水平对心肌细胞IR的表达影响不明显。

Effects of long-term estrogen replacement treatment on the blood pressure and expression of IR and IRS-1 in myocardium

OBJECTIVE: To determine the effects of long-term estrogen replacement treatment on blood pressure and expressions of insulin receptor (IR) and insulin receptor substrate-1 ( IRS-1) in myocardium. METHODS: Fifty female SD rats were randomly divided into 3 groups. And then sham ( n = 16), ovariectomy (OVX, n = 17), and estrogen replacement treatment group (OVX + E2, n = 17) were established. Systolic blood pressure of tail artery was determined by tail-cuff technique before the operation and on week 12 after the operation. The expressions of IR and IRS-1 were measured by RT-PCR in myocardium of SD rats. RESULTS: Blood pressure (118.75+/-2.77) mmHg] in OVX was significantly higher than that in the sham ( 103.86+/-1.84) mmHg, P < 0.05 ] and OVX + E2 ( 107.83+/-3.24) mmHg, P < 0.05 ] rats. Expression of IRS-1 in OVX group was significantly lower ( 1.2588+/-0.1045)than that in the sham(2.2089+/-0.0988, P <0.05) and OVX + E2 groups ( 1.9100+/-0.1230, P <0.05 ). However, there was no difference on blood pressure and expression of IRS-1 between sham and OVX + E2 groups (P > 0.05 ). The difference of IR expression has no statistical significance among the 3 groups. CONCLUSION: Long-term estrogen replacement treatment might protect cardiovascular system through decreasing the blood pressure and inducing the expression of IRS-1 in myocardium. However, plasma estrogen level doesn't significantly influence the IR expression.