长期雌激素替代治疗对血压及心肌IR和IRS-1表达的影响

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

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。

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 + E 2, 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+E 2 [(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+E 2 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+E 2 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.