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目的 :观察 17β 雌二醇替代治疗对卵巢切除大鼠心肌组织中一氧化氮 (NO)和内皮源性一氧化氮合酶 (eNOS)的影响。方法 :成年雌性SD大鼠经双侧卵巢切除术 ,假手术组作为对照 ,术后 3周随机分为假手术组 ,模型对照组 ,17β 雌二醇(0 .1mg·kg-1·d-1)和溶媒 (芝麻油 )皮下注射治疗组 ,处理 6周 ,记录大鼠的血压、心率、子宫重量 ;检测血中雌二醇的含量 ;亚硝酸还原酶法检测心肌匀浆中NO含量 ;Westernblot分析心肌中eNOS及eNOS调节蛋白小凹蛋白 1(caveolin 1)的蛋白表达情况。结果 :17β 雌二醇治疗组的心率 (314± 16次 分 )较其他各组低 ,与溶媒对照组比较 ,雌二醇替代治疗组心肌匀浆中NO的含量增加一倍 ,eNOS蛋白表达明显增加 (P <0 .0 1) ,而作为eNOS的内源性抑制物caveolin 1的表达却明显减少 (P <0 .0 5 )。结论 :雌激素替代治疗直接增加卵巢切除大鼠心肌eNOS的表达量以及NO的产生 ,减少抑制eNOS活性的小凹蛋白 1表达。
Objective: To observe the effects of 17β-estradiol replacement therapy on nitric oxide (NO) and endothelium-derived nitric oxide synthase (eNOS) in myocardium of ovariectomized rats. METHODS: Adult female Sprague-Dawley rats were ovariectomized and sham-operated group served as control. The rats were randomly divided into sham operation group, model control group, 17β estradiol (0. 1 mg · kg -1 · d- 1) and vehicle (sesame oil) were injected subcutaneously in the treatment group for 6 weeks. The blood pressure, heart rate and uterus weight of the rats were measured. The content of estradiol in the blood was measured. NO content in the myocardial homogenate was detected by nitrite reductase method. The expression of eNOS and eNOS caveolin 1 in myocardium were analyzed. Results: The heart rate (314 ± 16) in the 17β estradiol treatment group was lower than that in other groups. Compared with the vehicle control group, the NO content in the myocardial homogenate of the estradiol replacement group doubled and the expression of eNOS protein was significant (P <0.01), while the expression of caveolin 1, an endogenous inhibitor of eNOS, was significantly reduced (P <0.05). Conclusion: Estrogen replacement therapy directly increases the expression of eNOS and NO in myocardium of ovariectomized rats and decreases the expression of caveolin-1, which inhibits eNOS activity.