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背景已有研究发现年龄与性别可以对血压的昼夜节律产生一定影响,但这些因素对内皮素1与一氧化氮这两种重要的血管活性物质昼夜节律的影响尚缺乏充分研究。目的以不同年龄和性别的大鼠为实验对象,探讨收缩压、血液中内皮素1和一氧化氮的昼夜节律特征。方法选择SD大鼠128只,分为4大组,每组32只,分别为:①成年雄性鼠,即10周龄雄性大鼠。②成年雌性鼠,即10周龄雌性大鼠。③老年雄性鼠,即96周龄雄性大鼠。④老年雌性鼠,即96周龄雌性大鼠。适应性饲养8周后,采用鼠尾测压仪测定大鼠的收缩压后,并分别于不同时间点(2:00、8:00、14:00、20:00)处死大鼠,每个时间点处死每组中8只大鼠。并留取血,分别采用放免法和硝酸还原法检测血液中内皮素1、一氧化氮的含量。结果①与成年雄、雌性鼠相比,老年雄、雌性鼠各时间段收缩压均明显升高(P<0.01),其血液中内皮素1、一氧化氮均降低(P<0.05)。与成年雄性鼠相比,成年雌性鼠的收缩压及血浆内皮素1降低,血清一氧化氮增加(P<0.05);与老年雄性鼠相比,老年雌性鼠收缩压无明显变化(P>0.05),血液中内皮素1、一氧化氮均降低(P<0.05)。②4组大鼠收缩压、内皮素1及一氧化氮曲线的基本昼夜节律均存在。与成年鼠相比,老年鼠的收缩压峰值位相明显不同。成年雄性鼠与成年雌性鼠的收缩压峰值相位不同;而老年雄性鼠和老年雌性鼠收缩压峰值相位无明显变化。在4组大鼠血液中内皮素1和一氧化氮的峰值相位发生不同程度的移位,昼夜节律特征发生了明显变化。结论不同年龄和性别对于大鼠收缩压、血液中内皮素1和一氧化氮的时间生物学特征有影响。
Background Studies have found that age and gender may have an impact on circadian rhythm of blood pressure, but these factors have not sufficiently studied the circadian rhythm of endothelin-1 and nitric oxide, two important vasoactive substances. Objective To investigate the circadian rhythm of systolic blood pressure, endothelin-1 and nitric oxide in blood of different age and sex rats. Methods 128 SD rats were selected and divided into 4 groups, 32 in each group. They were: ① adult male rats, 10-week-old male rats. ② adult female rats, that is, 10-week-old female rats. ③ old male rats, that is, 96-week-old male rats. ④ old female rats, that is, 96-week-old female rats. After 8 weeks of adaptive feeding, the rat’s systolic pressure was measured by a rat tail manometer and the rats were sacrificed at different time points (2: 00,8: 00,14: 00,20: 00) At the time point, 8 rats in each group were sacrificed. And blood was collected for detection of endothelin-1 and nitric oxide in blood by radioimmunoassay and nitrate reduction respectively. Results Compared with adult male and female mice, the systolic blood pressure of male and female mice were significantly increased at each time point (P <0.01), and the levels of ET-1 and NO in blood decreased (P <0.05). Systolic blood pressure, plasma endothelin 1 and serum nitric oxide were increased (P <0.05) in adult female rats compared with those of adult male rats. Compared with male rats, systolic blood pressure did not change significantly in old female rats (P> 0.05 ), Blood endothelin 1, nitric oxide were decreased (P <0.05). ② The systolic blood pressure, the basic circadian rhythms of endothelin-1 and nitric oxide were all existed in the four groups. Compared with adult mice, the peak systolic pressure in aged rats significantly different phase. The peak systolic pressures of male and adult female rats were different from each other. However, there was no significant difference in systolic pressure peak between male and female aged rats. The peak phase of endothelin-1 and nitric oxide shifted to different degrees in the blood of four groups, and the circadian rhythm characteristics changed significantly. Conclusion Different age and gender have different effects on the systolic blood pressure, the temporal biology of endothelin-1 and nitric oxide in blood.