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目的观察孕期给予高盐饮食后,胎鼠心肌细胞周期是否有改变及其与血管紧张素Ⅱ(AngⅡ)的关系。方法将SD大鼠随机分为正常组和高盐组,在孕3至21 d分别给予正常盐饮食和高盐饮食,孕21 d时检测母鼠和胎鼠的血钠浓度、血浆渗透压、血浆AngⅡ浓度以及胎鼠心脏组织中的AngⅡ含量,称量孕21 d胎鼠的心脏质量后,分离出心肌细胞,培养后检测细胞周期。结果与正常组相比,高盐组母鼠和胎鼠的血钠、血浆渗透压无明显改变(均P>0.05),母鼠和胎鼠血浆AngⅡ浓度明显降低,而胎鼠心脏局部AngⅡ明显增加(均P<0.05)。胎鼠心肌细胞G1期比例明显降低而S期比例明显增加,AngⅡ明显降低心肌细胞G1期比例并明显增加S期比例(均P<0.05),AngⅡ受体1型(AT1R)阻断剂可以阻断AngⅡ引起的细胞周期改变,而AngⅡ受体2型(AT2R)阻断剂对由AngⅡ引起的细胞周期改变无影响。结论孕期高盐饮食可能激活了胎鼠心脏局部AngⅡ,进而改变心肌细胞周期和影响胎鼠心脏发育,且AT1R介导了AngⅡ对心肌细胞周期的影响。
Objective To observe whether there is any change of cardiomyocyte cell cycle and its relationship with angiotensin Ⅱ (Ang Ⅱ) after high salt diet in pregnancy. Methods SD rats were randomly divided into normal group and high salt group. Normal saline diet and high salt diet were given on the 3rd to 21st day of pregnancy. The serum sodium concentration, plasma osmotic pressure, Plasma AngⅡ concentration and AngⅡ content in fetal rat heart tissue were measured. The heart mass of pregnant mice was weighed 21 days later and the cardiomyocytes were isolated. Cell cycle was detected after culture. Results Compared with the normal group, the serum sodium and plasma osmolality did not change in the high salt group (all P> 0.05), while that in the maternal and fetal rat was significantly lower than that in the normal group Increase (all P <0.05). The proportion of G1 phase in fetal rat cardiomyocytes was significantly decreased while the proportion of S phase was significantly increased. Ang Ⅱ significantly decreased the percentage of G1 phase and increased the proportion of S phase in cardiomyocytes (all P <0.05), while Ang II receptor type 1 (AT1R) AngⅡinduced cell cycle changes, whereas AngⅡreceptor type 2 (AT2R) blockers had no effect on cell cycle changes induced by AngⅡ. Conclusion High-salt diet during pregnancy may activate local AngⅡ in fetal rat hearts, thereby changing the cardiomyocyte cycle and affecting the fetal heart development. Moreover, AT1R mediates the effect of AngⅡ on cardiomyocyte cycle.