高盐饮食对大鼠大脑皮质氧化应激及钠钙泵活性的影响

Effects of high salt diet on oxidative stress and Na^+-K^+-ATPase and Ca^(2+)-ATPase activities in cerebral cortex of Wistar rats

目的探讨长期高盐饮食对大鼠大脑皮质氧化应激和Na+-K+-ATPase、Ca2+-ATPase活性及其相关基因表达的影响。方法雄性Wistar大鼠随机分为正常盐对照组(NS组,n=13)、8%高盐组(HS组,n=24)和8%高盐+替米沙坦干预组(HS+Tel组,n=12),每2 w测量尾动脉压1次,喂养共24 w。比色法测定大鼠大脑皮质丙二醛(MDA)含量和超氧化物歧化酶(SOD)酶活性;用生化酶学法检测大脑皮质Na+-K+-ATPase、Ca2+-ATPase活性;通过实时荧光定量PCR法检测大脑皮质NAPDH、Na+-K+-ATPaseα1、细胞质膜钙泵(PMCA)1、钠钙交换蛋白(NCX)1和NADPH氧化酶亚单位P22phox mRNA表达。结果与NS组比较,HS组MDA含量增加、SOD活性减弱(P<0.05),Na+-K+-ATPase、Ca2+-ATPase活性均降低(P<0.05),NADPH氧化酶亚单位P22phox、Na+-K+-ATPaseα1、PMCA1 mRNA表达增加(P<0.05),NCX1mRNA表达无明显变化;与HS组比较,HS+Tel组Na+-K+-ATPase、Ca2+-ATPase活性升高(P<0.05),其他指标无明显改变。结论高盐饮食可引起大鼠大脑皮质氧化损伤及钠钙泵活性降低。

Objective To study the effects of high salt diet on oxidative stress and Na+-K+-ATPase and Ca2 +-ATPase activities and the mRNA expression in cerebral cortex of Wistar rats. Methods Wistar rats were divided into normal salt control( NS)( n = 13),high salt( 8%) model( HS,n = 24) and high salt + telmisartan( HS + Tel) groups( n = 12). Tail-cuff artery pressure was determined every 2 weeks.Values of SOD activity and MDA content were determined by colorimetry. The activities and mRNA levels of Na+-K+-ATPase and Ca2 +-ATPase in cerebral cortex were determined by enzyme colorimetry and real-time polymerase chain reaction( PCR),respectively. Results Compared with those of NS group,activity of SOD was decreased and MDA content was increased. The activities of Na+-K+-ATPase and Ca2 +-ATPase were significantly reduced,whereas the mRNA expressions of NAPDH,Na+-K+-ATPase α1 subunit and PMCA1 were increased.After treated with telmisartan,the activities of Na+-K+-ATPase and Ca2 +-ATPase became much higher compared with those of HS group.Conclusions Long-term high-salt diet could lead to oxidative stress and down-regulat activities of Na+-K+-ATPase and Ca2 +-ATPase in cerebral cortex.