寒冷和高盐损害高血压大鼠肾小球与肾小管的差异

The difference of renal glomerulus and tubule dysfunction in hypertensive rats induced by cold and high-salt

目的观察寒冷、高盐和复合刺激对大鼠24h尿微量白蛋白(MAU)与视黄醇结合蛋白(RBP)排出量的影响,以探讨不同应激对肾小管和肾小球功能损害的差异。方法雄性SD大鼠32只,随机分为4组:对照组、寒冷组(每天于5℃人工气候箱4h)、高盐组(含8%食盐饲料喂养)、复合组(8%食盐饲料和冷刺激),每组8只。每周测收缩压2次,为期8周,计算收缩压曲线下面积(SBP-AUC)。于第3天、4周末、8周末收集24h尿液,计测24hMAU和尿RBP排出量。结果 8周期间复合组、寒冷组和高盐组的SBP-AUC均明显高于对照组[(938.6±52.9)、(871.2±52.5)和(866.4±56.2)比(777.6±26.7)mmHg.周,均P<0.01],但高盐组与寒冷组之间差异无统计学意义。寒冷组8周末24hMAU排出量明显高于高盐组[(5.4±0.9)比(4.4±0.8)mg,P<0.01];复合组、寒冷组和高盐组24h尿RBP排出量均明显高于对照组[(109.7±19.4)、(71.5±20.1)和(86.9±9.7)比(37.3±13.6)μg,均P<0.01]。寒冷组虽低于高盐组,但差异无统计学意义。虽然3个干预组24hMAU和尿RBP排出量之间均呈显著正相关,但寒冷组相关性较高盐组更强(r=0.78和r=0.56,P<0.01)。结论在收缩压负荷相似的情况下,寒冷应激导致更为明显的肾小球功能损害,而高盐更易损害肾小管功能。

Objective To investigate the difference of renal glomerulus and tubule dysfunction in rats with cold and salt stress by 24 urinary microalbumin（MAU）and retinol binding protein（RBP）excretion.Methods Thirty-two male SD rats were randomly divided into 4 groups（n=8）：Control group,Cold group [exposed to cold（5 ℃）for 4 h/d ],high-salt group（fed with 8 % NaCl diets）,Combined group（combination of 8 % NaCl diets and cold exposure）.Systolic blood pressure（SBP）was measured twice per week during the 8 week duration to obtain the area under the SBP curve（SBP-AUC）.In the third day,the 4th and the 8th week,24 h urinary MAU and RBP excretion were measured respectively.Results The SBP-AUCs in 3 intervention groups were significantly higher than that of control group [（938.6±52.9）,（871.2±52.5）and（866.4±56.2）vs（777.6±26.7）mm Hg.w,all P〈0.01 ],but no difference between high salt and cold groups.The 24 h MAU excretion was significantly higher in cold group than in high-salt group [（5.4±0.9）vs（4.4±0.8）mg,P〈0.01 ] at the 8th week.The 24 h RBP excretion in combined,cold and high-salt groups were significantly higher than in control group [（109.7±19.4）,（71.5±20.1）and（86.9±9.7）vs（37.3±13.6）μg,P〈0.01 ],but the value was slightly lower in cold group than in high-salt group.There was a significantly positive correlation between 24 h MAU and RBP excretion in 3 interval groups,but the correlation was stronger in cold group（r=0.78）then in high salt group（r=0.56）.Conclusion Under similar SBP loading,cold stress induces more serious glomerulus dysfunction,but high-salt intake does more serious tubule dysfunction in rats.