间歇低氧大鼠神经元特异性烯醇化酶蛋白的表达及其对学习记忆功能的影响

Expression of neuron-specific enolase protein in rats after intermittent hypoxia and its influence on learining and memory function

目的 通过观察间歇低氧后大鼠脑内及血清神经元特异性烯醇化酶（NSE）蛋白表达及学习记忆功能的影响,探讨NSE蛋白表达与学习记忆功能改变的关系.方法 成年雄性Wistar大鼠48只,采用随机数字表法分为2组：空白对照组（UC组）、7.5％慢性间歇性低氧组（7.5％CIH组）.采用自制低氧舱模拟7.5％慢性间歇低氧模型.分别在第2,4,6,8周应用Morris水迷宫实验检测大鼠学习记忆功能;采用免疫组化法检测海马CA1区神经细胞NSE蛋白表达,同时采用酶联免疫吸附法检测大鼠血清NSE蛋白表达.结果 与空白对照组比较,7.5％ CIH组在2,4,6,8周大鼠逃避潜伏期时间分别为（44.13±2.84）s、（50.35±1.96）s、（57.47±1.66）s、（62.85±1.80）s,从第2周起随低氧时间延长大鼠逃避潜伏期时间延长（P＜0.05）;跨越目标象限时间分别为（48.81±2.09）s、（42.04± 1.84）s、（36.82±2.07）s、（31.81士1.68）s,从第2周起随低氧时间延长大鼠跨越目标象限时间缩短（P＜0.05）.7.5％CIH组海马CA1区神经细胞NSE蛋白表达在2,4,6,8周分别为（9.69±1.37）、（17.10±1.87）、（24.79±3.51）、（34.16±5.35）,血清NSE蛋白表达在2,4,6,8周分别为（6.03±0.91） μg/L、（11.04±1.89）μg/L、（16.39±1.00） μg/L、（24.22±3.73） μg/L,均多于空白对照组,差异有统计学意义（P均＜0.05）;7.5％CIH组海马CA1区神经细胞及血清NSE蛋白表达均有明显的时间差异性,均随时间的延长逐渐升高,差异有统计学意义（均P＜0.05）,海马CA1区NSE蛋白的阳性表达相对值与血清NSE蛋白的表达呈正相关（r=0.94、P＜0.01）;空白对照组NSE蛋白表达无时间差异性（均P＞0.05）.结论 间歇低氧可引起血清及脑组织NSE水平明显升高,两者动态变化均可以反映大鼠学习记忆功能下降的严重程度.

Objective To observe the changes of learning function and neuron-specific enolase （NSE）protein of both brian and serum in rats after intermittent hypoxia,and explore the relation between NSE protein and learning and memory function.Methods Male Wistar adult rats（n=48）were randomly divided into control group （UC group） and 7.5% chronic intermittent hypoxia group （7.5%CIH group）.7.5% chronic intermittent hypoxia model in rats were simalated by using the self-made cabin of intermittent hypoxia.At the 2nd,4th,6th,and 8th week respectively,learning and memory function in rat was tested by Morris water maze in two groups.The level of NSE protein in hippocampal CA1 region was detected by immunohistochemical method,and was detected in serum of rats by using enzyme-linked immunosorbent adsorption method.Results Compared with the control group,7.5% CIH group at the 2nd,4th,6th,and 8th week in rats from the second week of the escape latency time was 44.13± 2.84） s,（50.35 ± 1.96） s,（57.47 ± 1.66） s,（62.85 ± 1.80） s,and across the target quadrant time was 48.81 ± 2.09） s,（42.04± 1.84） s,（36.82± 2.07） s,（31.81 ± 1.68） s.From the first two weeks,the longer the hypoxia time prolonged,the longer the rat＇s escapedlatency （P〈0.05） and the shorter the rats acrossed the target quadrant （P 〈0.05）.7.5% CIH group of hippocampal CA1 neurons NSE protein at the 2nd,4th,6th,and 8th week was （9.69±1.37）,17.10± 1.87）,（24.79± 3.51）,（34.16±5.35）,respectively,and serum NSE protein at the 2nd,4th,6th,and 8th week respectively was （6.03±0.91） μg/L,（11.04± 1.89） μg/L,（16.39± 1.00） μg/L,（24.22±3.73） μg/L,both of which were more than the control group.The difference was statistically significant （P〈0.05）.7.5% CIH group of hippocampal CA1 neurons and serum NSE protein expression were significant time differences,and gradually increased over time.The difference was statistically significant （P〈0.05）.Positive NSE protein expression in hippocampal CA1 region relative NSE and serum protein expression values were positively correlated （r=0.94,P 〈0.01）.But in control group NSE protein expression did not exist time difference （P〉0.05）.Conclusion Intermittent hypoxia can cause NSE levels significant increase in serum and brain tissue,and the dynamic changes of them can reflect severity of learning and memory impairement in rat.