常压缺氧性脑损伤小鼠血清蛋白质表达谱的变化及意义

目的观察常压缺氧小鼠脑组织损伤之特点及其血清差异蛋白质表达,探寻常压缺氧性脑损伤的生物标志蛋白。方法60只雌性昆明小鼠,随机分为正常对照组和常压缺氧组,建立常压缺氧小鼠模型并按缺氧持续时间分为缺氧1周、2周和3周组,分别检测血清和脑组织中超氧化物歧化酶活性和丙二醛含量;应用弱阳离子交换芯片结合表面增强激光解析电离飞行时间质谱技术分析常压缺氧后不同时间血清蛋白质表达谱的变化。结果常压缺氧后小鼠血清超氧化物歧化酶活性逐渐降低,其中缺氧3周组与正常对照组之间差异有统计学意义（P〈0.01）;常压缺氧2周组小鼠血清丙二醛含量明显升高,与正常对照组和缺氧1周组比较差异有统计学意义（均P〈0.01）。常压缺氧后各亚组小鼠脑组织中超氧化物歧化酶活性与正常对照组比较差异无统计学意义（均P〉0.05）;常压缺氧后脑组织中丙二醛含量呈升高趋势,缺氧2周组和3周组与正常对照组比较差异有统计学意义（均P〈0.01）。弱阳离子交换芯片结合质谱分析共获得342个血清蛋白质峰,其中相对分子质量为3500、3578、3706、3516和4130等5个蛋白质峰的相对强度在缺氧性脑损伤后升高,与正常对照组相比差异有统计学意义（P〈0.05）;另有73个蛋白质峰分布于各缺氧组但在正常对照组中未检测到。这78个蛋白质峰中30个蛋白质峰于缺氧后≤2周表达,48个蛋白质峰于缺氧2周后表达。结论常压缺氧可引起小鼠脑组织损伤,使血清及脑组织中与氧自由基相关的酶活性发生改变,血清超氧化物歧化酶活性降低,血清及脑组织中丙二醛含量升高;并可改变血清蛋白质的表达谱。提示血清中出现的部分蛋白质可能为常压缺氧性脑损伤诱导的血细胞基因表达产物,在血清中所检测到的差异蛋白质以及缺氧后新出现的蛋白质可能是脑损伤的生物标志蛋白。

Changes and significance of serum protein expression pattern in mice with cerebral normobaric anoxic injury

Objective To observe the cerebral changes and the serum differential protein expression pattern in mice with normobaric anoxic injury, and to find biomarker protein in normobaric anoxic injury. Methods Sixty female Kunming mice were randomly divided into normal control group and normobaric anoxic injury groups. The established normobaric anoxic mice models were divided into 1-week, 2-week, and 3-week groups according to the duration of anoxia. The activity of superoxide dismutase (SOD) and content of malondialdehyde (MDA) in serum and brain were examined. The changes of serum protein expression pattern were monitored with weak cationic exchanger (WCX-2) chips by surface-enhanced laser desorption ionization-time of flight-mass spectrometry. Results Serum SOD activity gradually decreased after normobaric anoxia, there were significant differences in 3-week group compared with normal control group (P < 0.01). In comparison with normal control group and anoxia 1-week group, serum MDA content increased significantly in 2-week group (P < 0.01, for all). Compared with normal control group, there were no significant differences in brain tissue SOD activity in each group after normobaric anoxia (P > 0.05, for all). Brain tissue MDA content in anoxia 2-week group and 3-week group were significantly higher than that in normal control group (P < 0.01, for all). The spectrometric analysis of WCX-2 chips showed that the relative intensity of 5 protein peaks with relative molecular weight 3 500, 3 578, 3 706, 3 516 and 4 130 from the 342 serum protein peaks in protein chips increased after anoxic injury. The differences between normobaric anoxia groups and normal control group were significant (P < 0.05). Seventy-three serum protein peaks in normobaric anoxia groups were not detected in normal control group. Thirty protein peaks presented within 2 weeks and forty-eight presented after 2 weeks of anoxia in seventy-eight protein peaks. Conclusion Normobaric anoxia may cause cerebral injury in mice and induce changes of oxygen free radical-related enzyme activity in serum and brain tissue. Normobaric anoxia can decrease serum SOD activity and increase serum and cerebral MDA content, and may alter serum protein expression pattern. The results suggest that part of the serum protein may be the products of blood cells gene expression induced by normobaric anoxia injury. Different proteins detected in serum and new occurrence of protein after anoxia may be the biomarkers of cerebral injury.