敲除腺苷A2A受体基因对慢性低O_(2)高CO_(2)模型小鼠前额叶皮质细胞凋亡及磷酸化p38MAPK蛋白的影响

Adenosine A2A receptor deficiency prevents p38MAPK activation and apoptosis of prefrontal cortex cells in mice with chronic hypoxic hypercapnia

目的观察敲除腺苷A_(2A)受体基因对慢性低O_(2)高CO_(2)模型小鼠前额叶皮质细胞凋亡以及磷酸化p38丝裂原活性蛋白激酶(p-p38MAPK)蛋白表达的影响。方法采用随机数字表法将16只腺苷A2A受体野生型(+/+)小鼠和16只腺苷A2A受体基因敲除型(-/-)小鼠各分为2个亚组,分别是对照-野生基因组、4周低O_(2)高CO_(2)-野生基因组(简称模型-野生基因组)、对照-基因敲除组、4周低O_(2)高CO_(2)-基因敲除组(简称模型-基因敲除组),每组各8只小鼠。将模型-野生基因组、模型-基因敲除组小鼠置于常压低O_(2)高CO_(2)动物舱内,舱内O_(2)浓度维持在9%-11%水平,CO_(2)浓度维持在5.5%-6.5%水平,每天干预8 h,每周干预6 d,持续干预4周。于4周制模结束后采用原位末端标记法(TUNEL)检测各组小鼠前额叶皮质细胞凋亡情况,采用蛋白免疫印迹法检测各组小鼠前额叶皮质磷酸化p38MAPK蛋白表达水平。结果两模型亚组前额叶皮质凋亡细胞数量均较相应的对照亚组明显增加(P<0.05),并且模型-野生基因组皮质凋亡情况较模型-基因敲除组更显著(P<0.05);两模型亚组前额叶皮质p-p38MAPK蛋白表达均较相应的对照亚组明显上调(P<0.05),并且模型-野生基因组p-p38MAPK蛋白表达上调幅度较模型-基因敲除组更显著(P<0.05)。结论敲除腺苷A2A受体基因能抑制慢性低O_(2)高CO_(2)模型小鼠前额叶皮质p38MAPK信号转导通路活化,减少前额叶皮质神经细胞凋亡,为改善慢性阻塞性肺疾病(COPD)患者认知功能提供更多实验依据。

Objective To observe the effect of genetic inactivation of adenosine A_(2A) receptor on apoptosis in the prefrontal cortex and on the expression of phosphorylated p38 mitogen-active protein kinase(p38MAPK)in mice with chronic hypoxic hypercapnia.Methods Sixteen male wild-type mice and 16 male mice in which the adenosine A2A receptor gene had been knocked out were randomly divided into a 4 weeks group(including 4HH+/+and 4HH-/-subgroups)and a normal control group(including NC+/+and NC-/-subgroups).The 4HH+/+and 4HH-/-group mice were exposed to an atmosphere containing 9-11%O_(2)and 5-6%CO_(2)8 hours a day,6 days a week for 4 weeks.The apoptosis index(AI)in their prefrontal cortices was then evaluated using terminal-deoxynucleoitide transferase mediated nick end labelling(TUNEL)staining.The expression of p38MAPK protein in the prefrontal cortices was measured using western blotting.Results The average AI had increased significantly in the 4HH+/+and 4HH-/-groups compared with the controls,with significantly more apoptotic cells in the 4HH+/+group than in the 4HH-/-group.In the 4HH+/+and 4HH-/-groups the average expression of p38 protein in the prefrontal cortex was significantly higher than among their controls.Moreover,the average expression of p-p38MAPK protein in the prefrontal cortex of the 4HH-/-group was significantly lower than in the 4HH+/+group.Conclusion Adenosine A2A receptor knockout inhibits apoptosis in the prefrontal cortex and down-regulates the p38MAPK activation of mice after exposure to chronic hypoxic hypercapnia.