烟碱型乙酰胆碱受体α7在Fmr1基因敲除小鼠中的表达及意义

Expression and significance of nicotinic acetylcholine receptor α7 in fmr1 knockout mice

目的观察烟碱型乙酰胆碱受体α7在Fmr1基因敲除小鼠前额皮层及海马的表达,探讨其在Fmr1基因敲除小鼠学习记忆中的作用。方法将4周龄FVB小鼠分为WT组和KO组,用跳台实验分别检测KO及WT小鼠学习记忆的能力,利用Western blotting和免疫组化方法检测KO及WT小鼠前额皮层及海马α7 nAChR的表达。结果跳台实验结果显示,与WT空白组比较,KO空白组第一天及第二天的潜伏期均显著缩短,错误次数明显增多,差异均具有统计学意义(P<0.05);免疫组化结果显示,与WT空白组相比,KO空白组前额皮层和海马区α7 nAChR免疫阳性细胞数均显著减少(P<0.05);Western Blotting结果显示,KO空白组前额皮层及海马区α7 nAChR表达量均较WT空白组减少,海马区更为显著,差异均具有统计学意义(P<0.05)。结论 Fmr1基因敲除小鼠前额皮层、海马区的α7 nAChR表达量较野生型小鼠减少,提示α7 nAChR参与了Fmr1基因敲除小鼠学习记忆障碍的发病机制。

Objective To study the expression and significance of α7 nicotinic acetylcholine receptor(α7 nAChR) in prefrontal cortex and hippocampus area regarding learning and memory abilities in Fmr1 knockout mice. Methods 4-week-old FVB mice were identified by PCR technique and divided into KO blank group(n=16) and WT blank group(n=16), then adopting stepdown test to exam the learning and memory abilities. To detect the expression quantities of α7 nAChR in prefrontal cortex and hippocampus with Western Blotting and immunohistochemistry. The data were analyzed with the Independent-sample T test. Results In step-down test, comparing to WT blank group, on the 1st and 2nd day, the KO blank group were significant shorter in the latent period(P<0.05) and more on the number of mistakes(P<0.05). In imunohistochemistry, the α7 nAChR positive immune cells in the prefrontal cortex and hippocampus of Fmr1 KO blank group have significantly declined(P<0.05), comparing to those of WT blank group.In Western blotting, contrast to the WT blank group, the expression quantity of α7 nAChR in both prefrontal cortex and hippocampus of KO blank group were reduced(P<0.05), and the reduction in the hippocampus was more significant. Conclusion Fmr1 KO mice have low expression quantities of α7 nAChR in the prefrontal cortex and hippocampus comparing to WT mice, which indicates that α7 nAChR involves in the pathogenesis of the deficiency in learning and memory abilities of Fmr1 KO mice.