捆绑并倒悬复合刺激大鼠海马CA3区神经肽Y和Nestin的变化

【目的】应用改良的连续、恒定复合型应激大鼠模型，观察其血浆肾素活性（PRA）、血管紧张素Ⅱ（AngⅡ）水平和海马CA3区的Nestin、NPY表达。【方法】将雌性成鼠束缚并倒悬应激6h/d，用放射免疫法测定急性应激(3d)后血浆PRA、AngⅡ水平，用免疫组织化学方法观察应激3d、21d后CA3区锥体层细胞的Nestin、NPY表达变化。【结果】①急性应激组血浆PRA和AngⅡ水平比正常对照组显著降低（P<0.01），尤其是PRA水平的变化最明显。②急、慢性应激组海马CA3区的Nestin、NPY免疫阳性反应产物总面积（SA）和体视学光密度（IOD）值均较对照组低（P<0.01），急性组的组织损害比慢性组更严重。【结论】本研究成功地构建了具有科学理论依据和实用价值的复合性应激大鼠模型，并利用此模型研究证实应激早期大鼠血浆PRA水平的降低；以及急、慢性应激大鼠的NPY、Nestin和NF200表达变化及其变化规律，结果提示NPY及其水解产物在应激所致海马神经元细胞骨架损害和谷氨酸释放过程中可能产生一定的影响。

Neuropeptide Y and nestin expression in the hippocampal CA3 region following restrained and inverted stress in rats

Our preliminary study demonstrated that neuropeptide Y (NPY)/nestin-positive cells exhibit a consistent spatial distribution in the hippocampus of normal adult rats. However, following severe acute and chronic stress-induced impaired learning and memory, synchronous decreased expression of nestin and NPY takes place in the hippocampus, and the underlying mechanisms remain unclear. In the present study, acute and chronic stress rat models were established using combined restrained and inverted stress. Results showed that learning and memory significantly decreased in acute and chronic stress rats. In addition, hippocampal cells were damaged, in particular in the acute stress rats, and nestin and NPY expression, as well as the number of NPY/nestin-positive cells in the CA3 region, significantly decreased. Furthermore, mature neurofilament 200-positive neurons were absent in the chronic stress rats. The NPY and cytoskeletal protein system equally contributed to stress-induced early learning and memory deficits, as well as sustained cerebral injury in the adult hippocampus.