不同月龄自发性高血压大鼠杏仁中央核nNOS免疫阳性神经元的变化

Changes of neuronal nitric oxide synthase-immunopositive neurons in the central amygdaloid nucleus of spontaneously hypertensive rats

目的观察自发性高血压大鼠(SHR)杏仁中央核神经元型一氧化氮合酶(nNOS)免疫阳性神经元的变化.方法取SHR和WKY大鼠各30只,分别于90、180和360d测血压并处死,ABC法显示nNOS免疫阳性神经元并进行定量分析.结果WKY大鼠各时期血压无明显差异;SHR血压逐渐升高,而且均高于WKY大鼠(P＜0.05),维持在(20.8±1.1～26.3±1.0)kPa(P＜0.05).杏仁中央核nNOS免疫阳性神经元胞体中等大小,呈梭形或三角形,突起较多且长,阳性神经纤维交错呈网状.定量结果显示,90、180和360d时,WKY杏仁中央核nNOS免疫阳性神经元的数量无显著变化,而SHR大鼠nNOS免疫阳性神经元随着高血压的不断发展呈逐渐减少的趋势,虽然90和180d之间没有显著性差异,但360d减少明显(P＜0.05).结论高血压大鼠杏仁中央核nNOS阳性神经元减少可能通过其对心血管和感觉传递的调节功能参与高血压的发生和发展过程.

Objective To observe the changes of neuronal nitric oxide synthase (nNOS)-immunopositive neurons in the central amygdaloid nucleus of spontaneously hypertensive rats (SHRs). Methods Thirty SHRs and 30 Wistar-Koyto rats (WKYs) were sacrificed at the ages of 90, 180, and 360 days respectively to observe the changes of nNOS-immunopositive neurons with ABC immunocytochemical assay. Results No significant changes were observed in the blood pressure of WKY rats at the specified time points, when SHRs maintained significantly higher blood pressures from 20.8±1.1 and 26.3±1.0 kPa (P<0.05), gradually increasing during the development of hypertension. The nNOS-immunopositive neurons in the central amygdaloid nucleus were of moderate sizes with long intersected nerve fibers. No significant changes were found in WKY rats. The number of the positive neurons decreased with age in SHRs, especially obvious at 360 days (P<0.05), which was significantly different from that in the WKYs (P<0.05). Conclusion The reduction of nNOS-immunopositive neurons in the central amygdaloid nucleus of SHRs might accelerate the development of hypertension by modulating the cardiovascular function and sensory transmission.