高血压大鼠大脑中动脉神经肽Y免疫阳性神经纤维的变化

Changes of Immunoreactive Innervation Containing-NPY on Middle Cerebral Artery in Hypertensive Rats

目的 观察易卒中型肾血管性高血压大鼠 (RHRSP)大脑中动脉神经肽Y(NPY)免疫阳性神经纤维的变化 ,探讨高血压时脑卒中的发生机制。方法 ABC免疫细胞化学方法和体视学技术。结果 (1)脑卒中症状观察 :对照组及高血压组 7d、30d均无脑卒中症状出现 ,但高血压 90d大鼠均出现不同程度的脑卒中症状 ;(2 )定性观察 :对照组大鼠大脑中动脉NPY免疫阳性神经纤维呈网状攀附于血管壁周围 ,分布较均匀 ,并见串珠状膨体 ;高血压组 7d、30dNPY免疫阳性神经纤维的分布与对照组相似 ,但在 90d阳性纤维大片缺失 ,仅见少许环形或纵形纤维 ;(3)定量结果 :对照组各时期NPY免疫阳性纤维的密度无明显变化 ,高血压组 7d、30dNPY阳性神经纤维的密度与对照组无明显差异 ,但 90d纤维的密度较对照组及高血压组 7d、30d明显降低 (P <0 0 1)。结论 高血压大鼠大脑中动脉NPY免疫阳性神经纤维密度降低可能削弱脑血流量自动调节的神经基础 ,与高血压晚期发生脑卒中有关。

Objective To observe changes of NPY-immunoreactive innervation on the wall of middle cerebral artery in stroke-prone renovascular hypertensive rats. Methods By using ABC immunocytochemical and morphometric technique, the immunpositive NPY nerve fibers in the middle cerebral artery were examined. Results 1.There were no symptoms of stroke in control group at 7 d and 30 d in experimental group, but in various symptoms of stroke were emerged at 90 d. 2.Qualitative observation:NPY-immunoreactive innervation, which had a string of varicosities, was reticular and encircled the wall of middle cerebral artery in control group. Although the shape and distribution of NPY-immunoreactive innervation was similar to these of control group at 7 d and 30 d, most of NPY-immunoreactive innervation disappeared, and only few of them could be detected in experimental group at 90 d. 3.Quantitative analysis. The density of NPY-immunoreactive innervation had no substantial changes in control group and at 7 d and 30 d in experimental group. However, the density of innervation decreased significantly at 90 d in experimental group ( P <0.01). Conclusions The decrease of NPY-immunoreactive innervation on the wall of middle cerebral artery might be associated with the development of stroke in hypertension. The mechanism may be related to the injury of autoregulation of cerebral blood flow.