失血性休克大鼠中脑导水管周围灰质腹外侧区一氧化氮合酶阳性神经元的变化

Changes of the NOS-Positive Neurons of the Ventrolateral Region of the Midbrain Periaqueductal Gray in Hemorrhagic Shock in Rats

目的观察失血性休克大鼠中脑导水管周围灰质(PAG)腹外侧区的一氧化氮合酶(NOS)阳性神经元的变化。方法取雄性SD大鼠20只随机分成4组,即对照组(假手术组)、休克时组、休克45 min组和休克90 min组。对照组仅进行左股动脉插管而不放血;其他各组经左股动脉插管放血复制失血性休克模型。分别在休克时、休克45 min和休克90 min灌注固定后取脑干进行冰冻切片,行NADPH-d组化染色观察,并对各组PAG腹外侧区尾段的NOS阳性神经元和其背内侧NOS阳性突起密度进行比较。结果PAG腹外侧区尾段的NOS阳性神经元密度的变化无统计学意义(P>0.01),但在失血性休克后NOS阳性神经元染色明显加深,其背内侧突起增密,变化有统计学意义(P<0.01)。结论大鼠PAG腹外侧区的NOS阳性神经元可能参与了失血性休克的发生发展,并且发挥着影响。

Objective The study is to expose the significance of the NOS-positive neurons in the ventrolateral region of the midbrain periaqueductal gray （PAG） to the development and progress of hemorrhagic shock by observing their changes in rats. Methods Twenty male Sprague-Dawley rats were randomized into four groups, five in eachgroup. After femoral arterial catheterization, in group one, the control animals were perfused and fixed; other groups were bled to hemorrhagic shock by femoral arterial catheter, then were perfused and fixed at 0 min, 45 min, 90 min after shock, respectively. The brain stems of all rats were sectioned in a cryostat. Then the sections were stained by NADPH- d histochemical method. The density of the NOS-positive neurons in the ventrolateral region of the caudal part of the PAG was surveyed, as well the NOS-positive nerve fibers and axon terminals in the dorsomedial region of the later. The experimental data were analyzed by analysis of variance （completely random design）. Results Though there were no significant changes of the density of the NOS-positive neurons in the ventrolateral region of the caudal part of PAG between the control group and each of experimental groups, the NOS-positive neurons of the experimental groups were stained much deeper than that in the control group. And in the dorsomedial region of the ventrolateral region of the caudal part of PAG, the density of the NOS-positive nerve fibers and axon terminals was significantly higher in group three and four than that in the control group（P 〈 0.01 ）. Conclusion The NOS-posirive neurons in the ventrolateral region of PAG may play important roles in the development and progress of hemorrhagic shock by many ways.