外源性血栓粒径对大鼠脑血栓损伤的影响

目的探讨外源性同种异体血栓粒径对大鼠脑血栓栓塞性中风脑损伤的影响。方法采用大鼠颈外动脉注射3种粒径(150～178、74～124μm和48～74μm)的同种血栓,制备血栓栓塞性中风模型,以多普勒血流仪观察栓子注入后脑血流的变化,24 h后观察大鼠行为学变化及脑组织病理学变化。结果 3个粒径血栓经颈外动脉注入均可引起局部脑区血流迅速降低到30%以下,随后脑血流均有不同程度的升高,1 h时脑血流分别为37.7%、40.2%和60.2%,24 h后大鼠神经行为学评分升高,分别为2.55、1.75和1.67,结果表明粒径越大引起的脑血流降低程度越大,神经行为学障碍越明显。HE染色表明外源性血栓可使大鼠脑皮层区发生弥漫的、散在的脑梗死。结论脑内注射同种异体血栓降低脑血流和引起大鼠神经行为学障碍的程度与血栓粒径基本呈正相关,继而导致脑组织弥漫的、散在的病理学损伤。

Effect of different sizes of exogenous emboli on the cerebral injury in rats

Aim To present the effect of different sizes of homologues exogenous emboli on the cerebral injury in rats.Methods A 0.5 ml clot suspension with homologues blood emboli in three diameters(150~178 μm,74~124 μm and 48~74 μm) or normal saline was injected to the right internal carotid artery of a rat.Relative regional cerebral blood flow(rCBF) was continuously monitored before and during the first 1 h following emboli injection.Neurological deficit and morphology of brain cortex were tested at 24 h after injection.Results The rCBF was significantly decreased fewer than 30% at once after three sizes of emboli injection.Then,the rCBF increased at various degrees.At 1 h,the rCBF was up to 37.7%,40.2% and 60.2%,respectively.Injection of different sizes of blood emboli in rats also significantly increased the neurological deficit scores to 2.55,1.75 and 1.67 at 24 h after emboli injection,respectively.These results suggested that the bigger the emboli injected,the more decrease of rCBF and more increase of neurological deficit scores induced.HE staining revealed that rats injected with homologues blood emboli had multiple,widespread and sporadic injury in brain cortex but rats in N and NS groups had no injury.Conclusions Injection of three sizes of emboli can lead to significant rCBF decrease,neurological deficit,and brain cortex injury.Basically,the decrease of rCBF and increase of nerurological deficit scores have positive correlation to the size of blood emboli.