大鼠脑出血模型血肿周围继发损害机制的实验研究

目的探讨大鼠出血模型在血肿形成的不同时间点血肿周围脑血流指标的变化情况,证实血肿周围的局灶性缺血可导致血肿周围的继发性损害.方法选用SD大鼠50只,制备脑出血模型.分别于注血/盐水后1、6、24、48及72h 5个时间点对大鼠脑出血模型进行动态CT灌注成像扫描,获得脑血流参数,计算脑组织水含量.对血肿周围区脑血液动力学参数进行方差分析,对血肿周围水含量进行相关性分析.结果血肿周围组织与对照组比较,注血组血肿周围脑组织rCBF和rCBV降低,MTT延长(P＜0.05).血肿脑周围组织水含量在注血后24h最高,并延续至72h;而注血后1h周围脑组织rCBF、rCBV显著低于注血后24、48和72h组(P＜0.05).血肿周围组织脑水含量与血肿周围rCBV呈正相关.结论血肿周围局部脑血流的变化可引起血肿周围组织缺血损伤,但血肿周围缺血下降峰值时间和水肿严重程度峰值明显不一致,提示脑出血后周围水肿继发损害因素可能为非缺血单一因素,而是存在多种复杂因素.

Study of the mechanism of secondary injury to the perihematoma region in rats

Objetive To investigate the blood flow parameters (rCBV, rCBF, MTT) in perihematoma region at different time intervals after hematoma formation in rats in vivo and to identify the secondary injury to perihematoma area as a result of regional ischemia. Methods 50 SD rats were subjected to cerebral hemorrhage models. Dynamic CT perfusion imaging was carried out to measure the parameters of cerebral blood flow at 1, 6, 24, 48 and 72h in rats with blood injection and saline injection respectively. Then the water content of brain tissue was calculated. ANOVA statistic analysis for the brain hemodynamic parameters of perihematoma and correlation analysis for water content of the same affected region were carried out. Results Hypoferfusion was detected at perihematoma tissue in different extent rats with blood injection had shown lower rCBF, rCBV and longer MTT at perihematoma tissue compared with the control group(P<0.05). The water content of perihematoma tissue reached its peak 24h after blood injectionand and lasted for 72h; the rCBF and rCBV of perihematoma tissue at 1h were much lower than that at 24, 48, 72h in rats after blood injection(P<0.05). There was positive correlation between water content of perihematoma brain tissue and rCBV of the same region. Conclusions Decreased regional cerebral blood flow which may induce perihematoma tissue ischemic injury has been identified by cerebral haemorrhage model in rats. It is one of the major causes of secondary injury to the perihematoma area. However, the remarkable unmatched drop of peak time of ischemia and the degree of oedema suggest that many complicated reasons are responsible for the oedema of perihematoma.