慢性缺血性痴呆大鼠大脑皮层及海马中 HO-1、VEGF表达的变化

目的：探讨慢性缺血性痴呆大鼠学习记忆能力及大脑皮层和海马中血管内皮生长因子（V EG F ）、血红素氧化酶‐1（HO‐1）蛋白表达的变化。方法将健康Wistar大鼠36只分为对照组、假手术组和模型组，每组12只。以大鼠永久性双侧颈总动脉阻断建立慢性缺血性痴呆大鼠模型，假手术组除不结扎双侧颈总动脉外，其他的处理同模型组。1、4、8、12周进行Morris水迷宫实验和攀绳肌力实验来判定大鼠的学习和记忆能力；用免疫组化SP法在光镜下观察各组大鼠大脑皮层和海马中VEGF和H O‐1蛋白的表达。结果8、12周模型组逃避潜伏期时间长于假手术组和对照组，跨过平台所在位置的次数少于假手术组和对照组，差异均有统计学意义（P＜0．05）；1～12周模型组与假手术组、对照组动物攀附的时间比较，差异均无统计学意义（P＞0．05）；对照组、假手术组HO‐1、VEGF蛋白量阳性表达均少于模型组，差异均有统计学意义（P＜0．05）。结论慢性脑灌注不足对大鼠学习记忆能力具有永久性的损伤作用，而对运动功能无明显影响。VEGF和HO‐1可能在慢性脑缺血中发挥神经保护作用。

Changes of VEGF and HO-1 expression in cerebral cortex and hippocampus of chronic ischemic vascular dementia rat

Objective To investigate the changes of learning and memory function ,vascular endothelial growth factor (VEGF) and heme oxygenase‐1(HO‐1) expression in cerebral cortex and hippocampus of chronic ischemic vascular dementia rats . Methods Thirty‐six healthy SD rats were divided into the control group ,sham operation group and model group ,12 cases in each group .The chronic ischemic vascular dementia rat model was established by the permanent bilateral carotid artery occlusion The sham operation group received the same treatment to the model group except without bilateral carotid artery occlusion .The learning and memory abilities were tested by the Morris water maze experiment and climbing rope strength experiment at 1 ,4 ,8 ,12 weeks respectively .The expressions of VEGF and HO‐1 in rat cerebral cortex and hippocampus was determined by immunohistochemical SP technique .Results The escape latency time at 8 ,12 weeks in the model group was longer than that in the sham operation group and control group ,and the number of crossing the platform was less than that in the sham operation group and control group ,the differences were statistically significant (P<0 .05);the time of climbing at 1 -12 weeks had no statistical difference between the model group and the sham operation group and between the model group and the control group (P>0 .05) .The positive expression of HO‐1 and VEGF protein contents in the control group and sham operation group was less than that in the model group with sta‐tistical difference(P<0 .05) .Conclusion Chronic cerebral hypoperfusion has a permanent damage to the learning and memory abil‐ities in rats ,while has no influence on the motor function .VEGF and HO‐1 may play a protective role in chronic cerebral ischemia .