脑室注射链脲佐菌素对大鼠空间学习记忆能力及海马CA1区神经元数量和海马突触素表达的影响

The effect of intracerebroventricular injection of streptozotocin on rat spatial learning/memory,the number of hippocampal CA1 neurons and the expression of hippocampal synaptophysin

为了观察脑室内注射链脲佐菌素(streptozotocin,STZ)对大鼠空间学习记忆能力的影响,分析其可能的内在机制,本实验选用40只SD大鼠随机分成对照组和模型组,模型组于第1 d和第3 d脑室注射STZ(总量3 mg/kg)建立Alzheimer病(AD)模型,15 d后进行Morris水迷宫试验,利用RT-PCR方法检测突触素(synaptophysin,SYP)mRNA的表达变化;Nissl染色观察海马结构的改变。结果显示:与对照组相比,脑室注射STZ后大鼠平均上台潜伏期明显延长,穿越平台次数明显减少,靶象限游泳时间的百分比降低,SYP mRNA的表达明显减少,Nissl染色见海马CA1区神经元减少。以上结果提示脑室注射STZ可损伤大鼠的空间学习记忆能力,这可能与海马CA1区神经元和突触结构的损伤有关。

To investigate the effect of intracerebroventricular （ICV） injection of streptozotocin （STZ） on the spatial learning/memory and to analyze the possible mechanisms, a total of 40 SD rats were randomly divided into control and model groups. The Alzheimer＇s disease （AD） model was established by ICV injection of STZ bilaterally on the first and third day at a total dose of 3 mg/kg. Cognitive perform- ance was assessed using Morris water maze task 15 days later, then the expression of synaptophysin （SYP） mRNA was measured with RT- PCR and the neural structure of hippocampi was observed with Nissl staining. The results showed that compared with the control group, the mean escape latency of model rats was significantly longer and the number of crossing the platform and percentage of time spent in the target quadrant was significantly decreased. Meanwhile, the impaired spatial learning/memory was accompanied with downregnlated expression of SYP mRNA as well as the reduced number of neurons in the hippocampal CA1 area. Our data suggest that ICV injection of STZ could impair cognitive ability in rat, which might be related with damage of synaptic structures and neurons. Key words streptozotocin, intracerebroventricular, Alzheimer＇s disease, synaptophysin, rat