多光谱光学成像在小鼠缺血性脑卒中神经血管功能评估中的应用

Evaluation of neurovascular function in mouse cortex using multispectral optical imaging after ischemic stroke

目的观察小鼠缺血性脑卒中后缺血灶周神经血管光学特征改变,探究神经血管光学信号改变与疾病损伤程度的相关性。方法选6~8周龄、体质量20 g雄性C57BL/6野生型小鼠,标记神经元在缺血性脑卒中建模后1、3和7 d用多光谱光学成像监测小鼠缺血灶周神经元和血氧在电刺激下的光学信号(n=20);测量小鼠(n=30)脑卒中后梗死灶体积、血浆肿瘤坏死因子-α(TNF-α)浓度和改良神经功能缺损评分(mNSS),分析其与光学信号之间的关系。结果小鼠脑卒中后1、3和7 d,缺血灶周神经元兴奋性信号响应幅度为1.15%±0.28%、2.84%±1.06%、2.21%±0.55%;总血红蛋白浓度响应幅度为3.71%±2.76%、3.19%±2.70%、4.27%±3.05%;脱氧血红蛋白浓度响应幅度为2.93%±2.33%、3.60%±1.74%、2.08%±1.28%。神经元兴奋性信号与梗死灶体积、血浆TNF-α浓度及mNSS负相关(r=-0.441,-0.449,-0.404,均P<0.05),mNSS对神经元兴奋性信号改变影响显著(β=-0.169,P<0.05);总血红蛋白浓度信号与梗死灶体积正相关(r=0.440, P<0.05)。结论多光谱光学成像能观测脑缺血灶周神经元活动及血氧信号变化,并可评估疾病损伤程度。

Objective To acquire the signal of neuron excitability and blood oxygen in mouse cortex after ischemic stroke, and to clarify the relationship between the change of neurovascular function and the degree of cerebral infarction. Methods The male C57BL/6 mouse(n=20) about 6-8 weeks and 20 g weight were produced the embolic stroke modal by photochemical injury. The mouse cortex was scanned by the multispectral optical imaging while using electric stimulation in 1, 3 and 7 d after operation. Then several data around the infarction were acquired including neuron excitability, the total hemoglobin concentration and deoxygenated hemoglobin concentration. The ischemic cerebral infarction size was analyzed by TTC staining. Plasma TNF-α concentration was measured by enzyme-linked immunosorbent assay(ELISA). And modified neurological severity score (mNSS) was recorded after ischemic stroke(n=30). Then correlativity analysis was used between the optical signals and three indicators of cerebral infarction degree. Results The changes of neuron excitability signals were 1.15%±0.28%, 2.84%±1.06%, 2.21%±0.55%. The total hemoglobin concentration signals were 3.71%±2.76%,3.19%±2.70%,4.27%±3.05%. The deoxygenated hemoglobin concentration signals were 2.93%±2.33%, 3.60%±1.74%, 2.08%±1.28%. The neural signal was correlated to cerebral infarction size, plasma TNF-α concentration and mNSS(r=-0.441,-0.449,-0.404, all P<0.05), and mNSS had a great effect on neuron excitability(β=-0.169,P<0.05). Meanwhile, the total hemoglobin concentration was correlated to cerebral infarction size(r=0.440,P<0.05). Conclusion The signal of neuron and blood oxygen is able to represent the change of neurovascular function and evaluate the progression of ischemic stroke.