Cerebral blood flow and metabolic changes in hippocampal regions of a modified rat model with chronic cerebral hypoperfusion
Cerebral blood flow and metabolic changes in hippocampal regions of a modified rat model with chronic cerebral hypoperfusion
复制标题
改良慢性脑低灌注大鼠模型海马区脑血流量和代谢变化
DOI：
10.1007/s13760-012-0154-6
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发表时间：
2013-09-01
影响因子：
2.7
通讯作者：
Zhang Gui-Yun
中科院分区：
文献类型：
--
作者：
Hai Jian;Wu Yi-Fang;Zhang Gui-Yun
慢性脑灌注不足（CCH）导致神经退行性变，从而导致认知功能障碍。本研究采用改良的大鼠CCH模型，研究脑血流量（CBF）和海马代谢的变化。采用激光多普勒血流仪测定脑血流量。利用体内质子磁共振波谱（H-1-MRS）从左侧海马区域的选择性感兴趣体积（VOI）中评价各种代谢率。用电镜观察了大鼠海马CA 1区神经元的超微结构变化，特别是核糖体的变化。脑血流量在CCH后立即下降，并在术后1天和3个月仍显着降低。H-1-MRS显示，与假手术对照组相比，模型组大鼠海马VOI区N-乙酰天冬氨酸/肌酸（NAA/Cr）比值明显降低。模型组与对照组相比，肌醇/肌酐、胆碱/肌酐、谷氨酸/肌酐、谷氨酰胺/肌酐比值无明显变化。电镜下，对照组大鼠海马CA 1区神经元胞体中多数呈玫瑰花状分布。CCH后，模型大鼠大多数核糖体聚集成大的异常聚集体。提示慢性脑血管病大鼠认知功能障碍可能与海马区脑血流量的持续性降低和NAA/Cr比值的降低有关。
Chronic cerebral hypoperfusion (CCH) causes neurodegeneration which contributes to the cognitive impairment. This study utilized a modified rat model with CCH to investigate cerebral blood flow (CBF) and hippocampal metabolic changes. CBF was measured by laser Doppler flowmetry. Various metabolic ratios were evaluated from selective volumes of interest (VOI) in left hippocampal regions using in vivo proton magnetic resonance spectroscopy (H-1-MRS). The ultrastructural changes with special respect to ribosomes in rat hippocampal CA1 neurons were studied by electron microscopy. CBF decreased immediately after CCH and remained reduced significantly at 1 day and 3 months postoperatively. H-1-MRS revealed that CCH led to a significant decrease of N-acetyl aspartate/creatine (NAA/Cr) ratio in the hippocampal VOI in the model rats compared with the sham-operated control rats. However, no changes of myo-inositol/Cr, choline/Cr and glutamate and glutamine/Cr ratios between the model and control groups were observed. Under electron microscopy, most rosette-shaped polyribosomes were relatively evenly distributed in the hippocampal CA1 neuronal cytoplasms of the control rats. After CCH, most ribosomes were clumped into large abnormal aggregates in the model rats. Our data suggests that both permanent decrease of CBF and reduction of NAA/Cr ratio in the hippocampal regions may be related to the cognitive deficits in rats with CCH.