急性低氧大鼠脑^(31)P核磁共振波谱研究

STUDY OF ^(31)P NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY IN ACUTE HYPOXIC BRAIN OF RAT

31 P磁共振波谱是目前唯一可以用作在体无损伤的检测细胞水平能量代谢变化的非侵入性技术 ,可测得脑内多种能量代谢产物 .目的 :急性低氧大鼠脑组织的31 PMRS检测 .方法 :(1 ) 2 0只成年SD大鼠分为 4组 :低氧 0min(对照 ) ,5min ,1 0min ,1 5min后 ,迅速液氮冷冻 ;(2 )将脑组织研碎后 ,加入高氯酸 (PCA) ,冷冻干燥 ;(3)将提取物用 0 .5mLD2 O溶解后进行MRS检测 .结果 :(1 )急性低氧早期即引起31 PMRS中PCr和ATP峰降低 ,ADP和Pi峰增高 ,PCr/Pi和ATP/Pi降低 ,而ADP/ATP增高 .可交换磷池 (EPP)中PCr的正常值为 42 .4% ,低氧 5min后降到 2 8.9% ,ATP从 33.8%降到 1 9.2 % ,Pi从 1 7.7%升到 42 .0 % .(2 )急性低氧时31PMRS中脑内磷酯分解代谢产物GPC、GPE含量增加 ,说明低氧早期脑内即有膜磷酯的分解增加 .结论 :31 P磁共振波谱可用于脑低氧性疾病的诊断 ,我们波谱中最敏感的指标是PCr/Pi和ATP/Pi,尤其早期降低更为显著 .

Nuclear magnetic resonance spectroscopy (MRS) is a unique scatheless noninvasively method to detect the metabolism of brain in cell level on living body. {}+{31}P MRS is used to check and measure the content varieties of manifold metabolites in brain.;Purpose:Study of {}+{31}P MRS in acute hypoxic brain of rat.;Materials and methods:(1) Twentyl adult male SD rats suffered from hypoxic experiments were divided into four groups -0min(control), 5min,10min,15min. Then the brains were quickly frozen with liquid N-2 and the whole brains were removed and restored in liquid N-2. (2) The frozen brains were pulverized to a fine powder with a stainless steel mortar and pestle chilled with liquid N-2. Then perchloric acid (PCA) were added into the tissue powder, and the extract were lyophilized. (3) The extracts were dissolved in 0.5mL D-2O for MRS analysis.;Results:(1) Hypoxia reduced the densities of high-energy phosphates (ATP,PCr) and increased content of Pi. The ratio of PCr/Pi and ATP/Pi lowered and ADP/ATP raised. In exchangeable phosphate pool(EPP), the normal value of PCr was 42.4%, after 5min hypoxia episode, it decreased to 28.9%, ATP decreased from 33.8% to 19.2%, and Pi increased from 17.7% to 42.0%. (2) Hypoxia increased the content of GPC and GPE, which were metabolites of phospholipid resolved.;Conclusion: {}+{31}P MRS of PCA extracts suit the study of energy metabolism and phospholipid metabolism of brain. Acute hypoxia lead to some obvious varieties of the spectroscopy, and the notable varieties were PCr/Pi and ATP/Pi. This may be used to diagnose the disease of hypoxia or ischemia.;