新生猪缺氧缺血性脑损伤模型纹状体多巴胺转运蛋白PET／CT显像

PET/CT imaging of striatal dopamine transporters in a newborn piglet model of hypoxic-ischemic brain injury

目的利用PET／CT观察新生猪缺氧缺血（HI）性脑损伤纹状体（ST）DAT的变化，探讨DAT在判断HI性脑损伤程度中的价值。方法制备新生猪H1脑损伤模型（n=20），为模型组；另取5头新生猪作为对照组。予猪颈静脉注射C-N-213-甲基酯．3B-（4-氟-苯基）托烷（CFT）55．5～74．0MBq／只，行PET／CT显像，观察新生猪的DAT变化，计算ST／枕叶（OC）比值。模型组按显像时间分为HI后0～6h、20～24h、44～48h、68～72h显像亚组，显像完毕即刻处死各组猪，取大脑行病理分析。采用单因素方差分析和Pearson直线相关分析行数据比较。结果“C—CFT在大脑皮质、小脑及sT放射性分布较高，脑白质放射性分布较低。随着时间延长，大脑皮质、小脑放射性明显减低，而ST显示仍清晰。HI后0～6h，STDAT功能上调，ST／OC比值为1．34±0．04，与对照组比较差异有统计学意义（1．18±0．06，F=4．658，P〈0．05），其余时间组ST／OC比值分别为1．27±0．01、1．27±0．10和1．18±0．05。HI后各时间点病理示DAT免疫阳性神经元数量[（13±3）、（13±4）、（8±3）和（4±4）个／高倍视野]与^11C—CFT PET示ST／OC比值呈正相关（r=0．844，P〈0．05）。结论^11C—CFT PET／CT能够准确反映HI性脑损伤STDAT的动态变化，且DAT的变化与缺血损伤的程度有关。

Objective To investigate changes of striatal DAT following hypoxic ischemic （HI） brain injury in newborn piglets using u C-N-2-carbomethoxy-3-（4-fluorophenyl）-tropane （CFY） PET/CT, and to evaluate the value of u C-CFT PET/CT in brain injury. Methods Newborn piglets with HI brain injury （n =20） were taken as a model group, and five piglets were used as a control group. Radioligand I1C- CFT （55.5 -74.0 MBq） was injected through the jugular vein, and PET/CT imaging was performed to observe the changes of striatal DAT in newborn piglets. The ST/occipital lobe （OC） ratio was calculated. Model group was divided into 0 - 6 h, 20 - 24 h, 44 - 48 h and 68 - 72 h sub-groups after HI in accordance with the imaging time. The piglets were sacrificed immediately after t C-CFT PET/CT scanning, and then the brains were removed for pathological analysis. Data analysis was performed with one-way analysis of va- riance and Pearson linear correlation analysis. Results After intravenous injection of nC-CFI＇, the radioactivity accumulation in cortical, striatum, and cerebellum was shown clearly in the control and model groups. The radioactivity accumulation was lower in the white matter. The radioactivity in cortical and cerebellum exhibited decreased with time, while the striatum was still clear. After HI, the ST/OC activity ratio in the striatum was initially increased, and the ratio of 0 - 6 h group （ 1.34 ± 0. 04） was statistically significant compared with that of thecontrol group （ 1.18 ± 0.06 ; F = 4.658, P 〈 0.05 ）, followed by a gradual decrease. ST/OC ratios of other H1 subgroups were 1.27 ± 0. 01, 1.27 ± 0.10 and 1.18 ± 0. 05, respec- tively. There was a positive correlation between the number of DAT positive neurons （ （ 13 ± 3 ）, （ 13 ± 4）,（8 ±3） and （4 ±4）/high power field） and nC-CFT ST/OC activity ratios （r=0. 844, P 〈0.05）. Conlusion n C-CFT PET/CT study can accurately reflect the changes of DAT in the striatum, and the amount of DAT is related to the severity of the ischemic insult in a newborn piglet model of HI.