摘要
目的利用微透析技术(MD)观察脑室周围白质软化(PVL)早产大鼠脑内氨基酸递质的动态变化,探讨兴奋毒性氨基酸在PVL发生发展中的作用。方法3-硝基丙酸(3-NPA)脑内注射复制5日龄(P5)新生SD大鼠PVL模型(n=32),利用微透析技术,于造模前,造模15、30、45、60、75、90min收集透析液,收集完毕移除设备,实验新生大鼠由母鼠代养至P6～P14。采用高效液相色谱(HPLC)定量分析透析液谷氨酸(Glu)、天门冬氨酸(Asp)、甘氨酸(Gly)、γ-氨基丁酸(GABA)水平,计算其兴奋毒性指数(EI)。16只实验新生大鼠于P6、P7、P8、P14处死,灌注固定取脑,作HE染色观察神经病理学改变。结果微透析分析显示,细胞外液中Glu与Asp水平在造模15～45min升高,明显高于造模前水平(P<0.05),随后恢复到造模前水平;Gly水平在造模15～75min显著升高(P<0.05),90min恢复至造模前水平;GABA水平在造模15～30min明显高于造模前水平(P<0.05),45min后恢复至造模前水平;反映兴奋性神经递质与抑制性神经递质平衡综合指数EI值在造模15～75min明显增高,90min恢复至造模前水平。HE染色显示PVL新生大鼠脑室周围白质出现不同程度疏松、液化,后期出现脑室扩大。结论氨基酸递质在PVL的损伤过程中出现规律性变化:无论是兴奋性氨基酸还是抑制性氨基酸在损伤的早期阶段都出现显著增高,随后恢复至损伤前的水平;反映兴奋性神经递质与抑制性神经递质平衡综合指数的EI值亦表现出同样的规律性。氨基酸兴奋毒性作用在PVL的发生、发展中起重要作用,PVL干预宜在早期阶段。
Objective To observe the changes of intracerebral amino acid transmitters in the periventricular leukomalacia （PVL） of newborn rats with microdialysis and so as to explore the role of excitotoxicity in PVL. Methods Replicated the model for PVL at the age of postnatal day 5 （P5） by intracerebral injection of 3 - nitropropionic acid （ 3 - NPA）. Before injection of 3 - NPA, and 15 min, 30 min,45 min, 60 min,75 min,90 min after injection of 3 - NPA, collected the sample of extracellular fluid （ECF） at the corpus callosum above the left ventricle through microdialysis, respectively. After microdialysis, the experimental rats were allowed to survive to P6 -P14, and then they were killed and the bmins were prepared for HE stain. The amino accids of dialysate were quantified through high performance liquid chromatography（HPLC） ,and then the cxcitotoxic index （EI） was calculated. Results Fifteen min to 45 min after injection of 3 - NPA, the concentrations of glumate （Glu） and aspartic acid （Asp） of ECF elevated significantly, and then returned to the normal levels. Fifteen min to 75 min and 15 min to 30 min after injection of 3 -NPA, the concentrations of glycine （Gly） and GABA significantly elevated, respectively, and returned to normal levels at 90 min and 45 min after injection of 3 - NPA, respectively. But the EI,which indicated the balance of excitatory amino acids （EAAs） and inhibitory amno aciols （ IAAs）, significantly elevated 15 min to 75 min after injection of 3 - NPA, then rctured to normal level after 90 min. Sub - cortical and periventricular white matter rarefaction and significant lateral venmcle enlargement were observed in HE staining. Conclusions Changes of intracerebral amino acid transmitters in the PVL of newborn rats show regularity ： EAAs, IAAs of ECF and El clavate in the early stage, and then return to the normal level quickly. It indicates that excitotoxicity play a great role in PVL, especially at the early stage. Therefore,the preventions of PVL must be executed at the early stage.
出处
《实用儿科临床杂志》
CAS
CSCD
北大核心
2009年第20期1594-1597,共4页
Journal of Applied Clinical Pediatrics
基金
生物电子学国家重点实验室开放研究基金项目资助(680703-9002)
关键词
微透析
兴奋毒性
脑室周围白质软化
兴奋性氨基酸
鼠
早产
microdialysis
excitotoxicity
periventricular leukomalacia
excitatory amino acids
premature rat
