孕早期人巨细胞病毒感染对仔鼠海马N-甲基-D-天冬氨酸受体亚基表达的影响

Effect of N-Methyl-D-Aspartic Acid Receptor in Hippocampus of Offspring Rat Caused by Human Cytomegalovirus Infection during Early Pregnancy

目的探讨孕早期人巨细胞病毒(HCMV)感染对子代SD大鼠海马N-甲基-D-天冬氨酸(NMDA)受体亚基的影响及对仔鼠学习记忆的影响。方法取8周龄SPF级SD雌鼠18只。按雌雄31合笼交配,将受精大鼠随机分为实验组和对照组,每组9只,于妊娠第5天分别腹腔内注射5×107L-1半数组织培养感染量(TCID50)HCMV悬液0.8 mL和等量的人胚成纤维细胞上清液。出生后1个月分别从每组随机抽取10只子代大鼠,取仔鼠脑组织,采用HE染色观察仔鼠海马形态学变化;使用Morris水迷宫评价子代大鼠的学习记忆功能;应用免疫组织化学方法检测大鼠海马组织NMDA受体表达变化。采用SPSS 16.0软件进行统计学处理。结果对照组子代大鼠海马未见神经元缺失,排列紧密,均匀整齐,胞核呈圆形或椭圆形,核仁明显,染色质均匀;与对照组比较,实验组子代大鼠海马有神经细胞坏死、减少、水肿、细胞核消失现象,部分细胞呈巨细胞变;在Morris水迷宫实验中,实验组子代大鼠的学习记忆成绩较对照组明显下降(Pa<0.01);免疫组织化学结果显示实验组子代大鼠海马组织NR1、NR2A及NR2B平均吸光度均较对照组低(Pa<0.01)。结论孕早期HCMV感染可导致仔鼠学习记忆能力受损,可能与其海马区NMDA受体的表达减少有关。

Objective To investigate the influence on learning and memory related to the expression of N-methyl-D-aspartic acid（NMDA）receptor in offspring Sprague-Dawley（SD） mice hippocampus caused by human cytomegalovirus（HCMV） infection during early pregnancy. Methods Eight-week-old female SPF SD mice（n=18）were matched with male rats（31）.Pregnant rats were randomly divided into control group and experimental group, 9 rats in each group.Pregnant rats in the experimental group were intraperitoneally injected 0.8 mL 5×107 L-1 50 percent tissue culture infective dose（TCID50） HCMV suspension,and respectively,the pregnant rats in control group were intraperitoneal injected the same amount of human embryonic fibroblast supernatant on 5 gestation days. The brain tissues of offspring rat（n=10） 1 month after birth were sampled randomly,then observed the morphology of hippocampus by hematoxylin eosin staining;The ability of learning and memory was tested by Morris water;The expression of NMDA receptor in hippocampus was determined by immunohistochemical staining.SPSS 16.0 software was used to analyze all data. Results The number of hippocampus nerve cells in control group did not decrese,cells were arranged compactly and well-distributed,nucleus was round or oval,nucleolus was observed,and chromatin was even;while in the control group,the pathological changes were detected in infected group under light microscope,such as degeneration,necrosis,edema and nucleus disappearance of nerve cells and giant cells. In Morris water test,learning and memory dysfunction were observed in infected group（Pa〈0.01）;In immunohistochemical staining,relative absorbance of NR1,NR2A,NR2B receptor decreased significantly in infected group（Pa〈0.01）. Conclusions The infection induced by HCMV during early pregnancy can result in damages of learning and memory functions in offspring rat,which might be reletated to its regulating effect on expression of NMDA receptor in hippocampus.