孕早期大鼠人巨细胞病毒感染对仔鼠海马细胞外信号调节蛋白激酶通路的影响

Effect of Human Cytomegalovirus Infection in Rats during Early Pregnancy on Extracellular Signal-Regulated Protein Kinase Pathway in Hippocampus of Rat Offspring

目的观察孕早期大鼠人巨细胞病毒(HCMV)感染对仔鼠海马细胞外信号调节蛋白激酶(ERK)通路的影响,为研究HCMV先天性感染对子代大鼠海马学习记忆损伤的机制及防治HCMV先天性感染导致的学习记忆障碍等神经系统后遗症提供实验依据。方法取8～9周龄雌性SPF级SD大鼠12只,按雌雄=31配对,孕鼠随机分为对照组和实验组,每组6只。于孕第5天实验组孕鼠腹腔内注射100半数组织细胞感染量HCMV悬液0.8 mL,对照组孕鼠腹腔内注射等量的人胚肺成纤维细胞上清液。于出生后30 d每组随机取10只仔鼠,取仔鼠脑组织,采用HE染色观察仔鼠海马齿状回(DG)区颗粒细胞的形态学改变;免疫组织化学法观察仔鼠海马DG区ERK1、ERK2、p-ERK的表达,并应用SPSS 13.0软件进行分析。结果对照组仔鼠海马未见明显的神经元缺失,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;实验组仔鼠海马细胞数减少,组织结构较稀疏,排列紊乱。ERK1、ERK2、p-ERK主要表达于胞核和胞质,阳性部位呈现棕黄色。实验组仔鼠海马DG区的ERK1、ERK2、p-ERK染色强度及平均积分光密度均低于对照组,差异均有统计学意义(Pa<0.01)。结论孕早期HCMV感染可降低仔鼠海马DG区ERK1、ERK2、p-ERK的表达,可能与HCMV先天感染损伤海马的学习记忆功能有关。

Objective To observe the effect of human cytomegalovirus （HCMV） infection during early pregnancy on extracellular signal - regulated protein kinase （ERK） pathway in the hippocampus of rat offspring so as to provide scientific experimental evidence for further research of the mechanisms of congenital HCMV infection on learning and memory injury in rat offspring and the prevention of congenital HCMV infection - induced learning and memory impairment and other neurological sequelae with disabilities. Methods Eight to nine - week - old female specific -pathogen free Sprague -Dawley rats（ n = 12） were matched with male rats（3 ： 1 ）. Pregnant rats were randomly divided into control group and experimental group, and each group contained 6 rats. The pregnant rats in experimental group were intraperitoneally in- jected with 0.8 mL 50 percent tissue culture infective dose HCMV suspension, and pregnant rats in control group were intraperitoneally injec- ted with the same amount of human embryonic fibroblast supernatant on the 5 gestation day. The brain of rat offspring（ n = 10） was obtained 30 days after birth randomly, then the morphology of hippocampus dentate gyrns region was observed by using hematoxylin eosin staining and the expressions of ERK1 ,ERK2 and p- ERK in hippocampus dentate gyrus （DG） region were analyzed by using immunohistochemistry. SPSS 13.0 software was used to analyze the data. Results The number of hippocampus DG region ceils in control group did not reduce, and cells were arranged compact and well - distributed. Nucleus was round or oval and nucleolus was obvious, and chromatin was even, but the number of hippocampus DG region cells in experimental group reduced, and tissue structure was sparsed, cells were arranged in disorder. ERK1, ERK2, p - ERK were mainly distributed in nucleus and cytoplasm, and positive region was brown. The staining intensity and integrated optical density average of ERK1, ERK2 and p -ERK in hippocampus DG region in experimental group were lower than those in control group,which had significant differences（ Pa 〈 0.01 ）. Conclusions HCMV infection during early pregnancy may reduce the expression of ERK1, ERK2 and p - ERK in hippocampus DG region, which may be associated with damage on learning and memory function of hippocampus by congenital HCMV infection.