早孕期弓形虫感染对大鼠胎盘IL-4、IL-10和IFN-γ表达水平的影响

研究早孕期弓形虫感染对Wistar大鼠胎盘IL-4、IL-10及IFN-γ表达水平的变化,从而探讨弓形虫感染致不良妊娠的分子免疫学机制。将Wistar孕鼠随机分为2组:①对照组12只;②早孕感染组12只。早孕感染组每只孕鼠于妊娠第5天腹腔注射1×105个弓形虫强毒株(RH株)速殖子,对照组不做任何处理。所有孕鼠均于孕19 d颈椎分离处死,无菌获取胎盘,采用实时荧光定量聚合酶链式反应(real-ti me PCR)及酶联免疫吸附测定(ELISA)检测其胎盘IL-4、IL-10及IFN-γ mRNA及蛋白表达水平的变化。结果:①实验组与对照组IL-4、IL-10及IFN-γmRNA相对表达水平分别为(0.006±0.010)、(0.119±0.080)、(0.82±0.354)和(0.596±0.444)、(0.478±0.224)、(0.297±0.180),三者之间均具有显著性差异(P<0.01);②实验组与对照组IL-4、IL-10及IFN-γ蛋白表达水平分别为(4.63±1.26)、(239.24±83.16)、(105.47±67.88)和(2.40±1.33)、(103.03±79.72)、(208.02±74.95),三者之间均具有显著性差异(P<0.01)、(P<0.05)、(P<0.05);③实验组与对照组mRNA水平IFN-γ/IL-4、IFN-γ/IL-10分别为(390.67±264.12)(37.65±21.10)和(1.31±0.96)、(0.79±0.60)两者之间均具有显著性差异(P<0.01);④实验组与对照组蛋白水平IFN-γ/IL-4、IFN-γ/IL-10分别为(176.51±212.95)、(7.26±8.81)和(23.09±12.95)、(0.44±0.21)。两者之间均具有显著性差异(P<0.01)、(P<0.05)。大鼠早孕期弓形虫感染后,胎盘局部Th1型细胞因子表达增高,Th2型细胞因子表达降低,打破了正常妊娠所需的Th1/Th2平衡状态,使平衡倾向于Th1,可能是弓形虫孕期感染致不良妊娠的重要分子机制之一。

Influence of the Toxoplasma gondii infection in rats during early pregnancy on the expression levels of IL-4,IL-10 and IFN-γ in placenta

To investigate the influence of Toxoplasma gondii infection in rats during early pregnancy on the expression levels of IL-4,IL-10 and IFN-γ in order to explore the molecular immunological mechanism for aberrant pregnancy induced by T.gondii infection,24 pregnant Wistar rats were randomly divided into two groups,including control group(n=12)and infected group(n=12),in which the infected group was intra-abdominally injected with 1×105 of living T.gondii RH strain tachyzoites on the 5 th day of gestation,while the control group of rats was un-treated.All the pregnant rats were killed 19 days after gestation and placentae were collected,in which the expression levels of IL-4,IL-10 and IFN-γ in placentae were analyzed by real-time quantitative PCR and ELISA.It was demonstrated that the relative expression levels of IL-4,IL-10 and IFN-γmRNA in the infected group of rats were(0.010±0.006),(0.119±0.080),and(0.820±0.354) respectively;while those of control group were(0.596±0.444),(0.478± 0.224) and(0.297±0.180) respectively,with a significant difference between these two groups(P<0.01).As to the expression levels of proteins of these 3 cytokines,they were(4.63±1.26),(239.24±83.16) and(105.47±67.88) respectively,and those of the control group were(2.40±1.33),(103.03±79.72) and(208.02±74.95) respectively,with significant difference between these two groups(P<0.01,P<0.05,P<0.05).In the infected group,the average RNA expression ratios of IFN-γ/IL4 and IFN-γ:IL-10 were(390.67±264.12) and(37.65±21.10) respectively,but those of the control group were(1.31±0.96) and(0.79±0.60) respectively.As to the average protein expression ratios of IFN-γ/IL-4 and IFN-γ/IL-10,they were(212.95±176.51) and(8.81±7.26) in the infected group,but(23.09±12.95) and(0.44±0.21) in the control group,the difference between these two groups was significant(P<0.01;P<0.05).It is thus concluded that during early pregnancy,the infection with T.gondii increases the expression of Th1 type of cytokines and reduces the expression of Th2 type of cytokines in placenta of the infected rats,resulting to the imbalance of Th1/Th2 cells and the balance of these helper cells is essential for the maintenance of normal pregnancy.This may be one of the important mechanism for T.gondii to induce aberrant pregnancy.