新生儿脐血Toll样受体变化及其意义

Expression and significance of Toll-like receptors in cord blood mononuclear cells

目的观察新生儿脐血单个核细胞(MNC)TLR4、TLR2 mRNA 的表达。方法将46例无窒息新生儿及40例窒息新生儿根据胎龄分组,分离脐血 MNC,测定其 TLR4/2 mRNA 表达及上清中 TNF-α水平。另外将 TLR4/2 mRNA 表达水平与 TNF-α水平进行相关分析。结果无窒息新生儿中足月儿TLR4/2 mRNA 及 TNF-α水平分别为0.75±0.12、0.63±0.08、2502.6±273.1 ng/L,胎龄≥32周但<37周早产儿分别为0.37±0.04、0.32±0.03、1218.8±145.7 ng/L,胎龄<32周早产儿分别为0.26±0.03、0.20±O.03、811.8±105.2 ng/L;窒息新生儿中足月儿 TLR4/2 mRNA 及 TNF-α水平分别为0.58±0.07、0.50±0.06、1946.4±244.2 ng/L,胎龄≥32周但<37周早产儿分别为0.29±0.03、0.26 0.03、970.0±94.3 ng/L,胎龄<32周早产儿分别为0.17±0.02、0.14±0.02、652.6±60.3 ng/L;成人 TLR4/2 mRNA 及 TNF-α水平分别为2.71±0.75、2.61±0.33、9270.1±1098.3 ng/L。早产儿、足月儿 TLR4/2 mRNA 及 TNF-α水平均低于成人,胎龄越低,TLR4/2 mRNA 及 TNF-α水平越低。窒息新生儿 TLR4/2 mRNA 及 TNF-α的表达水平均低于同胎龄无窒息新生儿(P<0.01)。TLR4/2 mRNA 表达水平与 TNF-α水平呈正相关关系。结论新生儿,特别是早产儿,TLR 水平低下,可能是新生儿天然免疫能力低下,容易患败血症等严重感染性疾病的重要原因之一。

Objective To investigate the expression of TLR4/2 mRNA in neonatal cord blood mononuclear cells （MNC） . Methods Forty-six neonates without asphyxia and 40 neonates with asphyxia were divided into groups depending on the gestational age. In the neonates without asphyxia, there were 18 full term infants （the gestational age ≥37 weeks）, 16 preterm infants whose gestational age was ≥32 weeks but 〈 37 weeks, and 12 preterm infants whose gestational age was 〈 32 weeks. In the neonates with asphyxia, 11 were full term infants, 15 were preterm infants whose gestational age was ≥32 weeks but 〈 37 weeks and 14 were preterm infants at gestational age 〈32 weeks. MNCs were separated and cultured with LPS （1 μg/ml） for 3 h. Cells were collected for analysis of gene expression of TLR4/2 by RT-PCR technique. Cell supematants were taken to measure TNF-α production following the ELISA pretocol. Fifteen healthy adults were enrolled into the control group. In addition, the Pearson correlation analyses were carried out between the levels of TLR4, TLR2 mRNA and the levels of TNF-α. Results In the neonates without asphyxia, TLR4, TLR2 mRNA and TNF-ot levels were 0. 75 ±0. 12, 0. 63 ±0. 08, 2502.6 ±273.1 ng/L, separately, in the full term infants, 0. 37 ± 0. 04, 0. 32 ± 0. 03, 1218.8 ± 145. 7 ng/L, separately, in the preterm infants whose gestational ages were ≥ 32 weeks but 〈 37 weeks, and 0. 26 ± 0. 03, 0. 20 ± 0. 03, 811.8 ± 105.2 ng/L separately, in the preterm infants whose gestational ages were 〈 32 weeks. In the neonates with asphyxia, TLR4, TLR2 mRNA and TNF-α levels were 0. 58 ±0. 07, 0. 50 ±0. 06, 1946.4 ± 244. 2 ng/L, separately, in the full term infants, 0. 29 ± 0.03, 0. 26 ± 0. 03, 970. 0 ± 94. 3 ng/L, separately, in the preterm infants whose gestational age was ≥32 weeks but 〈37 weeks, and 0. 17 ±0. 02, 0. 14±0. 02,652. 6 ±60. 3ng/L, separately, in the preterm infants whose gestational age was 〈32 weeks. The levels of TLR4, TLR2 mRNA and TNF-α in the adults were 2. 71 ± 0. 75, 2. 61 ± 0. 33, 9270. 1 ± 1098.3 ng/L, separately. In the preterm infants and full term infants, the levels of TLR4, TLR2 mRNA and TNF-αwere lower in comparison to the adults. The lower the gestational age, the lower the levels of TLR4, TLR2 mRNA and TNF-α. There were significant differences between the levels of TLR4, TLR2 mRNA and TNF-α of the neonates without asphyxia and those of the neonates with asphyxia. In the neonates with asphyxia, the levels of TLR4, TLR2 mRNA and TNF-α were lower than those in the neonates without asphyxia （ P 〈 0. 01 ）. Whether the neonates were asphyxic or not, the levels of TLR4, TLR2 were paralleled with the levels of TNF-α. Conclusions The expression of TLRs in the neonates, especially in the preterm infants was lower than that in the adults, which probably contributes to the susceptibility of neonates to infections.