褪黑素对新生儿脐带血单个核细胞产生细胞因子的影响

Effects of melatonin on the cytokines production of neonatal cord blood mononuclear cell

目的探讨褪黑素（melatonin，MLT）对新生儿脐带血单个核细胞（cord blood mononuclear cells，CBMC）产生细胞因子的影响。方法体外培养10例健康足月新生儿CBMC，取10例健康成人外周血单个核细胞（peripheral blood mononuclear cells，PBMC）作正常对照，不同浓度MLT（50pg／ml-50ng／ml）作为刺激物与CBMC或PBMC共培养，测定培养上清中IL-1β、IL-2、IL-4、IL-6、IL-8、IL-10、IL-12、IFN-γ及TNF-α水平。结果500pg／ml MLT可刺激CBMC产生较高水平的IL-2[（12．18±7．31）pg／ml]、IL-6[（2091．08±968．58）pg／ml]、IL-8[（2779．04±1168．49）pg／ml]、1L-12[（15．29±6．88）pg／m17及IFN-γ[（52．22±17．77）pg／ml]，与对照组[分别为（6．99±4．94）pg／ml、（1017．06±452．60）pg／ml、（1293．33±791．34）pg／ml、（6．84±2．26）pg／ml、（22．24±10．38）pg／ml]相比，差异有统计学意义（P〈0．05）；与对照组[（175．63±62．10）pg／ml]相比，不同浓度MLT（50ng／ml、5ng／ml、500pg／ml、50pg／ml）均可降低CBMC培养上清中TNF—α水平，分别为（24．87±11．21）pg／ml、（18．14±9．44）pg／ml、（31．38±15．28）pg／ml和（28．18±17．35）pg／ml，差异均有统计学意义（P〈0．05）。5ng／ml MLT可诱导PBMC产生IL-2、IL-12及IFN-γ，抑制TNF-α的分泌，与对照组比较，差异有统计学意义（P〈0．05）。比较各自最佳效应浓度的MLT对CBMC（MLT最佳效应浓度为500pg／ml）和PBMC（MLT最佳效应浓度为5ng／ml）释放细胞因子IL-2、IL-12、IFN-γ的诱导作用及对TNF-α的抑制作用，除TNF—α外，差异均有统计学意义（P〈0．01）。结论MLT不但可调节PBMC细胞因子的释放，也可调节CBMC细胞因子的释放，且MLT对CBMC分泌细胞因子IL-12、IFN-γ等的调节作用强于其对PBMC的作用。因此，MLT有可能提高新生儿的免疫功能，为临床应用提供了实验依据。

Objective To investigate the effects of melatonin （MLT） on the eytokines production of neonatal cord blood mononuelear cells （CBMC） in vitro. Methods Ten blood specimens from placenta vena umbilicalis of 10 healthy term delivery newborns were obtained, and 10 healthy adult volunteers＇ peripheral blood mononuclear cells （PBMC） specimens were taken as controls. CBMC and PBMC suspensions were cultivated in the system without serum and hormone, and then 200 /J PBMC/CBMC suspensions （2 ×10^5 cells） were co-cultured with MLT with different concentrations （50 ng/ml, 5 ng/ml, 500 pg/ml, 50 pg/ml） for 72 hours. The concentrations of cytokines including IL-1β, IL-2, IL-4, IL-6, IL-8, IL-12, IFN-γ and TNF-α in the cell supernatant were detected. Results The 500 pg/ml MLT induced secretions of IL-2 [（12.18±7.31） pg/ml], IL-6 [（2091.08±968. 58） pg/ml], IL-8 [（2779.04±1168.49） pg/ml], IL-12 [（15.29±6.88） pg/ ml] and IFN-γ [（52.22± 17.77） pg/ml] of CBMC were more than those of the control group, which were （6.99±4.94） pg/ml, （1017.06±452.60） pg/ml, （1293.33±791.34） pg/ml, （6.84±2.26） pg/ml and （22. 24±10. 38） pg/ml （P〈0. 05）. Compared with control group [（175. 63±62. 10） pg/ ml], all concentrations of MLT could inhibit the TNF-α secretion [ （24.87 ± 11.21） pg/ml, （18. 14± 9.44） pg/ml, （31.38 ± 15.28） pg/ml and （28. 18±17.35） pg/ml] of CBMC significantly. The 50 ng /ml MLT could induce the PBMC＇s secretion of IL-2, IL-12, IFN-γand inhibit the secretion of TNF-α. The best effect of MLT on CBMC was at the concentration of 500 pg/ml, while that on PBMC was 5 ng/ml. Comparing the best effects of MLT, the levels of IL-12 and IFN-γ of CBMC were higher than those of PBMC, and IL-2 level of CBMC was lower than that of PBMC （P〈0.01）. Conclusions MLT could promote the cytokine secretion of PBMC and CBMC, and the effects of MLT on IL-12 and IFN-γ secretion of CBMC were stronger than those of PBMC. The results suggested that MLT may contribute to promote the immune function in newborn infants, and provide experimental evidence for clinical application of MLT.