Department of Neonatology, Guangzhou Children's Hospital, Guangzhou Medical College, Guangzhou, 510120, China.
World J Pediatr. 2009 Nov;5(4):300-3. doi: 10.1007/s12519-009-0057-7. Epub 2009 Nov 13.
Pineal melatonin (MLT) is a neuroendocrine hormone that possesses a wide variety of biological effects. MLT regulation of the immune system has been studied in recent years. But very little is known about MLT interaction with neonatal cord blood mononuclear cells (CBMCs) and the lymphocyte immune system in neonates. This study was designed to investigate the proliferative effects of MLT on CBMCs and peripheral blood mononuclear cells (PBMCs).
Cord blood samples were collected from 10 normal full-term infants at the Guangzhou Maternal and Infant Hospital, China. Ten samples of adult peripheral blood were also collected from healthy volunteers. (3)H-thymidine ((3)H-TdR) incorporation was used to analyze the influence of MLT on proliferation of CBMCs. The effects of MLT on proliferation of CBMCs and PBMCs were compared.
(3)H-TdR incorporation increased in a dose-dependent manner with varying MLT concentrations (50 pg/ml-50 ng/ml), but peaked at 5 ng/ml. After incubation with MLT (5 ng/ml), interleukin-2 (IL-2, 50 ng/ml), MLT+phytohemagglutinin (PHA, 5 microg/ml), and MLT+IL-2, respectively in CBMCs media, (3)H-TdR incorporation rates were 114 327+/-52 863, 16 087+/-9006, 118 360+/-59 207, and 17 682+/-7391. Compared to the control cell suspension (14 133+/-8688), (3)H-TdR incorporation rates of the MLT and MLT+PHA groups were significantly increased (t=5.9143, P<0.001; t=5.5078, P<0.001). (3)H-TdR incorporation was not different between the IL-2 and MLT+IL-2 groups (t=0.4983, P>0.05; t=0.9839, P>0.05). PHA treatment (110 397+/- 48 663) presented no difference in (3)H-TdR incorporation compared to the MLT or MLT+PHA groups (t=0.1730, P>0.05; t=0.3286, P>0.05). (3)H-TdR incorporation was significantly greater in CBMCs than in PBMCs cultures after addition of various stimulators to the culture media.
MLT promoted proliferation of PBMCs and also enhanced proliferation of CBMCs. The proliferative effects of MLT were greater on CBMCs than on PBMCs.
松果体褪黑素（MLT）是一种具有多种生物学效应的神经内分泌激素。近年来，人们研究了 MLT 对免疫系统的调节作用。但对于 MLT 与新生儿脐血单个核细胞（CBMCs）和新生儿淋巴细胞免疫系统的相互作用，人们知之甚少。本研究旨在探讨 MLT 对 CBMCs 和外周血单个核细胞（PBMCs）增殖的影响。
收集中国广州妇幼医院 10 名正常足月婴儿的脐血样本，同时收集 10 名健康志愿者的成人外周血样本。采用（3）H-胸腺嘧啶核苷（（3）H-TdR）掺入法分析 MLT 对 CBMCs 增殖的影响。比较 MLT 对 CBMCs 和 PBMCs 增殖的影响。
随着 MLT 浓度（50 pg/ml-50 ng/ml）的增加，（3）H-TdR 掺入呈剂量依赖性增加，但在 5ng/ml 时达到峰值。在 MLT（5ng/ml）孵育后，分别在 CBMCs 培养基中加入白细胞介素-2（IL-2，50ng/ml）、MLT+植物血凝素（PHA，5μg/ml）和 MLT+IL-2，（3）H-TdR 掺入率分别为 114327+/-52863、16087+/-9006、118360+/-59207 和 17682+/-7391。与对照细胞悬浮液（14133+/-8688）相比，MLT 和 MLT+PHA 组的（3）H-TdR 掺入率明显增加（t=5.9143，P<0.001；t=5.5078，P<0.001）。IL-2 和 MLT+IL-2 组之间（3）H-TdR 掺入率无差异（t=0.4983，P>0.05；t=0.9839，P>0.05）。与 MLT 或 MLT+PHA 组相比，PHA 处理（110397+/-48663）的（3）H-TdR 掺入率无差异（t=0.1730，P>0.05；t=0.3286，P>0.05）。加入各种刺激物后，CBMCs 培养物中的（3）H-TdR 掺入量明显高于 PBMCs 培养物。
MLT 促进了 PBMCs 的增殖，也增强了 CBMCs 的增殖。MLT 对 CBMCs 的增殖作用大于 PBMCs。
