生酮饮食对难治性癫痫患儿 Th 细胞亚群的影响

Effects of ketogenic diet on helper T cells in patients with intractable epilepsy

目的：探讨生酮饮食（ketogenic diet，KD）治疗对难治性癫痫（intractable epilepsy，IP）患儿Th细胞亚群的影响。方法 IP患儿35例，同年龄健康对照组18例。采用流式细胞术分别检测外周血CD3＋CD8－IFN-γ＋（Th1）细胞、CD3＋CD8－IL-17A＋（Th17）细胞及CD4＋CD25＋Foxp3＋（Treg）细胞比例；实时荧光定量PCR（real-time PCR）检测外周血CD4＋CD25－T细胞中T-bet、ROR-γt、IFN-γ、IL-17A、过氧化物酶增殖物激活受体γ（peroxisome proliferator-activated receptorγ，PPAR-γ）mRNA及CD4＋CD25＋T细胞Foxp3、GITR、CTLA-4、PPAR-γmRNA的表达；酶联免疫吸附试验（ ELISA）检测受试者血浆中前列腺素F2a （prostaglandin F2a，PGF2a）、环氧化酶-2（cyclooxygenases-2，COX-2）蛋白浓度；流式微球阵列技术（CBA）检测受试者血浆IL-17A、IFN-γ蛋白表达水平。结果（1）IP患儿外周血Treg细胞比例明显低于同年龄健康对照组（P＜0．05），KD治疗后，Treg细胞数量明显增加（P＜0．05）；IP患儿外周血Th1、Th17细胞比例明显高于同年龄健康对照组（P＜0．05），KD治疗后显著下降（P＜0．05）；IP患儿外周血CD4＋CD25＋Treg细胞转录因子Foxp3及相关因子GITR、CTLA-4基因转录水平明显低于健康对照组（P＜0．05），治疗后明显上调；CD4＋CD25－T细胞中T-bet、ROR-γt、IL-17A、IFN-γ等Th1／Th17细胞相关因子表达量显著高于健康对照组（ P＜0．05），治疗后明显下降；（2） IP患儿CD4＋CD25＋及CD4＋CD25－细胞PPAR-γ基因表达明显低于对照组（P＜0．05），KD治疗后表达量明显上升（P＜0．05），相关性分析发现Treg细胞与PPAR-γ表达呈正相关（r＝0．61，P＜0．05），Th1及Th17细胞与PPAR-γ表达呈负相关[Th1（r＝－0．54，P＜0．05）；Th17（r＝－0．64，P＜0．05）]；（3）IP患儿IL-17A及IFN-γ血浆浓度明显高于健康对照组（P＜0．05），KD治疗后明显下降（P＜0．05），COX-2及PGF2a 血浆浓度明显高于正常对照组（P＜0．05），KD治疗后显著下降（P＜0．05），相关性分析发现COX-2表达与PPAR-γ呈负相关（r＝－0．571，P＜0．05），PGF2a表达与PPAR-γ亦呈负相关（r＝－0．586，P＜0．05）。结论 KD可抑制氧化应激反应，降低COX-2及PGF2a蛋白浓度，上调PPAR-γ表达，调节Th细胞亚群紊乱，减少炎症细胞因子产生，这可能是KD治疗IP的作用机制之一。

Objective To investigate the effects of ketogenic diet （ KD） treatment on helper T cell subsets in children with intractable epilepsy（ IP） . Methods Thirty-five children with IP and eighteen age-matched healthy subjects were enrolled in this study.The percentages of CD3＋CD8-IFN-γ＋（ Th1 ） cells, CD3＋CD8-IL-17A＋（Th17） cells and CD4＋CD25＋Foxp3＋（Treg） cells were analyzed by flow cytometry.Re-al-time PCR assay was performed to evaluate the expression of T-bet, ROR-γ, IFN-γ, IL-17A and peroxi-some proliferator activated receptorγ（ PPAR-γ） at mRNA level in CD4＋CD25-T cells and the transcription-al levels of Foxp3, GITR, CTLA-4 and PPAR-γin CD4＋CD25＋T cells.The concentrations of cyclooxygen-ases-2 （COX-2） and prostaglandin F2a （PGF2α） in plasma samples were measured by enzyme-linked im-munosorbent assay.The expression of IL-17A and IFN-γin plasma samples were detected by using cytomet-ricbeadarray（CBA）.Results （1）ThepercentagesofTregcellsinperipheralbloodsamplesfrompa-tients with IP were lower than those in healthy subjects （P〈0.05）, which were significantly increased with the treatment of KD （P〈0.05）.The percentages of Th17 and Th1 cells in patients with IP were significantly higher than those in healthy children （P〈0.05）, but were remarkably decreased with the treatment of KD （P＆lt;0.05）.Patients with IP showed decreased transcriptional levels of Foxp3, GITR and CTLA-4 in CD4＋CD25＋T cells as compared with healthy controls, but were up-regulated with the treatment of KD.The ex-pression of transcription factors including T-bet, ROR-γ, IFN-γand IL-17A in CD4＋CD25-T cells in pa-tients with IP were higher than those in healthy subjects and were down-regulated after the treatment of KD （P〈0.05）.（2） The expression of PPAR-γat mRNA level in CD4＋CD25-T and CD4＋CD25＋T cells were decreased in patients with IP as compared with those in heathy controls, but were increased after the treat-ment of KD （P〈0.05）.Correlation analysis showed that Treg cells had a positive correlation with PPAR-γ（r=0.61, P〈0.05）.However, the Th1 and Th17 cells were negatively correlated with PPAR-γ[Th1 （r=-0.54, P〈0.05）, Th17 （r=-0.64, P〈0.05） ].（3） The levels of IL-17A and IFN-γin patients with IP were higher than those in healthy controls, but were decreased with KD treatment （P〈0.05）.The levels of COX-2 and PGF2αin plasma samples from patients with IP were higher than those in healthy controls （ P〈0.05）.A negative correlation was observed between COX-2 and PPAR-γ（r=-0.571, P〈0.05）. Moreover, PGF2αand PPAR-γhad a negative correlation as well （r=-0.586, P〈0.05）.Conclusion The treatment of KD might enhance the expression of PPAR-γthrough inhibiting the products of oxidative stress such as COX-2 and PGF2α, resulting in the rebalance of Th cell subsets and reduced expression of in-flammatory cytokines.