Differential gene expression in heterophils isolated from commercial hybrid and Thai indigenous broiler chickens under quercetin supplementation

Chicken heterophils serve as the first-line defence in chicken innate immunity. The present study aimed to explore the effects of quercetin, a herbal phenolic substance known for its inflammatory modulation, on mRNA expression patterns in chicken heterophils. Isolated heterophils from two genetically distinct chicken lines, hybrid commercial and Thai indigenous chickens, Pradu Hang Dam, were <i>in vitro</i> co-cultured with live intestinal pathogenic <i>Salmonella enteritidis</i> under Phosphate-buffered saline (PBS) or quercetin supplementation. Quantitative real-time RT-PCR was performed to investigate the effects of quercetin on mRNA transcripts of 12 genes. The results showed that heterophils from hybrid chickens treated with quercetin had higher relative expression levels of <i>IL6</i>, <i>IL8L1</i>, <i>IL8L2</i>, <i>IL18</i>, <i>CCL4</i>, <i>LITAF</i>, and <i>MIF</i>. Unlike hybrid chickens, Pradu Hang Dam chickens had down-regulation of cytokine genes, <i>IL1B</i>, <i>IL6</i>, <i>IL8L1</i>, <i>IL8L2</i>, <i>IL12B</i>, and <i>IL18</i>, and chemokines, <i>CCL4</i> and <i>MIF</i>. In addition, <i>NOS2, IL17A</i>, and <i>TGFB1</i> were up-regulated in this lineage. In conclusion, our findings emphasize the modulatory effects of quercetin to down-regulate most pro-inflammatory genes, whereas it up-regulates anti-inflammatory gene (<i>TGFB1</i>) in Pradu Hang Dam chickens.

鸡异嗜性粒细胞（heterophils）是鸡先天性免疫的第一道防线。本研究旨在探究槲皮素（quercetin）——一种已知可调节炎症反应的草本酚类物质——对鸡异嗜性粒细胞mRNA表达谱的影响。
本研究从两个遗传背景各异的鸡群——商业化杂交鸡与泰国本土品种Pradu Hang Dam鸡——中分离异嗜性粒细胞，将其在磷酸盐缓冲液（PBS）或添加槲皮素的环境中，与活体肠道致病性肠炎沙门氏菌（Salmonella enteritidis）进行体外（in vitro）共培养。采用实时定量逆转录聚合酶链反应（quantitative real-time RT-PCR），探究槲皮素对12个基因mRNA转录本的影响。
结果显示，经槲皮素处理的商业化杂交鸡的异嗜性粒细胞中，白细胞介素6（IL6）、IL8L1、IL8L2、白细胞介素18（IL18）、趋化因子配体4（CCL4）、脂多糖诱导的肿瘤坏死因子-α（LITAF）及巨噬细胞移动抑制因子（MIF）的相对表达水平更高。与商业化杂交鸡不同，Pradu Hang Dam鸡的细胞因子基因[白细胞介素1β（IL1B）、IL6、IL8L1、IL8L2、白细胞介素12B（IL12B）及IL18]及趋化因子（CCL4与MIF）均出现表达下调。此外，该鸡群中诱导型一氧化氮合酶（NOS2）、IL17A及转化生长因子β1（TGFB1）的表达出现上调。
综上，本研究结果证实，槲皮素具有炎症调控作用：在Pradu Hang Dam鸡中，槲皮素可下调多数促炎基因的表达，同时上调抗炎基因转化生长因子β1（TGFB1）的表达。