出生至断奶仔猪胃肠道组织中FcRn的表达规律初探

Expression of Neonatal Fc Receptor in the Gastrointestinal Tractof Piglets from Birth to Post-weaning

【研究目的】旨在研究FcRn在仔猪胃肠道的表达分布及不同日龄间的表达变化。【方法】以大白和长白二元杂交仔猪作为研究对象,分布采集从出生至断奶后共12个日龄仔猪胃肠道组织,应用RT-PCR方法检测FcRn mRNA表达并进行表达量的相对分析。【结果】①FcRn在仔猪胃肠道各段组织中均有表达,其中在十二指肠后段和空肠前段表达量最高,在结肠和胃内表达最低。②在十二指肠和空肠段,仔猪从一出生就有较高水平的FcRn转录,吮乳后至出生后1d达到峰值,随后略有下降但前4d差异不显著(P>0.05);自7d起FcRn mRNA转录水平明显降低(P<0.05),至断奶时降到最低。③在回肠段,FcRn表达水平较十二指肠和空肠段低,从出生至断奶前(21d)表达量变化不明显,断奶后有显著下降(P<0.05)。④胃与结肠部位FcRn的表达比较稳定,一直保持在较低水平。【结论】仔猪不同组织中FcRn在十二指肠后段和空肠前段的表达水平最高,提示仔猪十二指肠、空肠是FcRn转运初乳中IgG的主要部位。仔猪肠道FcRn的表达量变化与初乳及乳汁中IgG含量的变化规律基本一致,证明了FcRn在肠道转运IgG中发挥重要作用。

[OBJECTIVE] To study the expression and the changes of neonatal Fc receptor （FcRn） in the gastroinstestinal （GI） tract of piglets from birth to post-weaning. [METHOD] Tissues were collected from Landrace- Large White crossbred piglets at 12 age points. RT-PCR detection was performed for FcRn mRNA expression and was relatively quantitated. [RESULTS] ①FcRn mRNA was detected as positive in all the GI tissues, among which the strongest signals existed at duodenum and jejunum, whereas the weakest at colon and stomach.②High level of FcRn gene transcription was detected in duodenum and jejunum from piglets at birth and remained high within 4 days of age, but significantly decressed since 7-day age, reaching the lowest at weaning （21d）. ③At ileum, FcRn expression was relatively low and the amount did not change much until post weaning. ④The expression of FcRn at colon and stomach was constant at a low level. [CONCLUSION] FcRn was most significantly expressed at duodenum and jejunum in piglets, indicating that duodenum and jejunum are the main sites of IgG transport from the colostrum. The role of FcRn transcytosis was verified by the fact that insteninal FcRn expression correlates with the IgG level in the colostrum and milk.