Department of Surgery, Massachusetts General Hospital, Boston, MA 02114, USA.
Gut. 2010 Nov;59(11):1476-84. doi: 10.1136/gut.2010.211706.
The intestinal microbiota plays a critical role in maintaining human health; however, the mechanisms governing the normal homeostatic number and composition of these microbes are largely unknown. Previously it was shown that intestinal alkaline phosphatase (IAP), a small intestinal brush border enzyme, functions as a gut mucosal defence factor limiting the translocation of gut bacteria to mesenteric lymph nodes. In this study the role of IAP in the preservation of the normal homeostasis of the gut microbiota was investigated.
Bacterial culture was performed in aerobic and anaerobic conditions to quantify the number of bacteria in the stools of wild-type (WT) and IAP knockout (IAP-KO) C57BL/6 mice. Terminal restriction fragment length polymorphism, phylogenetic analyses and quantitative real-time PCR of subphylum-specific bacterial 16S rRNA genes were used to determine the compositional profiles of microbiotas. Oral supplementation of calf IAP (cIAP) was used to determine its effects on the recovery of commensal gut microbiota after antibiotic treatment and also on the colonisation of pathogenic bacteria.
IAP-KO mice had dramatically fewer and also different types of aerobic and anaerobic microbes in their stools compared with WT mice. Oral supplementation of IAP favoured the growth of commensal bacteria, enhanced restoration of gut microbiota lost due to antibiotic treatment and inhibited the growth of a pathogenic bacterium (Salmonella typhimurium).
IAP is involved in the maintenance of normal gut microbial homeostasis and may have therapeutic potential against dysbiosis and pathogenic infections.
肠道微生物群在维持人体健康方面发挥着关键作用；然而，控制这些微生物正常稳态数量和组成的机制在很大程度上尚不清楚。先前的研究表明，肠道碱性磷酸酶（IAP）作为一种小肠刷状缘酶，是一种肠道黏膜防御因子，可限制肠道细菌向肠系膜淋巴结的易位。在这项研究中，研究了 IAP 在维持肠道微生物群正常稳态中的作用。
通过需氧和厌氧条件下的细菌培养，定量测定野生型（WT）和 IAP 敲除（IAP-KO）C57BL/6 小鼠粪便中的细菌数量。采用末端限制性片段长度多态性、系统发育分析和亚门特异性细菌 16S rRNA 基因的定量实时 PCR 来确定微生物群落的组成谱。口服补充牛 IAP（cIAP）用于确定其在抗生素治疗后恢复共生肠道微生物群以及定植致病性细菌方面的作用。
与 WT 小鼠相比，IAP-KO 小鼠的粪便中需氧菌和厌氧菌的数量明显减少，种类也不同。IAP 的口服补充有利于共生细菌的生长，增强了因抗生素治疗而丢失的肠道微生物群的恢复，并抑制了致病性细菌（鼠伤寒沙门氏菌）的生长。
IAP 参与维持正常肠道微生物群稳态，可能具有治疗肠道菌群失调和致病性感染的潜力。
