Oral administration of propionic acid during lactation enhances the colonic barrier function.
BACKGROUND
Propionic acid is a three-carbon short chain fatty acid (SCFA) that has various effects on colonic functions. Although several studies have shown the effects of propionic acid on intestinal mucosal barrier function, studies of the promotion effect during pre-weaning are rare in the literature as far as we know.


METHODS
Pre-weaning male Sprague-Dawley rats 7 days after birth were given an oral 0.2 mL/10 g of 200 mM propionic acid solution in the propionic acid group or normal saline solution in the control group by gavage twice a day for ten days. The proximal colonic contents were used for extraction and determination of propionic acid by gas chromatographic analysis; the transepithelial electrical resistance (TER) of colonic tissue was detected by an Ussing chamber; the alterations of ZO-1, Claudin-1, Claudin-8 and Occludin proteins were analyzed by Western blot and immunohistochemistry; and The activity of ERK and p38 MAPK was determined by the phosphorylation status of ERK1/2 and p38 with Western blot.


RESULTS
Our results suggested a higher concentration (23.5 ± 1.9 mmol/kg) of propionic acid compared to the physiological concentration (18.1 ± 0.9 mmol/kg) in colonic contents after oral administration increased the value of TER and the expression of ZO-1, Claudin-1, Claudin-8 and Occludin compared to the control group. Furthermore, the expression levels of phosphorylated ERK1/2 and p38 MAPK were increased in propionic acid group.


CONCLUSIONS
We concluded that continuous oral administration of propionic acid during lactation may increase its concentration in the proximal colon and promote epithelial barrier function of proximal colon by enhancing the expression of ZO-1, Claudin-8, Claudin-1 and Occludin via increases in the expression of ERK1/2 and p38 MAPK.
Department of Pediatric Surgery, the Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University, Xueyuan West Road, 109#, Wenzhou, Zhejiang, 325000, China.
Zhaobo
http://orcid.org/0000-0002-3933-4505
Z
Xia
Department of Pediatric Surgery, the Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University, Xueyuan West Road, 109#, Wenzhou, Zhejiang, 325000, China.
Yijiang
Y
Han
Department of Pediatric Surgery, the Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University, Xueyuan West Road, 109#, Wenzhou, Zhejiang, 325000, China.
Ke
K
Wang
Department of Pediatric Surgery, the Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University, Xueyuan West Road, 109#, Wenzhou, Zhejiang, 325000, China.
Shikun
S
Guo
Department of Pediatric Surgery, the First Affiliated Hospital of Wenzhou Medical University, Baixiang South, Wenzhou, Zhejiang, 325000, China.
Dazhou
D
Wu
Department of Pediatric Surgery, the Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University, Xueyuan West Road, 109#, Wenzhou, Zhejiang, 325000, China.
Xiaozhong
X
Huang
Department of Pediatric Surgery, the Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University, Xueyuan West Road, 109#, Wenzhou, Zhejiang, 325000, China. wmclzr@163.com.
Zhongrong
Z
Li
Department of Pediatric Surgery, the Second Affiliated Hospital & Yuying Children's Hospital of Wenzhou Medical University, Xueyuan West Road, 109#, Wenzhou, Zhejiang, 325000, China. wz.zhulibin@aliyun.com.
Libin
L
Zhu
D000284:Administration, Oral; D000818:Animals; D062445:Claudin-1 / Q000378:metabolism; D057167:Claudins / Q000378:metabolism; D003106:Colon / Q000187:drug effects / Q000378:metabolism*; D004353:Drug Evaluation, Preclinical; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism; D020935:MAP Kinase Signaling System; D008297:Male; D062793:Occludin / Q000378:metabolism; D010539:Permeability; D010766:Phosphorylation; D011422:Propionates / Q000008:administration & dosage* / Q000493:pharmacokinetics; D011499:Protein Processing, Post-Translational; D017207:Rats, Sprague-Dawley; D019108:Tight Junctions / Q000378:metabolism; D014018:Tissue Distribution; D062826:Zonula Occludens-1 Protein / Q000378:metabolism
D062445:Claudin-1; D057167:Claudins; C568114:Cldn1 protein, rat; D062793:Occludin; C568987:Ocln protein, rat; D011422:Propionates; C569044:Tjp1 protein, rat; D062826:Zonula Occludens-1 Protein; C502011:claudin 8; C029658:propionic acid
Barrier function; Gas chromatography; Propionic acid; Tight junction; Ussing chamber