title: Protection of rat intestinal epithelial cells from ischemia/reperfusion injury by (D-Ala2, D-Leu5)-enkephalin through inhibition of the MKK7-JNK signaling pathway.
abstract: Previous studies have demonstrated that (D‑Ala2, D‑Leu5)‑enkephalin (DADLE) protects rats from hepatic ischemia/reperfusion (I/R) injury. In the present study, DADLE was also observed to alleviate IR‑induced intestinal epithelial cell injury in rats by inhibiting mitogen‑activated protein kinase kinase 7 (MKK7)‑c‑Jun N‑terminal kinase (JNK) pathway signaling. To investigate the protective effect of DADLE on hypoxia/reoxygenation injury in rat intestinal epithelial cells, rat intestinal epithelial cells were treated with different concentrations of DADLE, following which the cell survival rate was determined using a tetrazolium (MTT) colorimetric assay, and apoptosis was determined using flow cytometry. To confirm whether the protective effect of DADLE was due to its effect on MKK7‑JNK signaling, the phosphorylation levels of MKK7 and JNK were analyzed using western blot analysis following treatment with different concentrations of DADLE. The results demonstrated that, following treatment with DADLE, the survival rate of the rat intestinal cells subjected to I/R‑induced injury increased significantly and the apoptotic rate decreased in a concentration‑dependent manner. In addition, the levels of phosphorylated MKK7 and JNK decreased in a concentration‑dependent manner following treatment with DADLE. Silencing the gene expression of MKK7 using small interfering RNA prior to DADLE treatment resulted in a reduction in the protective effects of DADLE on the rat intestinal epithelial cells subjected to I/R injury. Collectively, the results of the present study demonstrated that the protective effects of DADLE in I/R injury in rat intestinal cells occurred through inhibition of the MKK7‑JNK pathway.
authors.affiliation: Department of Gastrointestinal Surgery, Guilin Medical University, Affiliated Hospital, Guilin, Guangxi 541001, P.R. China.
authors.forename: Zhenran
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Hepatobiliary Surgery, Guilin Medical University, Affiliated Hospital, Guilin, Guangxi 541001, P.R. China.
authors.forename: Bo
authors.initials: B
authors.lastname: Tang
authors.affiliation: Department of Pathology, Guilin Medical University, Affiliated Hospital, Guilin, Guangxi 541001, P.R. China.
authors.forename: Fang
authors.initials: F
authors.lastname: Tang
authors.affiliation: Department of Hepatobiliary Surgery, Guilin Medical University, Affiliated Hospital, Guilin, Guangxi 541001, P.R. China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Gastrointestinal Surgery, Guilin Medical University, Affiliated Hospital, Guilin, Guangxi 541001, P.R. China.
authors.forename: Guangyu
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Department of Gastrointestinal Surgery, Guilin Medical University, Affiliated Hospital, Guilin, Guangxi 541001, P.R. China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhong
authors.affiliation: Department of Gastrointestinal Surgery, Guilin Medical University, Affiliated Hospital, Guilin, Guangxi 541001, P.R. China.
authors.forename: Chencheng
authors.initials: C
authors.lastname: Dong
authors.affiliation: Department of Hepatobiliary Surgery, Guilin Medical University, Affiliated Hospital, Guilin, Guangxi 541001, P.R. China.
authors.forename: Songqing
authors.initials: S
authors.lastname: He
mesh_terms: D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D002460:Cell Line; D049109:Cell Proliferation; D002470:Cell Survival / Q000187:drug effects; D004195:Disease Models, Animal; D016308:Enkephalin, Leucine-2-Alanine / Q000494:pharmacology*; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005260:Female; D059585:G1 Phase Cell Cycle Checkpoints / Q000187:drug effects; D007422:Intestines / Q000166:cytology; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D048688:MAP Kinase Kinase 7 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D008297:Male; D018696:Neuroprotective Agents / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000378:metabolism / Q000473:pathology
chemical_list: D051017:Apoptosis Regulatory Proteins; D018696:Neuroprotective Agents; D034741:RNA, Small Interfering; D016308:Enkephalin, Leucine-2-Alanine; D048031:JNK Mitogen-Activated Protein Kinases; D048688:MAP Kinase Kinase 7