Reactive oxygen species-quenching and anti-apoptotic effect of polaprezinc on indomethacin-induced small intestinal epithelial cell injury.
BACKGROUND
To protect the small intestine from mucosal injury induced by nonsteroidal anti-inflammatory drugs is one of the critical issues in the field of gastroenterology. Polaprezinc (PZ), a gastric muco-protecting agent, has been widely used for the treatment of gastric ulcer and gastritis for its unique effects, such as its strong reactive oxygen species (ROS)-quenching effect. The aim of this study was to clarify the mechanism by which indomethacin-induced small intestinal mucosal injury occurs, by using a rat intestinal epithelial cell line (RIE-1). In addition, the protective role of PZ and the possible mechanism of its effect on indomethacin-induced small intestinal injury were investigated.


METHODS
Cell death was evaluated by methyl thiazolyl tetrazolium (MTT) assay and a double-staining method with Hoechst33342 dye and propidium iodide. Indomethacin-induced ROS production was evaluated by detecting the oxidation of a redox-sensitive fluorogenic probe, RedoxSensor, and the oxidation of cysteine residues of proteins (protein S oxidation). The activation of cytochrome c, smac/DIABLO, and caspase-3 was assessed by western blotting. In some experiments, PZ or its components, L: -carnosine and zinc, were used.


RESULTS
We found that indomethacin caused apoptosis in RIE-1 cells in a dose- and time-dependent manner. Indomethacin also induced ROS production and an increase in the protein S oxidation of RIE-1. Pretreatment of RIE-1 with PZ or zinc sulfate, but not L: -carnosine, significantly reduced the indomethacin-induced apoptosis. PZ prevented ROS production and the increase in protein S-oxidation. PZ inhibited indomethacin-induced cytochrome c and smac/DIABLO release and subsequent caspase-3 activation.


CONCLUSIONS
The protective effect of PZ on indomethacin-induced small intestinal injury may be dependent on its ROS-quenching effect.
Omatsu
Tatsushi
T
Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan.
Naito
Yuji
Y
Handa
Osamu
O
Mizushima
Katsura
K
Hayashi
Natsuko
N
Qin
Ying
Y
Harusato
Akihito
A
Hirata
Ikuhiro
I
Kishimoto
Etsuko
E
Okada
Hitomi
H
Uchiyama
Kazuhiko
K
Ishikawa
Takeshi
T
Takagi
Tomohisa
T
Yagi
Nobuaki
N
Kokura
Satoshi
S
Ichikawa
Hiroshi
H
Yoshikawa
Toshikazu
T
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000633:toxicity; D000897:Anti-Ulcer Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002336:Carnosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002460:Cell Line; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D007213:Indomethacin / Q000633:toxicity*; D007413:Intestinal Mucosa / Q000187:drug effects / Q000473:pathology; D009942:Organometallic Compounds / Q000494:pharmacology*; D010084:Oxidation-Reduction / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects; D017293:Protein S / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D017967:Zinc Compounds / Q000494:pharmacology
D000894:Anti-Inflammatory Agents, Non-Steroidal; D000897:Anti-Ulcer Agents; D009942:Organometallic Compounds; D017293:Protein S; D017382:Reactive Oxygen Species; D017967:Zinc Compounds; C061957:polaprezinc; D002336:Carnosine; D007213:Indomethacin