Involvement of reactive oxygen species in indomethacin-induced apoptosis of small intestinal epithelial cells.
BACKGROUND
The precise pathogenic mechanism of nonsteroidal antiinflammatory drug-induced small intestinal injury is still unknown. In the present study, we investigated the mechanism by which indomethacin induced mucosal injury by using an in vitro model of small intestine.


METHODS
The colon cancer cell line Caco-2, exhibiting a small intestinal phenotype starting as a crypt cell and differentiating to a villous phenotype, and RIE, a rat intestinal epithelial cell line, were employed. Indomethacin was added to differentiated the Caco-2 and RIE monolayer, and cell death was quantified by MTT assay and LDH release in the cell culture supernatant. Indomethacin-induced cell death was also qualified by fluorescent probes under the fluorescent microscope. As a functional study, the permeability of the Caco-2 monolayer was assessed by measuring transepithelial electrical resistance (TEER) and the flux of FITC-conjugated dextran across the monolayer. Indomethacin-induced reactive oxygen species production in Caco-2 and RIE was evaluated by redoxsensitive fluorogenic probes using a fluorometer. In some experiments, antioxidants were used to clarify the role of reactive oxygen species on indomethacin-induced Caco-2 cell death.


RESULTS
Indomethacin caused cell death (mainly apoptosis) of Caco-2 and RIE in a dose-and time-dependent manner that was correlated with increased permeability of the Caco-2 monolayer. Exposure of Caco-2 and RIE with indomethacin also resulted in a significant reactive oxygen species production that was inhibited by the pretreatment of these cells with antioxidants.


CONCLUSIONS
Taken together, reactive oxygen species production is one of the mechanisms by which indomethacin induced small intestinal injury.
Omatsu
Tatsushi
T
Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, 465 Kajiicho, Kamigyo-ku, Kyoto, 602-8566, Japan.
Naito
Yuji
Y
Handa
Osamu
O
Hayashi
Natsuko
N
Mizushima
Katsura
K
Qin
Ying
Y
Hirata
Ikuhiro
I
Adachi
Satoko
S
Okayama
Tetsuya
T
Kishimoto
Etsuko
E
Takagi
Tomohisa
T
Kokura
Satoshi
S
Ichikawa
Hiroshi
H
Yoshikawa
Toshikazu
T
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000633:toxicity*; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D018938:Caco-2 Cells; D002454:Cell Differentiation; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D017097:Electric Impedance; D005470:Fluorometry; D006801:Humans; D007213:Indomethacin / Q000008:administration & dosage / Q000633:toxicity*; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism; D010539:Permeability / Q000187:drug effects; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013997:Time Factors
D000894:Anti-Inflammatory Agents, Non-Steroidal; D000975:Antioxidants; D017382:Reactive Oxygen Species; D007213:Indomethacin