Stimulation of cytosolic and mitochondrial calcium mobilization by indomethacin in Caco-2 cells: modulation by the polyphenols quercetin, resveratrol and rutin.

BACKGROUND

The effect of indomethacin (INDO) on Ca(2+) mobilization, cytotoxicity, apoptosis and caspase activation and the potential protective effect of quercetin (QUE), resveratrol (RES) and rutin (RUT) were determined in Caco-2 cells.

METHODS

Caco-2 cells were incubated with INDO in the presence or absence of QUE, RES or RUT. The concentrations of Ca(2+) in the cytosol (Fluo-3 AM) and mitochondria (Rhod-2 AM) were determined as well as the cytotoxicity (MTT reduction and LDH leakage), apoptosis (TUNEL) and caspase-3 and 9 activities.

RESULTS

INDO promoted Ca(2+) efflux from the endoplasmic reticulum (ER), resulting in an early, but transient, increment of cytosolic Ca(2+) at 3.5min, followed by a subsequent increment of intra-mitochondrial Ca(2+) at 24min. INDO also induced cytotoxicity, apoptosis, and increased caspase activities and cytochrome c release. All these alterations were prevented by the inhibitors of the IP3R and RyR receptors, 2-Aminoethoxydiphenyl borate (2-APB) and dantrolene. QUE was the most efficient polyphenol in preventing Ca(2+) mobilization induced by INDO and all of its consequences including cytotoxicity and apoptosis.

CONCLUSIONS

In Caco-2 cells, INDO stimulates ER Ca(2+) mobilization, probably through the activation of IP3R and RyR receptors, and the subsequent entry of Ca(2+) into the mitochondria. Polyphenols protected the cells against the Ca(2+) mobilization induced by INDO and its consequences on cytotoxicity and apoptosis.

GENERAL SIGNIFICANCE

These results confirm the possibility of using polyphenols and particularly QUE for the protection of the gastroduodenal mucosa in subjects consuming NSAIDs.