Role of caspase-3 and nitric oxide synthase-2 in gastric mucosal injury induced by indomethacin: effect of sucralfate.
BACKGROUND
Apoptosis is the process of programmed cell death characterized by a series of distinct biochemical and morphological changes which involve activation of caspase proteases cascade that remains under the regulatory control of nitric oxide. Here, we investigated the activity of a key apoptotic protease, caspase-3, and the expression of inducible nitric oxide synthase (NOS-2) and tumor necrosis factor-alpha (TNF-alpha) associated with gastric epithelial cells apoptosis during indomethacin-induced gastric mucosal injury, and evaluated the effect of antiulcer agent sucralfate on this process.


METHODS
The experiments were conducted with groups of rats pretreated intragastrically with 200 mg/kg sucralfate or the vehicle, followed 30 min later by an intragastric dose of indomethacin at 60 mg/kg. The animals were killed 2 h later and their gastric mucosal tissue used for macroscopic assessment, assays of epithelial cells apoptosis and TNF-alpha, and the measurements of caspase-3 and NOS-2 activities.


RESULTS
In the absence of sucralfate, indomethacin caused multiple hemorrhagic lesions occupying 29.3 mm2 of the corpus area, and accompanied by a 20-fold enhancement in gastric epithelial cells apoptosis and a 47% increase in mucosal expression of TNF-alpha, while NOS-2 showed an 11.9-fold induction and the activity of caspase-3 increased 3.9-fold. Pretreatment with sucralfate produced a 59.7% reduction in the extent of mucosal damage caused by indomethacin, a 41.2% decrease in the epithelial cells apoptosis and a 33.4% reduction in TNF-alpha, while the activity of caspase-3 decreased by 45% and that of NOS-2 showed a 44.7% decline.


CONCLUSIONS
The results implicate caspase-3 in the process of indomethacin-induced gastric epithelial cells apoptosis, and point towards participation of NOS-2 in the amplification of the cell death signaling cascade. Our findings also show that sucralfate protection against gastric mucosal injury caused by indomethacin involves the suppression of NOS-2 and the apoptotic events propagated by caspase-3.
Slomiany
B L
BL
Research Center, University of Medicine and Dentistry of New Jersey, Newark, USA.
Piotrowski
J
J
Slomiany
A
A
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism / Q000502:physiology*; D005753:Gastric Mucosa / Q000187:drug effects / Q000201:enzymology* / Q000293:injuries*; D007213:Indomethacin / Q000378:metabolism / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000378:metabolism / Q000502:physiology*; D052247:Nitric Oxide Synthase Type II; D051381:Rats; D017207:Rats, Sprague-Dawley; D013392:Sucralfate / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D014409:Tumor Necrosis Factor-alpha; D013392:Sucralfate; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; D007213:Indomethacin