Gastric adaptation to aspirin (ASA) is associated with increased expression of heat shock protein (HSP 70) and decreased apoptosis due to downregulation of bax

Abstract

The monolayers were incubated with or without NO-donor sodium nitroprusside (SNP, 300/LM). The potential role of cGMP as a second messenger of NO was investigated using 8-Br-cGMP. In order to assess whether the effects of NO are mediated by its reaction with superoxide (02 ) , yielding peroxynitrite (ONOO·)3, we studied the effects of O£' source s diethylthiocarbamate (DOC, superoxide dismutase inhibitor) and pyrogallol (PG, an O2'' generator) with or without SNP. We further studied the effects of O2'' scavengers allopurinol (AP, an inhibitor of xantine oxidase), and superoxide dismutase (SOD, catalyzes O2'to H20 2) together with catalase (C, eliminates H20 2) with or without of SNP. Results. Retardation of wound healing caused by SNP was enhanced by DDC and PG, and ameliorated by O2'' scavengers AP and SOD+C (Table I) . 8-Br-cGMP had no significant effect on wound restitution (cell migration (/Lml24 h) 546:= 16 vs. 440:=68 , and apoptosis index % 8.2:!:3.4 vs. 9.4:!:2.4 in cGMP and controls , respectively). Conclusions. SNP retards gastric restitution by inhibiting cell migration and inducing cellular apoptosis . These effects are not mediated by cGMP, but (ONOO')3 or its derivatives may contribute to this process .