Objective and design: To investigate the role of non-protein sulfhydryl groups (NP-SH) and leukocyte adhesion in the protective effect of lipopolysaccharide (LPS) from Escherichia coli against indomethacin-induced gastropathy.
Materials or subjects: Male Wistar rats were divided into four groups: saline, LPS, saline + indomethacin and LPS + indomethacin, with six rats in each group.
Treatment: Rats were pretreated with LPS (300 microg/kg, by intravenous) or saline. After 6 h, indomethacin was administered (20 mg/kg, by gavage).
Methods: Three hours after treatments, rats were killed. Macroscopic gastric damage, gastric NP-SH concentration, myeloperoxidase (MPO) activity and mesenteric leukocyte adhesion (intravital microscopy) were assessed. Statistical analysis was performed using one-way analysis of variance followed by the Newman-Keuls test. Statistical significance was set at P < 0.05.
Results: LPS reduced the gastric damage, gastric MPO activity and increased gastric NP-SH concentration in indomethacin-induced gastropathy. LPS alone increased gastric NP-SH when compared to saline. Indomethacin increased leukocyte adhesion when compared to the saline, and LPS reduced indomethacin-induced leukocyte adhesion. In addition, LPS alone did not change leukocyte adhesion, when compared to the saline.
Conclusion: LPS protective effect against indomethacin-induced gastropathy is mediated by an increase in the NP-SH and a decrease in leukocyte-endothelial adhesion.