Effects of indomethacin on erythrocyte nitric oxide metabolism and erythrocyte deformability

Increased erythrocyte filtration index (decreased erythrocyte deformability; ED) was observed in patients with Behçet disease. When patients with Behçet took indomethacin, decreased values of erythrocyte acetylcholinesterase enzyme activity were obtained. An inverse association between nitric oxide (NO) efflux from erythrocytes and ED values was verified in blood samples of patients with vascular inflammatory diseases. The aim of this in vitro study was to verify the effect of indomethacin on ED, NO efflux, nitrite nitrate, peroxynitrite and nitroso- glutathione (GSNO) in the presence of protein tyrosine kinase (PTK Syk), protein tyrosine phosphatase (PTP), adenylyl cyclase (AC) and phosphatidylinositol 3 kinase (PI3K) enzyme inhibitors respectively Syk inhibitor, calpeptin, MDL and wortmannin (WORT). Blood samples from ten healthy donors were divided and aliquots were performed in absence (control aliquot) and presence of indomethacin or indomethacin plus each one of the inhibitors. Further ED and NO efflux and its metabolites were evaluated by the usual methodology. A significant increase in ED values was noted in the presence of indomethacin plus WORT. No significant differences where verified in NO efflux from erythrocytes in all blood aliquots. Significantly increase in GSNO concentration in the presence of indomethacin plus calpeptin, MDL or Wort were observed. Nitrate and peroxynitrite concentrations increased or decreased significantly respectively in all aliquots in relation to the control one. The nitrite levels increased in the aliquots with indomethacin and indomethacin plus MDL, or indomethacin plus Syk. In conclusion indomethacin act as antioxidant decreasing peroxynitrite, not changing NO efflux values and increasing nitrate levels independent of band 3 phosphorylation degree or cyclic adenosine monophosphate (cAMP) concentration. Indomethacin mobilizes nitrite and GSNO in dependant of band 3 phosphorylation degree and cAMP. Indomethacin did not change erythrocyte deformability, unless in combination with wortmannin which increased it.