The blockade of cyclooxygenases-1 and -2 reduces the effects of hypoxia on endothelial cells.
Hypoxia activates endothelial cells by the action of reactive oxygen species generated in part by cyclooxygenases (COX) production enhancing leukocyte transmigration. We investigated the effect of specific COX inhibition on the function of endothelial cells exposed to hypoxia. Mouse immortalized endothelial cells were subjected to 30 min of oxygen deprivation by gas exchange. Acridine orange/ethidium bromide dyes and lactate dehydrogenase activity were used to monitor cell viability. The mRNA of COX-1 and -2 was amplified and semi-quantified before and after hypoxia in cells treated or not with indomethacin, a non-selective COX inhibitor. Expression of RANTES (regulated upon activation, normal T cell expressed and secreted) protein and the protective role of heme oxygenase-1 (HO-1) were also investigated by PCR. Gas exchange decreased partial oxygen pressure (PaO2) by 45.12 +/- 5.85% (from 162 +/- 10 to 73 +/- 7.4 mmHg). Thirty minutes of hypoxia decreased cell viability and enhanced lactate dehydrogenase levels compared to control (73.1 +/- 2.7 vs 91.2 +/- 0.9%, P < 0.02; 35.96 +/- 11.64 vs 22.19 +/- 9.65%, P = 0.002, respectively). COX-2 and HO-1 mRNA were up-regulated after hypoxia. Indomethacin (300 microM) decreased COX-2, HO-1, hypoxia-inducible factor-1alpha and RANTES mRNA and increased cell viability after hypoxia. We conclude that blockade of COX up-regulation can ameliorate endothelial injury, resulting in reduced production of chemokines.
Gloria
M A
MA
Laboratório de Imunologia Clínica e Experimental, Divisão de Nefrologia, Universidade Federal de São Paulo, Hospital do Rim e Hipertensão, Fundação Oswaldo Ramos, São Paulo, SP, Brasil.
Cenedeze
M A
MA
Pacheco-Silva
A
A
Câmara
N O S
NO
D000818:Animals; D015687:Cell Hypoxia / Q000187:drug effects*; D002470:Cell Survival / Q000502:physiology; D051545:Cyclooxygenase 1 / Q000235:genetics / Q000378:metabolism*; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D042783:Endothelial Cells / Q000378:metabolism* / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic; D051547:Heme Oxygenase-1 / Q000378:metabolism; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D007213:Indomethacin / Q000494:pharmacology*; D051379:Mice; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger; D015398:Signal Transduction
D016861:Cyclooxygenase Inhibitors; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D012333:RNA, Messenger; D051547:Heme Oxygenase-1; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D007213:Indomethacin