Upregulation of Beta 1 and Arachidonic Acid Metabolizing Enzymes in the Mouse Hearts and Kidneys after Sub Chronic Administration of Rofecoxib.

Background: An imbalance in the levels of arachidonic acid (ARA) metabolites in cardiovascular disorders and drug-induced cardiotoxicity have been previously described.
Aims: This study aimed to investigate the influence of cyclooxygenase-2 (COX-2) selective inhibitors on the gene expression of ARA-metabolizing genes and beta1 gene in the hearts and kidneys of experimental mice.
Methods: Thirty-five balb/c mice were divided into five groups with seven mice per group. The groups were then given two distinct types of COX-2 selective inhibitors, rofecoxib and celecoxib, in two different doses equivalent to those used in human treatment for 30 days. The mRNA expression of beta1, ace2, and ARA-metabolizing genes, coxs, lipoxygenases (aloxs), and cytochrome p450 (cyp450s) in mice heart and kidneys were assessed. Genes were analyzed using real-time polymerase chain reaction analysis. In addition, rofecoxib-induced histological alterations were examined.
Results: It was found that only the high dose of rofecoxib (5 mg/kg) caused toxicological alterations, a finding that was indicated by a significant increase (P < 0.05) in the relative weight of the mouse hearts and increase in the ventricle wall thickness as observed through pathohistological examination. This increase was associated with a significant increase in the mRNA expression level of the beta1 receptor in both the heart and kidneys of the mice (53- and 12-fold, respectively). The expression of both cox1 and 2 genes was increased 4-fold in the kidneys. In addition, the expression of the alox12 gene increased significantly (by 67-fold in the heart and by 21-fold in the kidney), while alox15 gene expression was upregulated in the heart by 8-fold and 5-fold in the kidney. The genes responsible for synthesizing 20- Hydroxyeicosatetraenoic acid (cyp4a12 and cyp1a1) were significantly upregulated (P < 0.05) in the hearts of high-dose rofecoxib-treated mice by 7- and 17 -fold, respectively. In addition, the expression of epoxyeicosatrienoic acid-synthesizing genes, cyp2c29 and cyp2j5, was increased significantly (P < 0.05) in the hearts of high-dose rofecoxib-treated mice by 4- and 16-fold, respectively.
Conclusion: Rofecoxib caused upregulation of the mRNA expression of the beta 1 gene in association with increased expression of ARA-metabolizing genes in mouse hearts and kidneys. These findings may help us understand the molecular cardiotoxic mechanism of rofecoxib.
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