Ellagic acid protects against arsenic trioxide-induced cardiotoxicity in rat.

Arsenic trioxide (As2O3) is utilized for treating patients suffering from hematological malignancies particularly acute promyelocytic leukemia. Unfortunately, the extensive application of this chemotherapeutic agent has been limited due to its adverse effects such as cardiotoxicity. Ellagic acid, as a phenolic compound, has shown to exert antioxidant, anti-inflammatory, antifibrotic, and antiatherogenic properties. It is also capable of protecting against drug toxicity. In this study, we evaluated whether ellagic acid can protect against As2O3-induced heart injury in rats. Thirty-two male Wistar rats were randomly divided into four treatment groups, that is, control (0.2 mL of normal saline, intraperitoneally (ip)), As2O3 (5 mg/kg, ip), As2O3 plus ellagic acid, and ellagic acid (30 mg/kg, orally) groups. The drugs were administered daily for 10 days and pretreatment with ellagic acid was performed 1 h prior to As2O3 injection. Cardiotoxicity was characterized by electrocardiological, biochemical, and histopathological evaluations. Our results showed that ellagic acid pretreatment significantly ameliorated As2O3-induced increase in glutathione peroxidase activity and malondialdehyde concentration ( p < 0.05 and p < 0.001, respectively) and also diminished QTc prolongation ( p < 0.0001) and cardiac tissue damages. Pretreatment with ellagic acid also lowered the increased troponin I ( p < 0.0001) and creatine kinase isoenzyme MB ( p < 0.01) levels in response to As2O3. In conclusion, results of this study demonstrated that ellagic acid has beneficial cardioprotective effects against As2O3 toxicity. It is suggested that the protective effects were mediated by antioxidant properties of ellagic acid.

Angiotensin II induces NF-κB, JNK and p38 MAPK activation in monocytic cells and increases matrix metalloproteinase-9 expression in a PKC- andRho kinase-dependent manner

Angiotensin II (ANG II), the main effector of the renin-angiotensin system, is implicated in endothelial permeability, recruitment and activation of the immune cells, and also vascular remodeling through induction of inflammatory genes. Matrix metalloproteinases (MMPs) are considered to be important inflammatory factors. Elucidation of ANG II signaling pathways and of possible cross-talks between their components is essential for the development of efficient inhibitory medications. The current study investigates the inflammatory signaling pathways activated by ANG II in cultures of human monocytic U-937 cells, and the effects of specific pharmacological inhibitors of signaling intermediates on MMP-9 gene (MMP-9) expression and activity. MMP-9 expression was determined by real-time PCR and supernatants were analyzed for MMP-9 activity by ELISA and zymography methods. A multi-target ELISA kit was employed to evaluate IκB, NF-κB, JNK, p38, and STAT3 activation following treatments. Stimulation with ANG II (100 nM) significantly increased MMP-9 expression and activity, and also activated NF-κB, JNK, and p38 by 3.8-, 2.8- and 2.2-fold, respectively (P < 0.01). ANG II-induced MMP-9 expression was significantly reduced by 75 and 67 percent, respectively, by co-incubation of the cells with a selective inhibitor of protein kinase C (GF109203X, 5 µM) or of rho kinase (Y-27632, 15 µM), but not with inhibitors of phosphoinositide 3-kinase (wortmannin, 200 nM), tyrosine kinases (genistein, 100 µM) or of reactive oxygen species (α-tocopherol, 100 µM). Thus, protein kinase C and Rho kinase are important components of the inflammatory signaling pathways activated by ANG II to increase MMP-9 expression in monocytic cells. Both signaling molecules may constitute potential targets for effective management of inflammation.

Angiotensin II induces NF-κB, JNK and p38 MAPK activation in monocytic cells and increases matrix metalloproteinase-9 expression in a PKC- andRho kinase-dependent manner.

Angiotensin II (ANG II), the main effector of the renin-angiotensin system, is implicated in endothelial permeability, recruitment and activation of the immune cells, and also vascular remodeling through induction of inflammatory genes. Matrix metalloproteinases (MMPs) are considered to be important inflammatory factors. Elucidation of ANG II signaling pathways and of possible cross-talks between their components is essential for the development of efficient inhibitory medications. The current study investigates the inflammatory signaling pathways activated by ANG II in cultures of human monocytic U-937 cells, and the effects of specific pharmacological inhibitors of signaling intermediates on MMP-9 gene (MMP-9) expression and activity. MMP-9 expression was determined by real-time PCR and supernatants were analyzed for MMP-9 activity by ELISA and zymography methods. A multi-target ELISA kit was employed to evaluate IκB, NF-κB, JNK, p38, and STAT3 activation following treatments. Stimulation with ANG II (100 nM) significantly increased MMP-9 expression and activity, and also activated NF-κB, JNK, and p38 by 3.8-, 2.8- and 2.2-fold, respectively (P < 0.01). ANG II-induced MMP-9 expression was significantly reduced by 75 and 67%, respectively, by co-incubation of the cells with a selective inhibitor of protein kinase C (GF109203X, 5 µM) or of rho kinase (Y-27632, 15 µM), but not with inhibitors of phosphoinositide 3-kinase (wortmannin, 200 nM), tyrosine kinases (genistein, 100 µM) or of reactive oxygen species (α-tocopherol, 100 µM). Thus, protein kinase C and Rho kinase are important components of the inflammatory signaling pathways activated by ANG II to increase MMP-9 expression in monocytic cells. Both signaling molecules may constitute potential targets for effective management of inflammation.