Anti-inflammatory agents and monoHER protect against DOX-induced cardiotoxicity and accumulation of CML in mice

Abstract

Cardiac damage is the major limiting factor for the clinical use of doxorubicin (DOX). Preclinical studies indicate that inflammatory effects may be involved in DOX-induced cardiotoxicity. Nepsilon-(carboxymethyl) lysine (CML) is suggested to be generated subsequent to oxidative stress, including inflammation. Therefore, the aim of this study was to investigate whether CML increased in the heart after DOX and whether anti-inflammatory agents reduced this effect in addition to their possible protection on DOX-induced cardiotoxicity. These effects were compared with those of the potential cardioprotector 7-monohydroxyethylrutoside (monoHER).BALB/c mice were treated with saline, DOX alone or DOX preceded by ketoprofen (KP), dexamethasone (DEX) or monoHER. Cardiac damage was evaluated according to Billingham. Nepsilon-(carboxymethyl) lysine was quantified immunohistochemically. Compared to saline, a 21.6-fold increase of damaged cardiomyocytes was observed in mice treated with DOX (P<0.001). Addition of KP, DEX or monoHER before DOX significantly reduced the mean ratio of abnormal cardiomyocytes in comparison to mice treated with DOX alone (P<or=0.02). In addition, DOX induced a significant increase in the number of CML-stained intramyocardial vessels per mm2 (P=0.001) and also in the intensity of CML staining (P=0.001) compared with the saline-treated group. Nepsilon-(carboxymethyl) lysine positivity was significantly reduced (P<or=0.01) by DOX-DEX, DOX-KP and DOX-monoHER. These results confirm that inflammation plays a role in DOX-induced cardiotoxicity, which is strengthened by the observed DOX-induced accumulation of CML, which can be reduced by anti-inflammatory agents and monoHER.

Figure 1

Immunohistochemical detection of CML in the mouse (× 63). Arrow: CML deposition on endothelial cells in intramyocardial blood vessel. (A) immunohistochemical detection of CML in the heart tissue of a mouse after DOX treatment alone, whereas (B) is an image without addition of the primary antibody.

Figure 2

The mean number of vessels per mm² weakly, moderately and strongly positive after staining for CML in intramyocardial vessels in the heart tissue of treated mice. A significant difference (P=0.001) was found between the mice treated with DOX alone and the animals treated with saline when the mean number of moderately plus strongly stained vessels per mm² were considered (^* no significant difference in the mean number of strongly plus moderately stained CML vessels per mm² in comparison to the saline-treated group and P⩽0.01 when compared with the DOX-treated group).