Modulation of Doxorubicin-Induced Cardiac Dysfunction in Toll-Like Receptor-2–Knockout Mice

Abstract
Background— Toll-like receptors (TLRs) are members of the interleukin-1 receptor family and are involved in the responsiveness to pathogen-associated molecular patterns. Recent studies have demonstrated that TLRs are activated by endogenous signals, such as heat shock proteins and oxidative stress, which may contribute to congestive heart failure. Oxidative stress is one of the major factors in doxorubicin (Dox)-induced cardiac dysfunction. Thus, we hypothesized that TLRs contribute to the pathogenesis of Dox-induced cardiac dysfunction. Methods and Results— Cardiac dysfunction was induced by a single injection of Dox (20 mg/kg IP) into wild-type (WT) mice and TLR-2–knockout (KO) mice. Five days after Dox injection, left ventricular dimension at end-diastole was smaller and fractional shortening was higher in KO mice compared with WT mice ( P P P P Conclusions— These findings suggest that TLR-2 may play a role in the regulation of inflammatory and apoptotic mediators in the heart after Dox administration.