Doxorubicin Induces Necroptosis in Young Mice

Abstract

Despite its potency as a chemotherapeutic drug, the prevalence of cardiotoxicity resulting from doxorubicin treatment in childhood survivors of cancer is a major concern. While the occurrence of apoptosis has been well ascertained in doxorubicin induced cardiotoxicity (DIC) by several studies; however, the presence of necroptosis in young DIC remains unknown. We hypothesize that doxorubicin will induce necroptotic cell death and adverse cardiac remodeling in young mice. Therefore, in this study we investigated the possible occurrence of necroptotic cell death in DIC in young mice in‐vivo to delineate underlying pathological mechanism.C57BL6 mice (6 + 2 weeks of age) were divided into two groups: Control (mice were given 0.9% saline) and Dox (drug was administered at 2.5mg/kg body weight (BW) for six i.p injection, with a cumulative dose of 15mg/kg BW). At day 14, heart function was examined using echocardiography, mice were euthanized. Heart tissues were collected and analyzed for necroptosis, adverse cardiac remodeling using immunohistochemistry, and histology. Upon analysis, we observed that Dox treatment significantly (p<0.05) increased the expression of necroptotic markers [Receptor interacting Serine/Threonine kinase 1 and 3 (RIPK1, RIPK3) and Mixed Lineage kinase domain‐Like (MLKL)] as confirmed by immunohistochemistry. Furthermore, histological analysis showed adverse cardiac remodeling with significant increase (p<0.05) in cardiac hypertrophy and fibrosis in Dox group compared to control. Moreover, a significant decrease (p<0.05) in heart function was observed in Dox treated animals compared to control. In conclusion the results of our study suggest that doxorubicin, induces necroptotic cell death which further leads to adverse cardiac remodeling in Dox treated young mice.