Rhein Alleviates Doxorubicin-Induced Myocardial Injury by Inhibiting the p38 MAPK/HSP90/c-Jun/c-Fos Pathway-Mediated Apoptosis

Doxorubicin (Dox) has been limited in clinical application due to its cardiac toxicity that varies with the dose. This study aimed to explore how Rhein modulates Dox-induced myocardial toxicity. The general condition and echocardiographic changes of mice were observed to evaluate cardiac function and structure, with myocardial cell injury and apoptosis checked by TUNEL and HE staining. The ELISA assessed markers of myocardial damage and inflammation. The TCMSP and SwissTargetPrediction databases were used to retrieve Rhein's targets while GeneCards was used to find genes related to Dox-induced myocardial injury. Intersection genes were analyzed by Protein–Protein Interaction Networks. The core network genes underwent GO and KEGG enrichment analysis using R software. Western blot was used to detect protein expression. Compared to the Dox group, there was no remarkable difference in heart mass /body mass ratio in the Rhein+Dox group. However, heart mass/tibia length increased. Mice in the Rhein+Dox group had significantly increased LVEF, LVPWs, and LVFS compared to those in the Dox group. Myocardial cell damage, inflammation, and apoptosis significantly reduced in the Rhein+Dox group compared to the model group. Eleven core network genes were selected. Further, Rhein+Dox group showed significantly downregulated expression of p38/p-p38, HSP90AA1, c-Jun/p-c-Jun, c-Fos/p-c-Fos, Bax, and cleaved-caspase-3/caspase-3 while Bcl-2 expression significantly upregulated compared to the Dox group. The study suggests that Rhein mediates cardioprotection against Dox-induced myocardial injury, at least partly, by influencing multiple core genes in the MAPK signaling pathway to inhibit myocardial cell apoptosis.