Guizhi Gancao Decoction protects against doxorubicin-induced cardiotoxicity by intervening in microtubule acetylation

ETHNOPHARMACOLOGICAL RELEVANCE: Doxorubicin (DOX) induces dose-dependent cardiotoxicity (DIC), which can lead to progressive heart failure and life-threatening arrhythmias. Guizhi Gancao Decoction (GGD), composed of dried twig of Cinnamomum aromaticum Nees (dry weight 12g) and dried roots and rhizomes of Glycyrrhiza uralensis Fisch. ex DC. (dry weight 6g), is a classical formula first recorded by Zhang Zhong-jing in the Shang Han Lun. It has been used for centuries in traditional Chinese medicine (TCM) to treat cardiovascular ailments associated with "heart-yang deficiency". However, its potential efficacy against DIC remains unexplored. AIM OF THE STUDY: This study aimed to evaluate the therapeutic potential of GGD against DIC and to elucidate the underlying mechanisms, with a focus on microtubule-dependent pathways. MATERIALS AND METHODS: DIC models were established in vivo in mice and in vitro in cardiomyocytes using DOX. Interventions included GGD, dexrazoxane (DEX), and paclitaxel (TAX, a microtubule stabilizer). Cardiac structure and function were assessed by serial echocardiography. Cardiomyocyte viability, α-tubulin acetylation, T-tubule integrity, and key proteins (HDAC6, SIRT2, ATAT1, JPH-2, RyR2) expression and localization were evaluated. Cytosolic Ca RESULTS: GGD significantly ameliorated DOX-induced cardiac dysfunction and cardiomyocyte atrophy both in vivo and in vitro. It prevented DOX-induced HDAC6 upregulation, thereby restoring α-tubulin acetylation and microtubule stability. Moreover, GGD, TAX, and Tub A similarly preserved T-tubule integrity, maintained proper JPH-2/RyR2 distribution, and prevented Ca CONCLUSIONS: Our findings suggest that GGD protects against DIC potentially through inhibition of HDAC6-mediated α-tubulin deacetylation, which stabilizes microtubules, ensures T-tubule integrity and calcium-handling protein distribution, and ultimately preserves cardiomyocyte Ca