Cardioprotective Effects of Coupled SH/NO System Modulators in a Rat Model of Doxorubicin-Induced Heart Failure

Background: The high prevalence of chronic heart failure (CHF) in industrialized countries, alongside its grave consequences—including increased mortality, disability, functional impairment, and reduced quality of life—underscores the urgent need to optimize core medical therapy. In this regard, metabolic cardioprotectants are of particular interest, as their action is aimed at interrupting or mitigating the cascade of adverse metabolic reactions and enhancing the compensatory and adaptive mechanisms of the heart. The aim of this study was to evaluate the effect of sulfur-containing pharmacological agents—namely, N-acetylcysteine (NAC), Heptral, Thiotriazoline, and Angiolin—on selected parameters of the NO and thiol-disulfide systems in the hearts of rats with experimental doxorubicin-induced CHF, followed by an assessment of their cardioprotective efficacy. Methods: CHF was modeled in 70 male Wistar rats weighing 180–190 g by intraperitoneal administration of doxorubicin at a cumulative dose of 15 mg/kg, divided into 6 injections over 14 days. The investigated drugs were administered intragastrically once daily as a suspension in 1% starch mucilage for 30 days following the 14-day doxorubicin protocol: Angiolin ([(S)-2,6-diaminohexanoic acid 3-methyl-1,2,4-triazolyl-5-thioacetate], 100 mg/kg), Thiotriazoline (morpholinium thiazotate, 100 mg/kg), NAC (100 mg/kg), Heptral (S-adenosylmethionine, 100 mg/kg), and Mildronate (250 mg/kg). In the rat myocardium, key components of the NO and thiol-disulfide systems—iNOS, eNOS, nitrotyrosine, stable NO metabolites, glutathione peroxidase-4 (GPX4), glutathione reductase (GR), reduced glutathione (GSH), and oxidized glutathione (GSSG)—were determined using enzyme-linked immunosorbent assay (ELISA), biochemical assays, and real-time PCR. In serum, cardio-specific biomarkers were measured, including the creatine kinase-MB isoenzyme (CK-MB), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and soluble ST2 protein (sST2). Results: It was established that on day 45 following the 14-day doxorubicin administration, alongside a significant elevation in CK-MB, NT-proBNP, and sST2 levels (p < 0.05), there was a concurrent upregulation of iNOS mRNA expression, iNOS protein levels, and nitrotyrosine formation, accompanied by a downregulation of eNOS mRNA expression, eNOS protein levels, and stable NO metabolites (p < 0.05). Furthermore, heart tissue from CHF rats exhibited depletion of the glutathione pool within the thiol-disulfide system, characterized by decreased GPX4, GR, and GSH levels alongside increased GSSG concentrations (p < 0.05). Course administration of the test pharmacological agents to experimental animals post-CHF induction resulted in an improvement in the evaluated parameters of the coupled NO and thiol-disulfide systems, as well as overall cardioprotection. The study analysis demonstrated that Angiolin was statistically superior to Heptral and Mildronate, whereas Thiotriazoline and NAC outperformed Mildronate. Conclusions: These findings confirm the potential cardioprotection provided by modulators of the SH/NO system. Based on these results, further preclinical investigation of Angiolin as a promising cardioprotective agent for CHF is experimentally substantiated.