Doxorubicin Dose-Dependent Impact on Physiological Balance—A Holistic Approach in a Rat Model

Abstract

Doxorubicin (DOX) is commonly used in several chemotherapies to treat various cancers, but it is known to cause cardiotoxicity and cardiac symptoms. Autonomic dysfunction is thought to contribute to the cardiotoxic effects of DOX, but the specific dose required to disrupt homeostatic processes is still unclear and is influenced by numerous factors. This study aimed to investigate how the DOX dosage affects autonomic function and physiological parameters, to elucidate the neurocardiac mechanisms underlying the observed cardiovascular side effects. Wistar rats were treated with DOX for four weeks and divided into three dosing groups: DOX8 (2 mg/kg/week), DOX16 (4 mg/kg/week), and DOX20 (5 mg/kg/week). A control group received NaCl 0.9% saline (1 mL/kg/week). In an acute experiment, we recorded blood pressure (BP), electrocardiogram, heart rate (HR), and respiratory rate (RF). Baroreflex gain and chemoreflex sensitivity were calculated, and cardiac tissue was analyzed with picrosirius histochemistry to measure collagen content. Our results showed that the LF/HF ratio, indicative of autonomic activity, was altered along with hypotension and bradycardia at a cumulative DOX dose threshold of 16 mg/kg. We observed a positive correlation between DOX dose and BP, HR, urinary norepinephrine, LF/HF ratio, and fibrotic heart area. Lower LF/HF ratios were associated with high DOX doses, reflecting drug-induced impairment of autonomic control of HR. This study provides valuable insights into the dose-dependent effects of DOX on physiological parameters and the development of cardiovascular dysfunction. These findings are critical, which is important for optimizing the management and therapeutic strategies for patients undergoing DOX-based chemotherapy.

Different Mechanisms in Doxorubicin-Induced Cardiomyopathy: Impact of BRCA1 and BRCA2 Mutations

“…Tipping the redox balance, as in antioxidant deficiency, easily renders cardiac tissues vulnerable to oxidative stress. Indeed, Dox impairs the antioxidants' bioavailability in cardiomyocytes, depending on the duration and dosage of Dox exposure [51]. Conversely, increasing antioxidants' activity enhances the cells' redox capacity, obstructs free radical-related injury to DNA, and attenuates DIC [52,53].…”

Ameliorative impacts of propolis against testicular toxicity promoted by doxorubicin

“…G1: (Control) treated daily with 0.5 mL/injection of physiological saline solution. G2: DOX was administered at 4 mg/kg/weekly injection into the peritoneal cavity [18]. G3: (DOX + propolis) treated with a weekly injection of 4 mg/kg DOX and a daily oral dose of 30 mg/kg propolis using a stomach tube.…”