Background and Objectives: 5-Fluorouracil (5-FU) is a widely prescribed and effective chemotherapeutic drug, but its cardiotoxic side effects pose a significant challenge to its use. Identifying a protective agent that does not affect its anticancer efficacy is essential. Our study aimed to investigate the cardioprotective effect of N-acetyl cysteine (NAC) against 5-FU-induced cardiac injury and to elucidate the underlying mechanisms. Materials and Methods: This study included four experimental groups, each with eight rats (n = 8): Group I (control group), Group II (NAC group), Group III (5-FU group), and Group IV (combined group 5-FU+NAC). Cardiac enzymes, oxidative stress, inflammatory, and apoptotic markers were investigated, and cardiac sections from the different groups were histologically examined. Results: Co-treatment of 5-FU with NAC resulted in significantly lower levels of cardiac enzymes (alanine transaminase (ALT) by 62.1%, aspartate transaminase (AST) by 73.6%, lactate dehydrogenase (LDH) by 55.8%, and creatine kinase (CK) by 57.3%) compared to the 5-FU group, along with marked improvements in heart tissue histology. Additionally, NAC enhanced the activity of cardiac antioxidant enzymes (superoxide dismutase (SOD) by 295.6%, catalase (CAT) by 181%, and glutathione peroxidase (GPx) by 320.9%) while decreasing malondialdehyde (MDA) by 51.1%, a marker of membranous lipid peroxidation. This might be due to significant upregulation of the nuclear factor erythroid-2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway at the gene and protein levels. The combined treatment significantly decreased the gene expression of the toll-like receptor 4 (TLR4)/nuclear factor kappa-light-chain-enhancer of activated B-cell (NF-κB) pathway. Furthermore, it downregulated the protein levels of inflammatory markers, including tumor necrosis factor-alpha (TNF-α) by 29.9%, interleukin-1 beta (IL-1β) by 21.9%, and interleukin-6 (IL-6) by 49.3%. Moreover, it upregulated the antiapoptotic marker B-cell lymphoma 2 (Bcl-2) protein levels by 269% and decreased apoptotic indicators Bcl-2-associated protein x (Bax) by 57.9% and caspase-3 by 30.6% compared to the 5-FU group. Conclusions: This study confirmed that NAC prevented the cardiotoxic effect of 5-FU through its antioxidant, anti-inflammatory, and antiapoptotic properties, suggesting its potential application as an adjuvant therapy in chemotherapy to alleviate 5-FU-induced cardiotoxicity.

Herein, we measured the antidiabetic and nephroprotective effects of the sodium–glucose cotransporter-2 inhibitor (empagliflozin; SGLT2i) and synthetic active vitamin D (paricalcitol; Pcal) mono- and co-therapy against diabetic nephropathy (DN). Fifty mice were assigned into negative (NC) and positive (PC) control, SGLT2i, Pcal, and SGLT2i+Pcal groups. Following establishment of DN, SGLT2i (5.1 mg/kg/day) and/or Pcal (0.5 µg/kg/day) were used in the designated groups (5 times/week/day). DN was affirmed in the PC group by hyperglycaemia, dyslipidaemia, polyuria, proteinuria, elevated urine protein/creatinine ratio, and abnormal renal biochemical parameters. Renal SREBP-1 lipogenic molecule, adipokines (leptin/resistin), pro-oxidant (MDA/H₂O₂), pro-inflammatory (IL1β/IL6/TNF-α), tissue damage (iNOS/TGF-β1/NGAL/KIM-1), and apoptosis (TUNEL/Caspase-3) markers also increased in the PC group. In contrast, renal lipolytic (PPARα/PPARγ), adiponectin, antioxidant (GSH/GPx1/SOD1/CAT), and anti-inflammatory (IL10) molecules decreased in the PC group. Both monotherapies increased insulin levels and mitigated hyperglycaemia, dyslipidaemia, renal and urine biochemical profiles alongside renal lipid regulatory molecules, inflammation, and oxidative stress. While SGLT2i monotherapy showed superior effects to Pcal, their combination demonstrated enhanced remedial actions related to metabolic control alongside renal oxidative stress, inflammation, and apoptosis. In conclusion, SGLT2i was better than Pcal monotherapy against DN, and their combination revealed better nephroprotection, plausibly by enhanced glycaemic control with boosted renal antioxidative and anti-inflammatory mechanisms.