The Impact of H1–H4 Receptor Antagonists on the Levels of Selected Oxidative Stress Markers in Liver and Muscle Tissue in an Animal Model of Colitis

<b>Background/Objectives:</b> The global prevalence and incidence of inflammatory bowel diseases have risen in the past two decades. Among them, Crohn's disease and ulcerative colitis are still challenging to treat due to vascular and proliferative alterations. Studies in rats suggest that blocking histamine receptors (H1-H4) can improve colitis progression. However, the specific histamine receptor responsible for this effect remains debated. The experiment aimed to assess the role of specific histamine receptor subtypes in colitis development, focusing on oxidative stress markers in the liver and skeletal muscle. <b>Methods:</b> The study involved 60 adult male Wistar rats, divided into control and colitis experimental groups. Colitis was induced through intracolonic administration of 2,4,6-trinitrobenzenesulfonic acid. Animals in both experimental groups received intramuscular injections of NaCl (non-treated, NT) or H1, H2, H3, and H4 receptor antagonists (10 study subgroups in total). On day eight, the animals were re-anesthetized and euthanized via exsanguination. Then, liver and skeletal muscle (<i>m. soleus</i>) samples were collected for analysis of oxidative stress markers. <b>Results:</b> The analyses of skeletal muscle samples showed that using the H1 and H2 receptor antagonists increased superoxide dismutase (SOD) and catalase (CAT) activities, as well as parameters related to glutathione metabolism (reduced glutathione (GSH), glutathione S-transferase (GST)) in rats from the control groups, indicating enhanced antioxidant defense. In rats with chemically induced colitis, we observed that H1 receptor antagonists elevated CAT activity, whereas β-esterase (β-EST) activity remained elevated across all colitis subgroups. In the liver, histamine receptor antagonists produced receptor-specific redox effects: the H2 receptor antagonist reduced oxidative damage (malondialdehyde (MDA)); the H1 receptor antagonist attenuated SOD hyperactivity, but depleted GSH; and the H4 receptor antagonist increased GSH while elevating MDA. Chemically induced colitis increased α- and β-EST activities, whereas administration of the H1 or H3 antagonist reduced β-EST levels. <b>Conclusions:</b> Histamine receptor antagonists modulated oxidative stress responses in both liver and skeletal muscle tissues in a receptor-dependent manner. Among them, the H2 receptor antagonist most effectively mitigated hepatic oxidative injury, highlighting its potential as a therapeutic target in colitis-associated systemic oxidative stress.