Astaxanthin and selenium synergistically ameliorate acute liver injury via transcriptional modulation of Nrf2- and Nfkb1-related pathways.

Acute liver injury (ALI) remains a critical health challenge driven by oxidative stress, inflammation, and apoptosis. This study aimed to evaluate whether astaxanthin (ASX) and/or selenium (Se) can prevent carbon tetrachloride (CCl₄)-induced ALI in rats and to explore the transcriptional regulation of antioxidant, inflammatory, and apoptotic pathways, with particular focus on nuclear factor erythroid 2-related factor 2 (Nrf2), reactive oxygen species (ROS), and nuclear factor kappa-light-chain-enhancer of activated B cells (Nfkb1). Nrf2/ROS/Nfkb1 and Bcl-2-associated X protein (Bax) and B-cell lymphoma 2 (Bcl-2) signaling pathways. Sixty male Sprague-Dawley rats were randomly assigned to ten groups (n = 6): control, SIL (silymarin), ASX (astaxanthin), Se (selenium), ASX + Se (astaxanthin + selenium), CCl4 (carbon tetrachloride), and their corresponding pretreatment counterparts. ALI was induced with a single intraperitoneal CCl4 injection (1 mL/kg). Serum biochemical markers of hepatic function, oxidative and inflammatory mediators, and apoptosis-related genes were quantified. Molecular expression of Nrf2, Nfkb1, Bax, Bcl-2, caspase-3, and related cytokines was assessed. Liver histology was examined to confirm tissue-level alterations. CCl4 administration significantly elevated serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and gamma-glutamyl transferase (GGT) activities, while suppressing antioxidant and cytoprotective mediators, nuclear factor erythroid 2-related factor 2 (Nrf2), superoxide dismutase (sod), and interleukin-10 (IL-10), and upregulating pro-inflammatory and pro-apoptotic markers (nuclear factor kappa-light-chain-enhancer of activated B cells (Nfkb1), cyclooxygenase-2 (COX-2), tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), inducible nitric oxide synthase (iNOS), Bcl-2-associated X protein (Bax), and caspase-3). Histopathology showed necrosis, inflammation, and steatosis. Pretreatment with ASX and/or Se markedly restored biochemical parameters, modulated gene expression toward antioxidant and anti-inflammatory profiles, and significantly improved hepatic architecture, with the combination therapy exerting the most pronounced effects. ASX and Se effectively mitigate CCl4-induced ALI by enhancing antioxidant defense, suppressing inflammation, and inhibiting apoptosis through modulation of key signaling pathways. These findings support their potential as complementary agents for hepatoprotection.