| Description: |
Background: Methotrexate (MTX), a widely used antifolate agent in oncology and autoimmune disorders, has been increasingly associated with neurotoxic effects in the central nervous system. Hyperbaric oxygen (HBO) therapy has emerged as a potential neuroprotective approach through modulation of oxidative stress and cellular stress-response pathways, including autophagy and apoptosis. However, the region-specific effects of MTX and HBO on the autophagy–apoptosis axis within the hippocampus remain incompletely understood. Materials and Methods: Adult male Sprague Dawley rats were randomly assigned to four groups: SALINE, HBO, MTX, and MTX + HBO. Hippocampal dentate gyrus (DG) and cornu ammonis (CA) subregions were analyzed. Immunohistochemistry was used to assess autophagy- and apoptosis-related markers, including LC3, Beclin-1, p62/SQSTM1, and cleaved Caspase-3 (Asp175). DNA fragmentation was evaluated using the TUNEL assay. Quantitative analyses were performed using animal-based mean values, and statistical comparisons were conducted using one-way ANOVA followed by Tukey post hoc testing (p < 0.05). Results: MTX administration was associated with increased LC3 and Beclin-1 immunoreactivity, indicating activation of early-phase autophagy-related signaling, accompanied by p62 accumulation and elevated Caspase-3 immunoreactivity, a pattern consistent with disrupted downstream autophagic processing and enhanced apoptotic signaling. HBO treatment alone induced a more limited increase in LC3 and Beclin-1 while reducing basal p62 and Caspase-3 levels, suggesting a modulatory and adaptive cellular response rather than overt stress activation. In the MTX + HBO group, p62 and Caspase-3 levels were reduced relative to MTX alone, indicating partial attenuation of MTX-associated cellular stress. TUNEL labeling was negative in all groups, suggesting that apoptotic processes were captured at an early or pre-fragmentation stage. Conclusions: The present findings indicate that MTX exposure is associated with preserved ... |