Alcohol Exposure Post-Traumatic Brain Injury Worsens Neurobehavioral Outcomes in Rats; Potential Role of Bioenergetic Alterations at the Site of Injury

Traumatic brain injury (TBI) is a critical global health issue, leading to death and disability for millions annually. Alarmingly, approximately one-third of individuals with TBI consume alcohol in moderate to heavy amounts after their injury. Post-injury alcohol use hinders the recovery of cognitive functions, particularly those governed by the prefrontal cortex. Preclinical studies reveal that both TBI and alcohol disrupt cellular energy metabolism and mitochondrial function. However, the specific effects of alcohol consumption on brain energy metabolism and related behavioral changes following TBI remain unclear. We hypothesize that alcohol-induced alterations in bioenergetics may exacerbate, delay, or impair neurobehavioral recovery post-TBI. This study aimed to determine if post-TBI alcohol exposure amplifies mitochondrial bioenergetic deficits at the site of injury and whether this is associated with impairments in spatial working memory. Adult male Wistar rats were randomly assigned to one of four groups: i) Sham, ii) Sham + ethanol (EtOH), iii) TBI, or iv) TBI + EtOH. All rats underwent craniotomy three days before TBI induction using lateral fluid percussion (LFP). Sham animals were anesthetized but did not undergo TBI. Two days post-TBI, animals received intraperitoneal EtOH (2.0 g/kg) daily for five days. Behavioral tests, including the Y-Maze spontaneous alternation and open field tests, were conducted on day 6, six hours after the final EtOH injection. On day 7, animals were euthanized, and brains were processed to obtain punches near-injury site and prefrontal cortex (PFC) for mitochondrial respiration analysis using the XFPro Extracellular Flux Analyzer. Data show reduced spontaneous alternations; indicating spatial working memory deficits, in animals in the EtOH, TBI, and TBI+EtOH groups compared to Sham controls. In addition, we observed significantly reduced total distance traveled during Y-Maze testing in TBI+EtOH animals. Open field-test showed that EtOH and TBI+EtOH groups had fewer entries into the inner zone compared to Sham animals, suggesting increased anxiety-like behaviors. Mitochondrial respiration measurements demonstrated reduced oxygen consumption rates (OCR) and extracellular acidification rates (ECAR) in PFC punches from EtOH and TBI+EtOH groups relative to Sham controls. Similarly, injury site punches from TBI, EtOH, and TBI+EtOH groups showed significant reductions in mitochondrial OCR and oligomycin-induced (maximal) ECAR compared to Sham animals. These results suggest that post-TBI alcohol exposure produces mitochondrial bioenergetics deficits in the PFC and injury site, that may contribute to delayed cognitive recovery and heightened anxiety. Ongoing studies aim to elucidate the underlying mechanisms, focusing on oxidative stress, mitochondrial dynamics, and ferroptosis, with the goal of identifying therapeutic targets to mitigate these detrimental effects. Supported by NIH/NIAAA R01 AA025792 (PEM) and T32 AA007577 (PEM). This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.