High-fat diet consumption negatively influences closed-head traumatic brain injury in a pediatric rodent model

Traumatic brain injury (TBI) is one of the most common causes of emergency room visits in children, and it is a leading cause of death in juveniles in the United States. Similarly, a high proportion of this population consumes diets that are high in saturated fats, and millions of children are overweight or obese. The goal of the present study was to assess the relationship between diet and TBI on cognitive and cerebrovascular outcomes in juvenile rats. In the current study, groups of juvenile male Long Evans rats were subjected to either mild TBI via the Closed-Head Injury Model of Engineered Rotational Acceleration (CHIMERA) or underwent sham procedures. The animals were provided with either a combination of high-fat diet and a mixture of high-fructose corn syrup (HFD/HFCS) or a standard chow diet (CH) for 9 days prior to injury. Prior to injury, the animals were trained on the Morris water maze for three consecutive days, and they underwent a post-injury trial on the day of the injury. Immediately after TBI, the animals' righting reflexes were tested. Four days post-injury, the animals were euthanized, and brain samples and blood plasma were collected for qRT-PCR, immunohistochemistry, and triglyceride assays. Additional subsets of animals were used to investigate cerebrovascular perfusion using Laser Speckle and perform immunohistochemistry for endothelial cell marker RECA. Following TBI, the righting reflex was significantly increased in TBI rats, irrespective of diet. The TBI worsened the rats' performance in the postinjury trial of the water maze at 3 h, p(injury) < 0.05, but not at 4 days post-injury. Reduced cerebrovascular blood flow using Laser Speckle was demonstrated in the cerebellum, p(injury) < 0.05, but not foci of the cerebral cortices or superior sagittal sinus. Immunoreactive staining for RECA in the cortex and corpus callosum was significantly reduced in HFD/HFCS TBI rats, p < 0.05. qRT-PCR showed significant increases in APOE, CREB1, FCGR2B, IL1B, and IL6, particularly in the hippocampus. The results from this study offer robust evidence that HFD/HFCS negatively influences TBI outcomes with respect to cognition and cerebrovascular perfusion of relevant brain regions in the juvenile rat.