ABSTRACT
Traumatic Brain Injury (TBI) is known to result in oxidative stress, and as variation at the Apolipoprotein E (APOE) gene has been shown to influence outcome following TBI, but through as yet unclear mechanisms, we used transgenic APOE mouse models to examine the relationship between APOE genotype and oxidative stress following TBI. We administered a controlled cortical impact (CCI) injury or sham injury to transgenic mice expressing either human APOE3 or APOE4 on a murine APOE-deficient background. RNA was prepared from the ipsilateral hippocampi and cortices retrieved at 24 h and 1 month post-TBI. Microarray analysis was performed on unpooled samples from three mice per group to determine the genomic response to TBI and to specifically investigate the response of genes involved in oxidative stress mechanisms. Our data demonstrated TBI-induced expression of many more anti-oxidant related genes in the APOE3 mice, suggesting a potential anti-oxidative role for ApoE3 compared to ApoE4. However, in an additional cohort of mice we isolated the ipsilateral hippocampi, cortices, and cerebella at 1 month after TBI or sham injury for immunohistochemical analysis of markers of oxidative stress: the formation and presence of carbonyls (indication of general oxidative modification), 3-nitrotyrosine (3NT; specific to protein modification), or 4-hydroxyl-2-nonenal (HNE; specific to lipid peroxidation). Although we observed significant increases in all three markers of oxidative stress in response to injury, and genotype was a significant factor for carbonyl and 3NT, we found no significant interaction between genotype and injury. This may be due to the overwhelming effect of injury compared to genotype in our ANOVA, but nonetheless suggests that an influence on oxidative stress response is not the primary mechanism behind the APOE-genotype dependent effects on outcome following TBI.
Subject(s)
Apolipoproteins E/genetics , Brain Injuries/metabolism , Oxidative Stress , Animals , Apolipoprotein E3/genetics , Apolipoprotein E4/genetics , Genotype , Humans , Mice , Mice, Transgenic , Oligonucleotide Array Sequence Analysis , Oxidation-ReductionABSTRACT
The different alleles of the apolipoprotein E gene (APOE-gene, ApoE-protein) have been reported to influence recovery after traumatic brain injury (TBI) in both human patients and animal models, with the e4 allele typically conferring poorer prognosis for recovery. How the E4 allele, and consequently the ApoE4 isoform, affects recovery is unknown, but proposed mechanisms include neurogenesis, inflammatory response and amyloid processing or metabolism. Using the controlled cortical impact (CCI) model of brain injury and microarray technology we have characterized the genomic response to injury in the brains of APOE2, APOE3 and APOE4 transgenic mice and identified quantitatively and qualitatively significantly different profiles of gene expression in both the hippocampus and the cortex of the APOE3 mice compared to APOE4. The observed gene regulation predicts functional consequences including effects on inflammatory processes, cell growth and proliferation, and cellular signaling, and may suggest that the poor recovery post-TBI in APOE4 animals and human patients is less likely to result from a specific activation of neurodegenerative mechanisms than a loss of reparative capability.
Subject(s)
Apolipoprotein E2/genetics , Apolipoprotein E3/genetics , Apolipoprotein E4/genetics , Brain Injuries/genetics , Cerebral Cortex/physiopathology , Hippocampus/physiopathology , Animals , Brain Injuries/physiopathology , Databases, Genetic , Female , Gene Expression Profiling , Gene Expression Regulation , Genotype , Humans , Mice , Mice, Transgenic , Oligonucleotide Array Sequence Analysis , Protein Isoforms/genetics , Signal Transduction/genetics , SoftwareABSTRACT
Pea proteins have been considered for the introduction into the human diet only recently. This protein source was tested on nutritional and digestive parameters in heteroxenic male Fischer rats inoculated with a human faecal microflora from a methane producer. Compared to soybean proteins, pea proteins have similar effects on the rat's endogenous and bacterial digestive patterns. Compared to the pea proteins, a diet containing a standard meat meal enhanced the pH and the production of ammonia, while a lyophilized beef meat enhanced that of urea. The diet containing the standard meat decreases short-chain fatty acids and modifies the ratio of caecal short-chain fatty acids. Both animal diets decreased the specific activities of pancreatic proteases such as chymotrypsin (EC 3.4.21.1), trypsin (EC 3.4.21.4), and carboxypeptidase A (EC 3.4.17.1) when compared to the diet containing the pea isolate. In conclusion, the whole composition of the diet, more than the origin of the dietary protein, influences the rat's digestive pattern.
