Behavioral and inflammatory response in animals exposed to a low-pressure blast wave and supplemented with β-alanine

Abstract

This study investigated the benefit of β-alanine (BA) supplementation on behavioral and cognitive responses relating to mild traumatic brain injury (mTBI) and post-traumatic stress disorder (PTSD) in rats exposed to a low-pressure blast wave. Animals were fed a normal diet with or without (PL) BA supplementation (100 mg kg−1) for 30-day, prior to being exposed to a low-pressure blast wave. A third group of animals served as a control (CTL). These animals were fed a normal diet, but were not exposed to the blast. Validated cognitive-behavioral paradigms were used to assess both mTBI and PTSD-like behavior on days 7–14 following the blast. Brain-derived neurotrophic factor (BDNF), neuropeptide Y, glial fibrillary acidic protein (GFAP) and tau protein expressions were analyzed a day later. In addition, brain carnosine and histidine content was assessed as well. The prevalence of animals exhibiting mTBI-like behavior was significantly lower (p = 0.044) in BA than PL (26.5 and 46%, respectively), but no difference (p = 0.930) was noted in PTSD-like behavior between the groups (10.2 and 12.0%, respectively). Carnosine content in the cerebral cortex was higher (p = 0.048) for BA compared to PL, while a trend towards a difference was seen in the hippocampus (p = 0.058) and amygdala (p = 0.061). BDNF expression in the CA1 subregion of PL was lower than BA (p = 0.009) and CTL (p < 0.001), while GFAP expression in CA1 (p = 0.003) and CA3 (p = 0.040) subregions were higher in PL than other groups. Results indicated that BA supplementation for 30-day increased resiliency to mTBI in animals exposed to a low-pressure blast wave.

Effects of β-alanine supplementation on physical performance, cognition, endocrine function, and inflammation during a 24 h simulated military operation

“…These results were not consistent with recent animal studies suggesting that when BA ingestion occurs prior to stressful stimuli, elevations in brain carnosine content is associated with an increased resiliency to various stressors by reducing the inflammatory response (Hoffman et al. , ). Whether elevations in muscle carnosine content has similar anti‐inflammatory or muscle protective properties is not well‐understood.…”

“…These elevations also appear to increase the expression of BDNF (Murakami and Furuse ; Hoffman et al. , ), which may promote synaptic plasticity and neurogenesis (Wetmore et al. ; Figurov et al.…”

“…) and a low‐pressure blast wave (Hoffman et al. ) respectively. The efficacy and resiliency demonstrated in these studies were attributed to elevations in both muscle and brain carnosine (β‐alanyl‐L‐histidine).…”

“…), potentially reducing neurodegeneration associated with the inflammatory response to stress, leading to improved cognitive function and mood states (Thomas and Russo ; Murakami and Furuse ; Hoffman et al. , ). BA supplementation has been previously demonstrated to increase brain carnosine concentrations in murine models (Murakami and Furuse ; Hoffman et al.…”

“…Elevations in brain carnosine also appear to increase the expression of brain‐derived neurotropic factor (BDNF) in the hippocampus and cerebral cortex (Murakami and Furuse ; Hoffman et al. , ). BDNF plays a key role in brain health by promoting synaptic plasticity and neurogenesis (Wetmore et al.…”