The neuroprotection of deproteinized calf blood extractives injection against Alzheimer's disease via regulation of Nrf-2 signaling

Alzheimer’s disease (AD) is characterized by cognitive decline due to the accumulation of extracellular β-amyloid (Aβ) plaques and neurofibrillary tangles in the brain, which impair glutamate (Glu) metabolism. Deproteinized Calf Blood Extractive Injection (DCBEI) is a biopharmaceutical that contains 17 types of amino acids and 5 types of nucleotides. In this study, we found that DCBEI pretreatment reduced L-Glu-dependent neuroexcitation toxicity by maintaining normal mitochondrial function in HT22 cells. DCBEI treatment also reduced the expression of pro-apoptosis proteins and increased the expression of anti-apoptosis proteins. Furthermore, DCBEI attenuated AD-like behaviors (detected via the Morris water maze test) in B6C3-Tg (APPswePSEN1dE9)/Nju double transgenic (APP/PS1) mice; this effect was associated with a reduction in the amount of Aβ and neurofibrillary tangle deposition and the concomitant reduction of phospho-Tau in the hippocampus. Metabonomic profiling revealed that DCBEI regulated the level of neurotransmitters in the hippocampus of APP/PS1 mice. Label-free proteomics revealed that DCBEI regulated the expression of Nrf-2 and its downstream targets, as well as the levels of phospho-protein kinase B and mitogen-activated protein kinase. Together, these data show that DCBEI can ameliorate AD symptoms by upregulating Nrf2-mediated antioxidative pathways and thus preventing mitochondrial apoptosis.