β-Amyloid peptide modulates peripheral immune responses and neuroinflammation in rats.

Alzheimer's disease (AD) is characterized by immune system dysregulation, impacting both central and peripheral immune responses. The study aimed to investigate the mechanism behind the neurotoxic effects of β-amyloid (Aβ) peptide in the rat brain including the study of neuroinflammation, neurodegeneration, and alterations in peripheral immune responses (PIR). The neuroinflammation brought on by Aβ_1-42 and is unknown to influence PIR. Animal models were prepared, after 28 days, control, sham, and treated rats were anaesthetized and inflammatory markers of hippocampus and serum levels (reactive oxygen species, nitrite, tumor necrosis factor-α, and interleukin-1β), and some markers of PIR (splenic mononuclear cells or MNC, cytotoxicity and phagocytic index of the white blood cells leukocyte adhesion inhibition index or LAI), as well as polymorphonuclear cells of the spleen, were assessed. In addition to changes in peripheral immune responses, the present study found that AD rats had higher blood levels of inflammatory markers. Based on the study, the immune system irregularities observed in AD rats in the peripheral regions might be connected to neuroinflammation, which is facilitated by a compromised blood-brain barrier. Hence, it is viable to propose that the neuroinflammatory condition in rats with Aβ-induced AD could modify immune responses in the peripheral areas with significantly higher levels of inflammatory cytokines markers in the hippocampal tissue in Aβ-injected AD rats.