APP/PS1 Mice

The APP/PS1 mouse is a transgenic mouse model commonly used in the study of AD. The mouse co-expresses two human transgenes: the mutated human amyloid precursor protein (APP) and L166P mutated human presenilin 1 (PSEN1) genes. This causes the mouse to over express human APP, leading to the accumulation of Aβ40 and Aβ42 and subsequently plaque deposition as the mouse ages. The physiological and cognitive impairments typically seen in human AD patients are also seen in these mice, such as decreased synaptic plasticity, neuronal loss, and memory loss. The ability to treat these mice with drugs, behavioral tests, and molecular quantification methods making them extremely useful in the study of AD (Gengler et al., 2010).

Morris Water Maze

The Morris water maze (MWM) is a test of spatial learning and memory where animal models are placed in a pool of opaque water. The animal can freely swim around until they discover a hidden platform beneath the surface of the water, allowing them to rest. The animals are then repeatedly placed back into the pool, measuring several variables that indicate their ability to learn from previous attempts and memorize their previous paths (Nunez, 2008). Watch the video below to get a better understanding of how this experiment works:

Immunofluorescent Staining

Immunofluorescent staining is a highly versatile immunochemical technique that allows the visualization of proteins, antigens, and many other components that may be found in various tissues. This is done through the use of fluorophore-antibodies that are specific to the component of interest (Im et al., 2019). For example, in the study of NTP researchers employed immunofluorescent stating used GFAP and Iba1 specific antibodies to identify microglia and astrocytes in brain tissue. Watch the video below to learn more about the process of immunofluorescent staining:

Enzyme-Linked Immunosorbent Assay (ELISA)

ELISA is widely used in research to detect the concentrations of various substances including proteins and peptides. It uses antibodies that bind antigens specific to the substance of interest, allowing researchers to identify the abundance of antigen-antibody complexes, and therefore the concentration of that substance (Aydin, 2015). Samples from the hippocampus and cortex of the WT and TG mice were used in ELISA to observe changes in the concentrations of Aβ40/42, BDNF, and pro-inflammatory cytokines before and after treatment with NTP. Watch the video below to learn more about how ELISA works:

Western Blot

The Western blot is a common lab technique used in the identification and quantification of specific proteins. The process generally involves the separation of proteins based on weight and charge using gel electrophoresis. Antibodies are then used to bind the proteins, forming complexes that are detected with chemiluminescence imaging. These complexes show up as “bands” at varying opacity depending on molecular weight and are compared to a reference protein such as β-actin. (Kim, 2017). The research by Fang et al. used a sample from the hippocampus and cortex of mice to detect different levels of NF-κB pathway elements before and after NTP treatment. The diagram below outlines their procedure:

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