Establishment of an In-Vitro Alzheimer’s Disease Model Through Amyloid-β(25–35) Neurotoxicity in SH-SY5Y Cells

Background: Alzheimer’s disease (AD) is a progressively neurodegenerative condition marked by amyloid-β (Aβ) accumulation and neuronal death. Despite substantial research, effective disease-modifying medications remain unavailable, underlining the need for dependable preclinical models to test novel therapeutic techniques. In order to enable future screening of possible anti-Alzheimer's drugs, the current work set out to create an in vitro Alzheimer's disease model with an ideal dose of Aβ (25–35) that causes repeatable neuronal cytotoxicity in SH-SY5Y cells. Methods: The experiment was conducted at Ziauddin University, Karachi. SH-SY5Y neuroblastoma cells were treated to Aβ (25–35) at doses ranging from 0–80 μM during 24 hours. Cell viability was assessed using the MTT test, and the concentration that reduced survival by 50–60% was determined as the best cytotoxic dose for model development. To confirm cell death and observe membrane integrity and nuclear morphology, cells had been stained with propidium iodide (PI) and DAPI, then studied by fluorescence microscopy. Results: Aβ (25-35) treatment produced a clear, concentration-dependent reduction in viability. At 40 μM, cell survival decreased to ~54%, meeting the target threshold of 50–60% cytotoxicity. Fluorescence microscopy confirmed thesefindings, with PI staining highlighting membrane-compromised cells and DAPI revealing nuclear condensation and fragmentation. Together, these outcomes validate 40 μM Aβ (25–35) as a reliable concentration for establishing a standardized in vitro model of AD. Conclusion: This study created an in vitro Alzheimer's disease model utilizing SH-SY5Y cells exposing them to Aβ(25-35), with 40 μM causing ~50-60% cytotoxicity and neurotoxicity. This model may serve as a core basis for future in vitro AD research. DOI: https://doi.org/10.59564/amrj/03.04/013