A comprehensive method of isolating proteins from serum, cerebrospinal fluid, and hippocampal neurons in rats for proteomic profiling using the LC-MS/MS platform

Neurology research largely utilizes rat brains due to their structural and functional similarities to humans, making them valuable models for studying various neurological conditions. There is growing interest in investigating diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), cognition, and other mental health-related disorders. This has created a need for a comprehensive, combined, and easy-to-follow method to isolate serum, cerebrospinal fluid (CSF), and hippocampal neurons. The hippocampus, responsible for learning and memory, is affected by various neurological and psychiatric disorders. However, obtaining samples like CSF and hippocampal neurons is challenging, especially from small animals like rats. Currently, there is no efficient method for isolating these samples altogether from a single animal, and its use in downstream applications has not been thoroughly tested. We have developed a comprehensive and streamlined method for isolating serum, CSF, and hippocampal neurons from a single animal, suitable for downstream applications such as proteomics and biomarker research. This method involves using high-speed centrifugation instruments and density gradient centrifugation, which are easy to follow. The isolated proteins were identified through mass spectrometry. Our method has been successfully tested for high-throughput applications with small sample volumes, demonstrating its clinical utility. With our simplified approach, proteins in serum, CSF, and neural cells can be studied simultaneously. The method achieves ease of use, cost-effectiveness, and reproducibility, thereby facilitating a better understanding of neurological disorders.