The Impact of Cocaine on Inflammatory Markers in SIM-A9 Microglial Cells

Substance use disorders are conditions in which an individual continues to use a drug or other substance despite adverse consequences to their health and well-being. It has been hypothesized that inflammation within the central nervous system plays a critical role in the development of substance use disorders. The resident macrophages in the brain, also known as microglia, release markers of inflammation in response to injury or infection. A better understanding of the inflammatory response mediated by microglia in response to drugs of misuse can validate this hypothesis and help guide drug development. In the current studies, the microglia cell line SIM-A9 was treated with the negative control of phosphate buffered saline, cocaine at different concentrations, or the positive control lipopolysaccharide. After incubation with these treatments for 24 hours, RNA extraction was performed and followed by cDNA synthesis. The cDNA was then used for qPCR analysis to determine the change in expression of the inflammatory markers IL-1β and TNF-α. There were significant between-group differences for both IL-1β (P<0.0001) and TNF-α (P =0.0395). In post-hoc analyses, there were significant increases in IL-1β with the higher dose of cocaine compared to phosphate buffered saline but increases in TNF-α with cocaine compared to other groups were non-significant. Overall, these preliminary data indicate that certain inflammatory markers, principally IL-1β, are elevated on the SIM-A9 microglia cell line in response to cocaine. Future studies are needed to determine if similar responses exist in vivo.