Immunolocalization of Two Inflammatory Chemicals (IL-1 and IBA1) in the Brain Tissue of Mice Exposed to E-Cigarettes

E-cigarette usage has steadily increased over the years with a common perception that vaping is a safer alternative compared to cigarette smoking. Nonetheless, there is increasing evidence that e-cigarettes are far from harmless and can pose many potential health challenges. We designed a four-phase project to determine the effects of e-cigarette exposure on histological morphology and the presence of two inflammatory chemicals, interleukin-1 (IL-1) and ionized calcium-binding adaptive molecule (IBA1) in murine brain tissue. In Phase I, 64 animals were divided into a control group and three treatment groups (strawberry, mint, and tropical). Control animals were exposed to clean air and treatment animals were exposed to the vapor of one of the three e-cigarette flavors, each containing the same nicotine content. In Phase 2, we processed experimental tissues using basic histological techniques (fixation, embedding, sectioning, mounting, and hematoxylin/eosin staining) to evaluate tissue morphology. In Phase 3, we optimized an immunocytochemical protocol to localize IL-1 and IBA1 in the cerebellum, hippocampus, and choroid plexus. Immunohistochemistry utilizes antibodies to localize and assess protein expression while preserving the composition and structure of the tissue. Thus, in the current study, our objective is to investigate the presence of inflammatory markers in three specific brain regions which will allow future research (Phase 4) to focus on a quantitative analysis of morphological changes and immunohistochemical staining intensity.