Investigating the Effects of Short-Term E-Cigarette Exposure on Osseous Tissue in the House Mouse, Mus musculus

Early data suggests that e-cigarette usage is producing negative health impacts similar to traditional cigarette smoking, yet insufficient data exists on the effects of exposure to e-cigarette vapor on bone integrity. This study explored the consequences of short-term e-cigarette exposure on bone tissue in the house mouse, Mus musculus. I hypothesized that exposed mice would show elevated inflammatory protein markers. To investigate my hypothesis, I developed and optimized histological protocols in two phases. Phase one entailed dissection, decalcification, embedding, sectioning, and staining. Tibias from mice exposed to strawberry flavored e-cigarette fumes (Elf Bar) and control animals were dissected. A decalcification protocol was developed to remove mineralized matrix and increase paraffin wax permeability. Tissue samples were embedded in paraffin, sectioned with a rotary microtome, and mounted. A staining protocol was followed to allow visualization of cellular morphology by highlighting nuclear (hematoxylin) and cytoplasmic (eosin) regions. Phase two will use established protocols for immunohistochemistry (IHC) and imaging software to compare integrated density values of localized proteins involved in osteoclastosis (mitochondrial pyruvate carrier – 1 (MPC-1) and macrosialin (CD68). MPC-1 transports pyruvate into the mitochondria for energy production and CD68 is a transmembrane protein located in lysosomal and endosomal compartments of osteoclasts. IHC utilizes an antibody cascade based on an enzymatic reaction using the substrate diaminobenzidine (DAB) chromogen which induces a color change-based oxidation reaction to visualize target proteins. Data collected in this study will contribute to the growing body of evidence summarizing the potential health impacts of e-cigarette usage.