Abstract TP438: Nanoparticulate Matter Exposure Mediates White Matter Changes in a Murine Model

Abstract

Background: Clinical and epidemiologic studies suggest a relationship between long-term nano-particulate matter (nPM) exposure and white matter injury 1 . Accumulating laboratory evidence suggests that nPM exposure causes inflammation in multiple brain regions 2 . Objective: We sought to study the effects nano-particulate matter exposure on microglia activation and complement upregulation within the corpus callosum in a murine model. Methods: C57 black 6J mice were randomized to re-aerosolized nPM (n=18, nPM <200 nm) or filtered air (n=18) cohorts. Exposures were conducted for a total of 150 cumulative hours. Post-exposure, brains were harvested and immunohistochemical analysis performed. Reactive microglia (IBA-1), reactive astrocytes (GFAP) and C5α deposition (C5α antibody) were quantified in the medial corpus callosum. Results: There were significant differences in IBA-1 cell count staining between the groups (filtered air- 94.7± 18.87; nPM- 158.5 ± 41.69, p<0.05). No differences in GFAP cell count staining existed between the filtered air (677.5 ± 96.09) and nPM mice (656.6 ± 120.3, p=ns). There were significant differences in C5α density staining between filtered air (8.181 ± 3.863) and nPM mice (14.77 ± 5.989, p<0.01). Conclusion: Chronic particulate matter exposure is associated with white matter changes in a murine model. Regional increases in microglia number and C5α deposition suggest an inflammatory mechanism.