One month of PBM therapy led to increased Aβ plaque deposition, and larger average size of non-microglia associated plaques.

A. Representative images of whole hippocampal sections showing extracellular Aβ deposits, labeled with 6E10 primary antibody, and microglia labeled with Iba1 (Dapi labeled in blue, scale bar = 500μm). Enlarged panel showing microglia associated plaques (MAP; arrowheads) and non-microglia associated plaques (non-MAP; asterisks) in the subiculum (scale bar = 100μm). B. PBM appears to increase the overall deposition of extracellular Aβ plaques and average plaque size. C. Quantitative analysis shows no change in the frequency of microglia association with plaques. Microglia-associated plaques (MAP) are on average similar in size between groups, whereas non-MAP are significantly larger in 3xTg + PBM animals. (Unpaired t-test. *p < 0.05).