Fig.4.

Markers of neuroinflammatory microglia activation is present in the cortex of 12-month-old NCCR mice. A) 12-month-old NCCR mice show clusters of activated microglia compared to TRE-SV40T controls. Iba1-labeled microglia show CD45 co-labeling (arrows). There are also CD45^pos/Iba-1^neg cells, indicative of brain leukocyte infiltration (arrowheads). Iba-1 labeled microglia also show co-labeling with CD68 (arrows), and MHCII (arrows). Age-matched control brain sections from TRE-SV40T Tg mice littermates (TAg control) that were maintained on the same diet regimen did not show CD45, CD68, or MHCII labeling. B) Confocal imaging shows p16 labeling in a subset of microglia (arrows). The p16 co-labeled microglia also show blebbing, a morphological feature associated with senescent microglia (arrows). Age-matched control brain sections from TRE-SV40T Tg mice littermates (TAg control) that were maintained on the same diet regimen did not showp16 labeling (data not shown). C) Image J software was used to quantify the percent of area covered by MHCII immunofluorescence. MHCII-positive areas were increased by 770% in the NCCR mice compared to TAg control mice at 12 months of age (unpaired t-test with Welch’s correction for unequal variances, p = 0.033). n = 2 animals per group, with 2 sections per animal and 20 individual regions of interest evaluated per brain section, as shown in Fig. 3A.