PTGDR and Alzheimer disease: Accordingly, compared with WT controls, the Tg-AD rats had 1.3-fold (t = 2.19, P = 0.02), 2.5-fold (t = 3.53, P = 0.002), and 3.2-fold (t = 3.08, P = 0.003) higher DP1 co-localization with ramified, reactive, and amoeboid microglia, respectively.