Abstract: Objective To detect the expression of signal transducer and activator of transcription 3 (STAT3) and P-STAT3 in the
brain of the APPswe/PS △E9 double transgenic mouse model of Alzhaimer’s disease (AD) and invesitgate their possible role in
AD. Methods APPswe/PS △E9 double transgenic mice and control mice were examined for cerebral STAT3 and P-STAT3
expressions using immunothistochemistry. Results STAT3 and P-STAT3 were expressed in the different regions of mouse
brain. In the transgenic mice and the control mice, the positivity rates of STAT3 were 93.75% and 87.50% in the cerebral cortex,
87.50% and 43.75% in the basal forebrain, 81.25% and 37.50% in the hippocampus, and 62.50% and 0.00% in the cerebellum,
respectively, showing significant differences between the mice in the STAT3 expressions in the basal forebrain, hippocampus
and cerebellum (P<0.05). The positivity rates of P-STAT3 in the two groups were 0.00% and 0.00% in the cerebral cortex, 68.75%
and 0.00% in the basal forebrain, 62.50% and 12.50% in the hippocampus, and 43.75% and 0.00% in the cerebellum,
respectively, showing also significant differences in the basal forebrain, hippocampus and cerebellum (P<0.05). The expression
of STAT3 was positively correlated with that of P-STAT3 in transgenic AD mice (P<0.05). Conclusion STAT3 and P-STAT3 are
highly expressed in the basal forebrain, hippocampus and cerebellum in transgenic AD mice and may participate in the
pathological process of AD.