Single-prolonged stress induces apoptosis in the amygdala in a rat model of post-traumatic stress disorder.

OBJECTIVE To detect the apoptosis-related Bax and Bcl-2 gene expression and apoptotic cell death in the amygdala region in the single-prolonged stress (SPS) rats. METHODS A total of 100 male Wistar rats were randomly divided into a normal control group and SPS groups of 1d, 4d, 7d, and 14d. The expression of Bax and Bcl-2 was detected using immunohistochemistry and Western Blotting; TUNEL-staining and double-labeled flow cytometry (FCM) were employed for the detection and quantification of the apoptotic cells in the amygdala; morphological change of the subcellular structure in amygdala was observed by using the transmission electron microscopy (TEM). RESULTS The ratio of Bax/Bcl-2 peaked at SPS 4d and then gradually decreased. The apoptosis peaked at SPS 4d. The TUNEL-positive cells were found in each SPS group and the TUNEL-positive cells rate peaked at SPS 4d. The morphological change of amygdala cells in each SPS group bears typical apoptotic characteristics. CONCLUSIONS In the SPS rat brain, we found apoptotic process in the amygdala region which may relate to the pathogenesis of amygdala abnormal function in PTSD.