OBJECTIVETo study the effects of citalopram on the expression of proliferating cell nuclear antigen (PCNA) and proto-oncogene protein (C-fos) and cell apoptosis in frontal cortical neurons of rat after stress.

METHODSTwenty four healthy male SD rats were randomly divided into three groups (n = 8): control group, stress group (treated with saline, ig) , experimental group (treated with Citalopram 4 mg/kg x d for 28 days, ig). Rats were forced to swim to establish chronic stress model. The protein expression levels of PCNA and C-fos were tested by immunohistochemistry assay. TUNEL assay was used to test cell apoptosis. Nikon image analysis software was used to determine the number of positive cells in each index.

RESULTSCompared with the control group, the stress group showed a smaller amount of PCNA-positive cells, a larger number of C-fos positive cells, and the volume of positive cells was significantly reduced. Compared with the stress group, the PCNA positive cells were increased significantly, the C-fos positive cells and TUNEL positive cells were decreased significantly, nuclear condensation phenomenon in frontal cortical neurons and the staining was significantly lighter in experimental group (P < 0.05).

CONCLUSIONCitalopram significantly antagonize PCNA, C-fos protein expression and cell apoptosis of rat prefrontal cortical neurons caused by chronic stress, which might be the one of mechanisms of citalopram for prevention and treatment of psychosis caused by chronic stress.