Expression of fibroblast growth factor 9 and its receptors in the dentate gyrus of hippocampus in poststroke depression rats.

Studies have found that fibroblast growth factor 9 (FGF9) might have a negative effect in the psychiatric diseases, such as depression or anxiety, but its potential role in the pathophysiology of poststroke depression (PSD) remains uncertain. Here, we set out to investigate the expression changes of FGF9 and its receptors in PSD rats. Middle cerebral artery occlusion (MCAO) combined with chronic unpredictable mild stress was used to establish the PSD rat model. Then, the rats were randomly divided into four groups: control (sham-operation), MCAO, PSD and treated (fluoxetine injection by intraperitoneal). Weight measurement, sucrose preference test, open-field test and forced swim test were performed to evaluate the behavioral changes, and then Western blot and real-time quantitative PCR were used to detect the expression level of FGF9, fibroblast growth factor receptor 1 (FGFR1) and receptor 3 (FGFR3) in the dentate gyrus of rat hippocampus. We found that FGF9 protein and mRNA expression increased significantly in the MCAO and PSD groups; FGFR3 protein and mRNA expression decreased significantly in the MCAO and PSD groups; FGFR1 protein and mRNA expression decreased significantly in the PSD group, but increased in the treated group. Furthermore, the changes mentioned above were reversed obviously by fluoxetine. These results indicated that upregulated FGF9 expression and downregulated FGFR1 and FGFR3 expression may be involved in the pathogenesis of PSD, and the FGF9/FGFR signaling pathway may be considered as an attractive target for further study.