Effects of fluoxetine on mast cell morphology and protease-1 expression in gastric antrum in a rat model of depression.

AIM: To investigate the effects of fluoxetine on depression-induced changes of mast cell morphology and protease-1 (rMCP-1) expression in rats.

METHODS

A Sprague-Dawley rat model of chronic stress-induced depression was established. Fifty experimental rats were randomly divided into the following groups: normal control group, fluoxetine+normal control group, depressed model group, saline+depressed model group, and fluoxetine+depressed model group. Laser scanning confocal microscopy (LSCM) immunofluorecence and RT-PCR techniques were used to investigate rMCP-1 expression in gastric antrum. Mast cell morphology was observed under transmission electron microscopy. ANOVA was used for statistical analysis among groups.

RESULTS

Morphologic observation indicated that depression induced mast cell proliferation, activation, and granule hyperplasia. Compared with the normal control group, the average immunofluorescence intensity of gastric antrum rMCP-1 significantly increased in depressed model group (37.4+/-7.7 vs 24.5+/-5.6, P<0.01) or saline+depressed model group (39.9+/-5.0 vs 24.5+/-5.6, P<0.01), while there was no significant difference between fluoxetine + normal control group (23.1+/-3.4) or fluoxetine+depressed model group (26.1+/-3.6) and normal control group. The average level of rMCP-1mRNA of gastric antrum significantly increased in depressed model group (0.759+/-0.357 vs 0.476+/-0.029, P<0.01) or saline+depressed model group (0.781+/-0.451 vs 0.476+/-0.029, P<0.01), while no significant difference was found between fluoxetine+normal control group (0.460+/-0.027) or fluoxetine+depressed model group (0.488+/-0.030) and normal control group. Fluoxetine showed partial inhibitive effects on mast cell ultrastructural alterations and de-regulated rMCP-1 expression in gastric antrum of the depressed rat model.

CONCLUSION

Chronic stress can induce mast cell proliferation, activation, and granule hyperplasia in gastric antrum. Fluoxetine counteracts such changes in the depressed rat model.