The proliferation of microglia in the emotional disorders-related brain regions of rats with post-stroke depression

Abstract

Objective To explore the proliferation of microglia in the frontal cortex, hippocampus and amygdala of the post-stroke depression (PSD) in rats.To understand the role of microglia in the pathogenesis of PSD. Methods The adult female SD rats were divided into four groups( n=5 per group): normal control group, depression group, stroke group and PSD group.In the depression group, the depression model rat were established by chronic unpredictable mild stress(CUMS)combined with separately breeding.In the stroke group, focal cerebral ischemic rat models were established with thread embolization method.In the PSD group, focal cerebral ischemic models rat were established with thread embolization method firstly, and then PSD models rat were established with comprehensive chronic unpredictable mild stress(CUMS)and separately breeding on this basis.After the procedure, rats were subjected to sucrose preference test and open field test.At the postoperative eighth weekend, immunofluorescence technology was used to detect the proliferation changes of OX42 positive cells in the frontal lobe, hippocampus and amygdale. Results At the 29th day after CUMS, the sucrose solution consumption ((23.8±0.8)%), horizontal movement distance of open field test((63.0±1.2)cm) and vertical movement distance((25.0±1.0)cm) in PSD group were significantly lower than those in normal group((31.2±1.9)%; ( 69.8±2.3)cm; (31.0±1.6)cm) and depression group((31.0±1.4)%; (70.2±2.4)cm; (30.8±1.1)cm) (P<0.05). The number of OX42 positive cells of frontal lobe, hippocampus and amygdale in PSD group((20.8±2.6); (20.2±1.3); (19.8±2.6))increased significantly compared with those of normal group((7.4±2.3); (8.0±1.6); (9.4±2.1)), depression group((8.0±2.0); (7.8±2.2); (9.2±1.9))and stroke group((9.6±1.1); (9.4±2.2); (10.2±2.6))(all P<0.05). Conclusion The number of microglia in PSD group in the emotional disorders related brain areas(the frontal lobe, hippocampus and amygdale) increases obviously and the increased expression of microglia in the emotional disorders related brain areas may be responsible for the pathogenesis of PSD. Key words: Post-stroke depression; Microglia; Frontal lobe; Hippocampus; Amygdala