Effects of Chaihu-Shugan San on behavior and hippocampal neurogenesis in depression model mice / 中华行为医学与脑科学杂志

ABSTRACT

Objective:To explore the effects of Chaihu-Shugan San (CSS) on the behavior and neurogenesis function of depression model mice induced by chronic unpredictable mild stress (CUMS).Methods:Thirty clean grade healthy male C57BL/6 adult mice were randomly divided into control group (Con group), model group (CUMS group) and Chaihu-Shugan San treatment group (CSS group), with 10 mice in each group.The mice in CUMS group and CSS group were given CUMS intervention to establish depression model. At the same time of modeling, the mice in CUMS group and CSS group were given distilled water and CSS(2.7 g/kg) by gavage respectively.While the mice in Con group were only given equal volume distilled water by gavage without CUMS stimulation.After the intervention, the depressive-like behavior of mice was evaluated by increased body weight, sugar water preference test (SPT), forced swimming test (FST) and tail suspension test (TST). The number of newborn neurons was detected by immunofluorescence staining. The mRNA expression levels of brain-derived neurotrophic factor (BDNF), fibroblast growth factor 2 (FGF2) and spindle and kinetochore-associated protein 2(SKA2) in mice hippocampus were detected by qRT-PCR.Statistical analysis was performed by SPSS 22.0 software. One-way ANOVA was used for multi group comparison, and Tukey test was used for pairwise comparison.Results:(1) After modeling, there was significant difference in body weight increment among the three groups ( F=8.859, P <0.05). The body weight increment of CUMS group was lower than those of Con group and CSS group (both P< 0.05). There were significant differences in sugar water preference rate, tail suspension immobility time and swimming immobility time among the three groups ( F=10.544, 12.957, 8.095, all P<0.05). The sugar water preference rate in CUMS group was lower than that in Con group ((87.46±2.78)%, (93.90±3.31)%, P<0.05), and that in CSS group was higher than that in CUMS group ((91.65±2.61)%)( P<0.05). The tail suspension immobility time ((198.00±27.57) s) and swimming immobility time ((322.20±46.98) s) in CUMS group were higher than those in Con group ((138.80±38.50) s, (238.50±50.51) s, both P<0.05). The tail suspension immobility time ((139.00±21.29) s) and swimming immobility time ((265.20±44.90) s) in CSS group were lower than those in CUMS group (both P<0.05). (2) Immunofluorescence showed that there was significant difference in the number of newborn neurons labeled by BrdU and NeuN in the dentate gyrus of hippocampus among the three groups ( F=9.486, P<0.05). The number of double labeled cells (31.66±3.21) in CUMS group was lower than that in Con group(63.66±15.17) and CSS group (58.00±6.00) (both P<0.05). (3) RT-PCR results showed that the mRNA levels of BDNF, FGF2, SKA2 in hippocampal dentate gyrus of the three group were significantly different( F=14.522, 9.337, 8.701, all P<0.05). The levels of BDNF mRNA (0.79±0.06), FGF2 mRNA (0.74±0.18) and SKA2 mRNA (0.52±0.32) in the dentate gyrus of hippocampus in CUMS group were lower than those in Con group (BDNF mRNA (1.03±0.10), FGF2 mRNA (1.04±0.11), SKA2 mRNA (1.05±0.37), all P<0.05). Compared with CUMS group, the mRNA levels of BDNF (1.07±0.80), FGF2 (1.30±0.29) and SKA2 (1.40±0.55) in CSS group were higher (all P<0.05). Conclusion:CSS can alleviate the depressive like behavior of depression model mice, which may be related with increasing the mRNA expression levels of BDNF, FGF2, SKA2 and promoting the proliferation of neural stem cells in hippocampus.