Effect of Lactobacillus casei on the depressive behavior and the expression of NR1 and NR2A recep-tors in hippocampus of rats with postpartum depression induced by maternal separation / 中华行为医学与脑科学杂志

ABSTRACT

Objective To investigate the effect of Lactobacillus casei on depressive behavior and the expression of NR1, NR2A receptor in postpartum depression rats induced by maternal separation. Methods Twenty-four Sprague-Dawley female rats were randomly divided into control group( CON group) (n=8),postpartum depression group(PPD group) (n=8),postpartum depression with lactobacillus casei group(PPD+ Lactobacillus casei group) (n=8). Rats of the control group were given no interventions. Rats in PPD group and PPD+Lactobacillus casei group were given maternal separation to establish depression model. And then the rats in PPD+Lactobacillus casei group were treated with Lactobacillus casei ( 8× 108CFU/(kg·d)) for 4 weeks after 14 days of maternal separation. The forced swimming test ( FST) was employed to detect the depressive behaviors. Lactobacillus,Bifidobacterium,Enterococcus faecalis and Esche-richia coli in cecum of rats and the expression of NR1 and NR2A mRNA in hippocampus of rats were detec-ted by real-time fluorescence quantitative PCR. Results Compared with CON group ((157. 50±8. 13) s), the immobility time of PPD group((200. 00±10. 35) s) was significantly longer (t=-3. 23,P<0. 05). Com-pared with PPD group,the immobility time of PPD+ Lactobacillus casei group ((153. 25±7. 41) s) was sig-nificantly shortened (t=3. 67,P<0. 05),and the depressive behavior was improved. Compared with CON group,the mRNA expression of Lactobacillus ((1. 47± 0. 08),t=-5. 87,P<0. 01),Enterococcus faecalis ((1. 23±0. 08),t=-2. 85,P<0. 05) and Escherichia coli( (1. 33±0. 07),t=-4. 96,P<0. 01) in caecum were significantly increased in PPD group, while that of Bifidobacterium decreased significantly (( 0. 65 ± 0. 07),t=5. 18,P<0. 01). Compared with PPD group,the mRNA expression of Lactobacillus ( ( 1. 05 ± 0. 05),t=3. 67,P<0. 01),Enterococcus faecalis ((0. 97±0. 05),t=2. 74,P<0. 05) and Escherichia coli ((1. 06±0. 05),t=3. 31,P<0. 01) were significantly decreased in PPD+ Lactobacillus casei group,while that of Bifidobacterium increased significantly ((0. 98± 0. 04),t=-4. 26,P<0. 01). Compared with CON group,the mRNA expression of NR1 receptor (( 0. 57 ± 0. 04), t=9. 65, P<0. 01) and NR2A receptor ((0. 60±0. 05),t=8. 64,P<0. 05) in hippocampus of rats in PPD group were significantly decreased. Com-pared with PPD group,the expression of NR1 receptor ((1. 01±0. 05),t=-5. 39,P<0. 01) and NR2A re-ceptor ((0. 98±0. 07),t=-3. 91,P<0. 05) in hippocampus were increased significantly in PPD+ Lactoba-cillus casei group. Conclusion Lactobacillus casei can improve the depressive behavior of postpartum depression in rats,and improve the intestinal flora,which affect the expression of NR1 and NR2A in hippocampus.