Effects of fluoxetine on lipidomics of hippocampal tissue in chronic unpredictable stress model rats / 中华行为医学与脑科学杂志

ABSTRACT

Objective:To investigate the effects of fluoxetine (Flx) on lipidomics of hippocampal tissue in chronic unpredictable stress (CUS) model rats.Methods:A total of 30 Sprague-Dawley rats were randomly divided into Sham group, CUS group and CUS+ Flx group, with 10 rats in each group. Rats in the CUS group and CUS+ Flx group were received one or two random stimuli every day for 28 days, and then they were received intraperitoneal injection of normal saline(1 ml/kg) and fluoxetine(10 mg/kg) respectively once a day for 14 days. Rats in the Sham group were maintained in their home cages for 28 days, and then received intraperitoneal injection of saline (1 ml/kg) once a day for 14 days. The sugar water preference experiment was carried out 24 hours after the last injection, and then the rats were killed to separate the rat hippocampus. The levels of lipid composition in hippocampus were detected by high performance liquid chromatography-mass spectrometry. The relative content of lipid was analyzed by Simca-p 14.1 and LipidSearch software version 4.1. SPSS 19.0 was used for statistical analysis. One-way ANOVA or Kruskal-Wallis test was used for comparison among groups, and Bonferroni test was used for post-hoc test. Pearson correlation or Spearman correlation was used to analyze the correlation between behavioral indexes and lipid molecular level in hippocampus.Results:There was significant difference in sugar preference test among the three groups ( F=12.830, P<0.001). The percentage of sucrose intake of rats in CUS group ((43.57±12.38)%) was significantly lower than those in Sham group ((67.09±11.81)%) and CUS+ Flx group ((62.74±8.58)%) (both P<0.05). Ninety five differential lipid molecules were screened among the three groups by lipidomic analysis, mainly distributed in glycerophospholipids and sphingolipids. Among them, levels of PE (34∶1e)+ H( r=-0.477), PE(18∶1p/20∶1)+ H( r=-0.433), PE(18∶1/18∶1)+ Na( r=-0.603), PE(36∶2p)-H( r=-0.382), PE(16∶0/20∶4)-H( r=-0.464), PE(18∶0/18.2)-H( r=-0.482), PE(16∶0e/22∶6)-H( r=-0.514), PE(18∶1/20∶4)-H( r=-0.511) and CerG1 (d18∶2/24∶0+ O)+ H( r=-0.490) were negatively correlated with sucrose preference rate (all P<0.05), whereas levels of PE (42∶6p)+ Na( r=0.379), PE(34∶0p)-H( r=0.397) and SM (d22∶1/16.0)+ HCOO( r=0.388) were positively correlated with sucrose preference rate (all P<0.05). Conclusion:Flx improves the depressive-like behavior of CUS model rats, which may be related to the regulation of hippocampal glycerophospholipid and sphingolipid metabolism.