Apelin-13 Ameliorates Lipopolysaccharide-induced Memory Performance Deficit Through Promotion Of Hippocampal Glucocorticoid Receptor Nucleus Translocation In Rats

[Objective] Neuroinflammation is a central role in various neurological disorders and injuries.Neuroinflammation-related diseases can impair cognition,such as neurodegeneration,brain injury,cerebral ischemia.Moreover,neuroinflammation-related cognitive impairment disorders lead to the decline of patients' life quality and bring heavy economic burden to families and society.Therefore,it is significance to explore the mechanism of neuroinflammation-related cognitive impairment.Lipopolysaccharide(LPS)can induced neuroinflammation and cause cognitive impairment in rats.Glucocorticoid receptor(GR)dysfunction plays an important role in inflammation.Study have shown that apelin-13 was involved in the regulation of cognition,and had anti-inflammatory effects in neuroinflammation,but its mechanism remains unclear.Therefore,this study investigated whether apelin-13 could ameliorates LPS-induced neuroinflammation and cognitive impairment through promotion of glucocorticoid receptor nucleus translocation in rats.[Method] The novel object recognition test and Y-maze test were performed to assess memory performance of rats.The locomotor activity was performed to assess activity of rats.The hippocampal inflammatory factor expression levels of IBA-1,GFAP,IL-1,TNF-? and IL-6 were detected by Western Blot to assess neuroinflammation of rats.The hippocampal expression levels of GR,nucleus GR and cytoplasm GR were detected by Western Blot to assess the role of glucocorticoid receptor nucleus translocation in rats.[Results] Apelin-13 restored LPS-induced decline in the discrimination index and alternation ratio in novel object recognition and Y maze.Apelin-13 had no effect on the activity of rats.Apelin-13 down-regulated LPS-induced hippocampal IBA-1,GFAP,IL-1?,TNF-? and IL-6 expression levels.Apelin-13 upregulated LPS-induced hippocampal GR expression defict,and promoted hippocampal glucocorticoid receptor nucleus translocation in rats.The GR antagonist RU486 blocked the ameliorative effect of apelin-13 on cognitive impairment in LPS-indiced rats.RU486 had no effect on the activity of rats.RU486 blocked the down-regulation effect of apelin-13 on LPS-induced hippocampal IBA-1,GFAP,IL-1?,TNF-? and IL-6 expression levels.[Conclusion] Apelin-13 ameliorates LPS-induced memory performance deficit through promotion of hippocampal glucocorticoid receptor nucleus translocation in rats.