Effect of extracellular vesicles derived from adipose on hippocampal neuronal damage in mice with a high-fat diet / 中国药理学通报

ABSTRACT

Aim To investigate the effect of extracellular vesicles secreted by adipose tissue of mice on hippocampal neurons and cognitive behavior of mice with a high-fat diet.Methods Twenty C57BL/6J male mice were randomly divided into normal diet(ND)group(n=10)and high-fat diet(HFD)group(n=10), fed for 28 weeks.The weight of mice was recorded weekly.The level of fasting blood glucose, insulin and the insulin resistance index(HOMA-IR)of mice were tested at week 27.At week 28, the learning and memory abilities of mice were assessed by the Morris water maze.The morphological differences in adipose tissue were observed by HE staining, and the extracellular vesicles secreted from adipose tissue were quantified by TEM and NTA.Extracellular vesicles derived from adipose tissue labeled with PKH 67 were injected into normal mice via the tail vein, and after 30 h, the uptake of extracellular vesicles was detected in the hippocampal slice.The primary hippocampal neurons were treated with extracellular vesicles with the same amount of protein, and the effects of them on neuronal morphology and cell viability were observed.Results Compared with ND group, mice in HFD group were significantly heavier, with hyperglycemia, hyperinsulinemia and higher insulin resistance index.In the Morris water maze test, the HFD group showed a longer escape latency and less swimming time in the target zone.The volume of adipocytes and the amount of extracellular vesicles secreted from them significantly increased in HFD group.Extracellular vesicles secreted by adipose tissue could be internalized by both the primary hippocampal neurons and the hippocampal neurons in the normal mice.Compared with ND group, extracellular vesicles secreted by adipose tissue of the HFD group significantly reduced the length of primary hippocampal neuronal dendrites, the number of primary and secondary dendrites, and the cell viability of neuron cells.Conclusion Long-term high-fat diet could damage the hippocampal neurons by affecting the extracellular vesicles derived from adipose tissue.