Objective To investigate the effects of leptin on hypothalamic neuron activity and lipid metabolism in adipose tissue of obese mice.Methods 10 leptin-deficient obese(ob/ob)mice with homozygous mutation of leptin gene and 10 wild-type(WT)mice born in the same litter were randomly divided into control group and leptin treatment group.The activity of pro-opiomelanocortin(POMC)neurons and tyrosine hydroxylase(TH+)neurons,the morphological changes of adipose tissue and the expression of lipid-related genes were analyzed by immunofluorescent staining,HE staining and Real-time PCR.Results Compared with the WT mice,the ob/ob mice showed decreased activity of POMC neurons and TH+neurons and larger cell diameter in adipose tissue and liver tissue.In addition,the expressions of heat-related genes uncoupling protein 1(UCP1),cytochrome c oxidase subunit 8B(Cox8b)and cell death-inducing DNA fragmentation factor,alpha subunit-like effector A(Cidea)in subcutaneous white fat in ob/ob mice decreased significantly,and the expressions of lipid synthesis-related genes sterol regulatory element binding transcription factor 1(Srebp1)and fatty acid synthase(Fas)increased significantly.After treated with leptin,the activities of POMC and TH+neurons were increased,and the cellular diameter and the degree of vacuolar degeneration were reduced in the adipose tissue and liver.Further analyses showed that the expressions of thermogenesis-related genes and lipolysis-related genes were increased,but expressions of lipid synthesis-related genes were reduced in brown adipose tissue.Conclusion Leptin treatment could prevent the increasing of obesity in ob/ob mice,which is associated with increased lipolysis and reduced lipid synthesis through activation of hypothalamic POMC neurons and peripheral adipose tissue sympathetic nervous system.
维普
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