Relevance Of A-MSH-PKA-BDNF And Energy Metabolism In Mice With MSG-induced Obesity

ObjectivesThe first, to observe the expression of brain-derived neurotrophic factor (BDNF) in hypothalamic and adipose tissue in mice with monosodium glutamate (MSG)-induced obesity. The second,to observe the expression of BDNF in adipose tissue and in skeletal muscle tissue in mice with monosodium glutamate (MSG)-induced obesity and after injection with a-MSH. The last, to observe the expression of BDNF in astrocytes with administration of a-MSH and H89.MethodsIn animal experiments,The effects of hypothalamic lesions,specifically arcuate nucleus (ARC) lesions, induced by MSG injection were studied in male mice at the neonatal stage. The following parameters were compared in mice .at the 8-week-old and at the 12-week-old : body weight, body length, Lee’s index, food intake, body temperature, fat weight, and levels of total cholesterol (CHOL), triglyceride (TG),low-density lipoprotein (LDL), high-density lipoprotein (HDL) and blood glucose(GLU). At the 8-week-old, wherein a portion of mice, the BDNF expression levels in hypothalamic and adipose tissue were measured using western blotting. At the 12-week-old, The BDNF expression levels in adipose tissue and skeletal muscle tissue were measured using western blotting after intracerebroventricular administration of a-MSH.In cell experiments, astrocytes were prepared from mice cerebral tissue of 1- to 2-day-old postnatal mice pups as described previously. The BDNF expression levels in astrocytes was measured using western blotting after administration of a-MSH and the PKA inhibitor H89.ResultsIn the first part of the experiment,compared with the control group, the model group body had significantly higher weight, Lee’s index, food intake, fat weight, CHOL, TG,LDL, HDL, and GLU levels. BDNF expression levels in hypothalamic and adipose tissue were markedly down-regulated in the model group.In the second part of the experiment, F-NC group compared with the N-NC group,the model group body had significantly higher Lee’s index, fat weight, CHOL,TG,LDL,GLU levels and BDNF expression levels in skeletal muscle tissue . In addition,lower food intake ,body length and BDNF expression levels in adipose tissue were observed in F-NC group . F-A group compared with the F-NC group, lower food intake ,down-regulated BDNF expression levels in adipose tissue and up-regulated BDNF expression levels in skeletal muscle tissue were observed in F-A group, the other detection did not significant differences. After administration of a-MSH and the PKA inhibitor H89. The down-regulated BDNF expression levels in astrocytes was observed.DiscussionBDNF was closely associated with MSG-induced hypothalamic obesity.In addition,a-MSH-PKA-BDNF this pathway was involved in regulating energy metabolism in mice with Monosodium glutamate - induced obesity...