| ABSTRACT Objective: To compare the differences of glycogen metabolism in different brain regions between young mice and old mice, and lay the foundation for further studies. Methods: The tissues of cortex, hippocampus and striatum of male C57BL/6J young mice (8 weeks old) and old mice (18 months old) were separately collected. The glycogen levels in these tissues were analyzed with a glycogen assay kit. Western blot was used to detect the expression levels of glycogen metabolism related enzymes. Results: Compared to young mice, glycogen levels in the cortex and striatum in old mice were significantly increased, but glycogen level in the hippocampus showed no significant change. Among key enzymes of glycogenesis, the expression of glycogen synthase 1 (GYS1) in the cortex and striatum in old mice were obviously increased, but it didn’t show obvious difference in the hippocampus; the expression of glycogen branch enzyme 1 (GBE1) in the cortex was decreased, however, there were no significant changes in the hippocampus and striatum. Among key enzymes of glycogenolysis, the expression of glycogen phosphorylase, brain form (PYGB) in the cortex, hippocampus and striatum were increased, but there were no significant differences in the expression of glycogen debranch enzyme (AGL) in these regions. The expression of glucose transporter 1 in these regions were not significantly changed between young mice and old mice. In addition, among monocarboxylic acid transporters, the levels of monocarboxylic acid transporter 1 (MCT1) in these brain regions in old mice were significantly increased. The levels of monocarboxylic acid transporter 4 (MCT4) in the cortex was obviously increased, but there were no significant differences in other brain regions. Conclusions: Generally, brain glycogen levels in old mice were higher than that in young mice. The expression of enzymes in the pathway of brain glycogen metabolism in old mice were significantly different from that in young mice, and the glycogen metabolism differences were highly heterogeneous among various brain regions. |
