青年和老年小鼠脑糖原及其代谢的差异

目的:比较青年小鼠和老年小鼠不同脑区糖原及其代谢的差异,为后续相关研究奠定基础。方法:分别取雄性C57BL/6J青年小鼠(8周龄)和老年小鼠(18月龄)皮层、海马、纹状体三个脑区脑组织,通过糖原定量试剂盒检测糖原含量,通过Western Blot检测糖原代谢相关酶(包括糖原合成、糖原分解、葡萄糖转运、乳酸转运相关酶类)的表达水平。结果:与青年小鼠相比,老年小鼠皮层、纹状体糖原含量明显上升,但海马的糖原含量无明显变化。在糖原合成代谢的关键酶中,糖原合成酶在老年小鼠皮层、纹状体的表达水平明显升高,而海马区则无明显差异;糖原分支酶在老年小鼠皮层的表达水平有所下降,在海马和纹状体则无明显变化。在糖原分解代谢的关键酶中,老年小鼠的糖原磷酸化酶在皮层、海马和纹状体均明显升高,而糖原脱支酶在上述脑区则无明显变化。葡萄糖转运体1的表达水平在老年小鼠与青年小鼠各脑区无显著差异。在单羧酸转运体中,老年小鼠单羧酸转运体1在各脑区均明显上升,单羧酸转运体4在皮层明显升高,其余脑区则无明显差异。结论:老年小鼠脑内糖原含量总体上较青年小鼠高,老年小鼠脑糖原代谢通路相关酶的表达与青年小鼠存在明显差异,且不同脑区之间存在异质性。

Differences of Brain Glycogen and Its Metabolism between Young and Old Mice

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 was 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 was 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 was 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 were obviously increased, but there were no significant differences in other brain regions. Conclusion: Generally, brain glycogen levels in old mice were higher than that in young mice. The expressions 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.