| Objective:Senescence is a complex life process and is one of the main causes of metabolic diseases.The dysfunction of glycolipid metabolism is closely related to the aging of liver cells.We constructed a natural aging model and conducted long-term dietary restriction interventions in middle-aged rats.The effect of aging on glucolipid metabolism and long-term dietary restrictions on aging-related glucolipid metabolism and its possible mechanism,we preliminary explored the influence of PP2 A methylation and GcK related genes in aging-related glucolipid metabolism.Methods:1.Establishment of natural aging and long-term dietary restriction model(1)Grouping : Young group(5 months),Old group(27 months),DR group(27 months with 15 months dietary restriction)(2)Rats weight was measured every 3 months.(3)HE staining was used to analysis the morphology of rat liver.2.The effect of dietary restriction on aging related glucose metabolism and its possible mechanism(1)the changes of blood glucose were detected by portable blood glucose analyzer.(2)The liver glycogen content was detected by anthrone method.(3)The expression of gluconeogenesis related mRNA was detected by qRT-PCR.3.The effect of dietary restriction on aging related lipid metabolism(1)The content of plasma lipids was detected by automatic biochemical analyzer.(2)Triglyceride in liver was extracted by isopropanol.And then,KOH and periodic acid were used to measure the content of triglyceride.(3)qRT-PCR was used to detect the expression of Hepatic fat metabolism related mRNA.4.Effects of age and dietary restrictions on the demethylation status of PP2A(1)the changes of PP2 Ac demethylation were detected by western blot.(2)real-time fluorescence quantitative PCR was used to detect mRNA expression of PP2 Ac demethylated regulatory genes LCMT1,PME and GNMT.5.Effects of age and dietary restrictions on gck-related genesThe expression of glucokinase related mRNA was detected by qRT-PCR.Results:1.Establishment of natural aging and long-term dietary restriction model(1)The body weight of rats in DR group was significantly lower than that in Old group(p<0.05).(2)Liver weight of rats in Old group and DR group were higher than that in young group(p<0.05).The liver coefficient in DR group was higher than that in young group and Old group group(p<0.05).(3)The morphology of liver tissue by HE staining: Young group and DR group was similar in the histological morphology of liver,while the hepatocyte cord disappeared,the nuclear pyknosis,the cell swelling and vacuolated degeneration were found in Old group.2.The effect of dietary restriction on aging related glucose metabolism andits possible mechanism(1)The fasting blood glucose in Old group was significantly lower than that in the young group and the DR group(p<0.05).The change of blood glucose induced by food intake in Old group was higher than that in the young group and the DR group(p<0.05).(2)The content of DR group glycogen was much higher than that of the young group and the Old group,and the difference was statistically significant(p<0.05).(3)The expression of PCK1,PCK2 and G6 pc in the Old group was significantly lower than that in the Young group.The difference was statistically significant(p<0.05).3.The effect of dietary restriction on aging related lipid metabolism(1)Compared with Young group,total cholesterol,triglyceride,low density lipoprotein and very low density lipoprotein in Old group were increased in blood plasma.The difference was statistically significant(p<0.05).(2)Compared with Young group,the content of triglyceride in liver of the diet group was higher than that of Old group,and the difference was statistically significant.However,the content of triglyceride in liver of DR group was decreased significantly,and the difference was statistically significant(p<0.05).(3)Compared with Young group,the expression of PPARa and Acot1 in Old group was significantly lower than that in young group(p<0.05).Compared with Old group,dietary restriction significantly decreased the expression of Acot1 and Acadl(p<0.05).4.Effects of age and dietary restrictions on the demethylation status of PP2ACompared with the younger group,PP2 Ac demethylation and GNMT expression levels in the older group were decreased,and the difference was statistically significant(p<0.05).Compared with the elderly group,PP2 Acdemethylation and GNMT expression levels increased in the diet restriction group(p<0.05).5.Effects of age and dietary restrictions on gck-related genesThe expression of Gck mRNA in DR group was significantly higher than that in Young group and Old group(p<0.05).Dietary restriction alleviated the decrease in aging related Gckr mRNA expression.Conclusion:1.A series of metabolic disorders of glycolipids occurred in elderly rats: the ability to regulate blood glucose decreased,the level of fasting glycogenesis decreased,the blood lipids increased,and the content of liver triglycerides increased.2.Dietary restrictions can improve fasting glycogen and high-density lipoprotein in plasma,and reduce liver triglycerides,which can protect aging related glycolipid metabolism.3.Dietary restrictions may protect aging related glycolipid metabolic disorders by regulating PP2 Ac demethylation and the expression of Gck and its related genes... |
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