The Protective Of Alginate Oligosaccharide On The D-galactose Induced Cardiac Aging Mice

Objective:To investigate the protective effects and mechanisms of alginate oligosaccharide?AOS?on the D-galactose?D-gal?induced cardiac aging mice.Methods:Forty five eight-week-old C57BL/6 male mice were randomly divided into five groups?n=9/group?:Control group?Control?,Model group?D-gal?,Alginate oligosaccharide low-dose group?AOS?L??,Alginate oligosaccharide middle-dose group?AOS?M??,Alginate oligosaccharide high-dose group?AOS?H??.Mice in Control group were treated with sterile water for injection(5ml·kg^-1·d^-1)by subcutaneous injection for eight weeks.At the same time,mice in other group were treated with D-gal(150mg·kg^-1·d^-1)by subcutaneous injection for eight weeks.When the D-galactose was injected at the fifth week,the groups?AOS?L?,AOS?M?,AOS?H??were respectively given alginate oligosaccharide?50mg/kg,100mg/kg and 150mg/kg?via gavage daily for 4 weeks.And the control group and model group were treated with distilled water?10ml/kg?via gavage daily for 4 weeks.At the end of the experiment,the cardiac function of mice were evaluated with small animal ultrasound,and the pathologic changes of myocardium were examined by HE staining.The activation of AMPK,NF-?B and p38MAPK signal pathway and the aging associated protein SIRT1,p53 in the myocardial tissue of mice were detected using Western Blot.RT-PCR were used to detect IL-6,TNF-?mRNA expression,and the concentration of pro-inflammatory cytokines IL-6,TNF-?in serum was detected using ELISA.Results:1.The mice of Control group left ventricular ejection fraction and left ventricular fractional shortening were normal.The mice of Model group left ventricular ejection fraction and left ventricular fractional shortening decreased,compared with the control group,the difference was statistically significant?P<0.05?.With the higher dose of AOS in the group,the left ventricular ejection fraction and left ventricular fractional shortening were significantly increased,compared with the model group,the difference was statistically significant?P<0.05?.2.The mice of myocardial structure and cell morphology was normal size with HE staining in the control group.The disorder of cell arrangement,the wider of cardiomyocytes space and the bigger of cardiomyocytes was observed in the model group,showing the characteristics of senescence.The myocardial tissue injury was significantly improved,and the normal cardiomyocytes size and arrangement was observed in mice of AOS intervention group.3.Western Blot analysis showed that SIRT1 expression was decreased and the expression of p53 was significantly increased in myocardial tissue of model group mice,compared with the control group,there was significant difference?P<0.05?.The expression of SIRT1 increased with the dose of AOS increased,whereas the expression of p53decreased with the dose of AOS increased,compared with the model group,there was significant difference?P<0.05?.4.Western Blot analysis showed that the expression of I?B?and p-AMPK decreased,and the expression of p-I?B?and p-p38MAPK protein increased,compared with the control group in myocardial tissue of model group mice,the difference was statistically significant?P<0.05?.The expression of I?B?and p-AMPK increased with the dose of AOS increased,whereas the expression of p-I?B?and p-p38MAPK decreased with the dose of AOS increased,compared with the model group,the difference was statistically significant?P<0.05?.5.Western Blot analysis showed that the expression of NF-?B p65 decreased in the cytoplasm of myocardial tissue,at the same time,the expression of NF-?B p65 increased in myocardial tissue of model mice in the cell nucleus,compared with the control group,the difference was statistically significant?P<0.05?.The expression of NF-?B p65increased the mice myocardium cytoplasm,and the expression of NF-?B p65 decreased the mice myocardium cell nuclear with the dose of AOS increased,compared with model group,the difference was statistically significant?P<0.05?.6.RT-PCR results showed that the pro-inflammatory cytokines gene expression of IL-6,TNF-?increased in Model group,compared with the control group?P<0.05?.Compared with the model group,the pro-inflammatory cytokines gene expression of IL-6,TNF-?decreased with the dose of AOS increased?P<0.05?.7.The results of ELISA test showed that compared with the control group,the pro-inflammatory cytokines IL-6 and TNF-?were increased in the plasma of model group?P<0.05?.However,compared with the model group,the pro-inflammatory cytokines IL-6 and TNF-?in the plasma of the AOS were significantly reduced?P<0.05?,and the higher AOS dose,the lower the content.Conclusions:AOS attenuates D-galactose-induced cardiac aging,it may involve in inhibiting AMPK/SIRT1/NF-?B signaling pathway.