The Mannuronic oligosaccharides oligosaccharide is a kind of algin oligosaccharide, which is processed by algin and has various biological activities such as anti-oxidation, anti-inflammation and anti-tumor, and has important clinical application value. In this experiment, the model of myocardial cell senescence was established by H2O2 induction, To investigate the protective effect of Mannuronic oligosaccharides on aging cardiomyocytes.
Five groups were divided into five groups: control group (a group), H2O2 group (b group), H2O2 + Mannuronic oligosaccharide (m3k) low dose group (c group), H2O2 group + manuronic oligosaccharide (M3K) middle dose group (d group), H2O2 + manuronic oligosaccharide (M3K) high dose group (e group). When the cell fusion level was up to 50%, the cells of group b, c, d and e were induced to establish the aging model by adding 100μmol/L / l of H2O2, and the fresh DMEM was replaced after 4 h. H2O2 group continued to culture for 48 hours, Mannuronic oligosaccharide (M3K) was added to each group for 48 hours, and 50, 100mg Mannuronic oligosaccharide (M3K) was added to each group for 48 hours. The number of cardiomyocytes was detected, the expression of P21 and P53 protein in cardiomyocytes was compared, and the expression of beclin1,Atg7 and LC3- II mRNA in each group was compared. The results showed that after 48 hours of culture, the number of cells in group B (H2O2 group) was significantly lower than that in control group, and the number of cells in group C, D and E increased in a dose-dependent manner compared with group H2O2, and the number of cells in group C, group D and group E was 51.3%, 82.2% and 97.4%, respectively. Compared with the control group, the expression of P21 and P53 protein in group B (H2O2 group) increased significantly, and after 48 hours of mannose oligosaccharide (M3K) intervention, the expression of P21 and P53 protein decreased with the increase of Mannuronic oligosaccharide (M3K) concentration, and the expression ratio of P21 protein in group C, group D and group E was 20.0%, 29.3% and 40.3% lower than that in group b, respectively, and the expression of p21 protein in group C, D and E was 20.0%, 29.3% and 40.3%, respectively. The P53 protein ratio decreased by 30.2%,51.2%, and 62.2%, respectively, compared with group B. compared with the control group, the expression levels of beclin1, Atg7 and LC3- II mRNA of H2O2 group decreased significantly. After 48 hours of Mannuronic oligosaccharide (M3K) intervention, the expression of beclin1, Atg7 and LC3- II mRNA in cardiomyocytes of each group increased in a concentration-dependent manner. The expression of beclin1 in group C, group D and group E was 35.9%, 78.0%, 132.6% and 96.4%, respectively, which was 18.7%, 45.3% and 90.4% higher than that in group b, respectively. the expression of mrna in group C, D and group E increased by 62.6%, 96.4% and 18.7%, 45.3% and 90.4%, respectively. compared with group b, the expression of mRNA in group C, group D and group E increased by 35.9%, 73.0% and 90.4%, respectively.
The results showed that H2O2 induced intracellular oxidative stress and cell senescence, which showed cell cycle arrest and decreased proliferation. Mannuronic oligosaccharide (m3k) could down-regulate the expression of p21 and p53 protein in aging cells for 48 hours, alleviate the cell cycle arrest, accelerate the proliferation of aging cardiomyocytes, and thus delay the senescence of cardiomyocytes. After treatment with Mannuronic oligosaccharide (m3k), the expression of autophagy related genes beclin1, Atg7 and LC3- II mRNA increased, indicating that Mannuronic oligosaccharide (m3k) may be related to autophagy activation.