Effect Of S-adenosylmethionine On Atherosclerosis In ApoE-knockout Mice

Background: Cardiovascular disease(CVD)is the leading disease that threatens human health and has risen to the top of the cause of death.Among them,atherosclerosis(AS)is a major cause of CVD.Studies have shown that S-adenosine homocysteine(SAH)is a risk indicator for the diagnosis of cardiovascular disease,and elevated plasma levels of SAH are significantly associated with high rates of cardiovascular disease.SAH is a metabolite after the methyl group is transferred by S-adenosylmethionine(SAM).As a methyl donor,SAM is converted by methionine under the action of methionine transferase,and plays an important role especially in the methylation of DNA.However,the role of SAM in the development of atherosclerosis is unknown.Objective: To investigate the effect of S-adenosylmethionine on the development of atherosclerosis in apo E knockout mice.Methods: Forty male and female apolipoprotein E gene knockout(apo E-/-)mice were randomly assigned to four groups A,B,C,and D.A high-fat diet was given to obtain food and water equally.In addition,group B(15 mg/kg),group C(30 mg/kg),group D(90 mg/kg)were intragastrically administered with S-adenosylmethionine daily,and control group A was given.An equal amount of physiological saline was administered for 8 weeks.The frozen section of the cardiac aortic valve was stained with Oil Red O to observe the degree of atherosclerosis of the aorta;the apoptosis of atherosclerotic plaque was detected by TUNEL Apoptosis Detection Kit;immunofluorescence method was used to analyze the protein quantification of SAMTOR and m TOR.Results:(1)After 8 weeks of administration,40 mice with aortic valve oil red O staining showed that apo E knockout mice showed different degrees of atherosclerosis.As the dose of S-adenosylmethionine(SAM)is increased,the severity of atherosclerosis gradually decreases.The data showed that the plaque area of atherosclerosis in groups A,B,C,and D was 62,190 ± 43,827 ?m 2,39,957 ± 15,321 ?m 2,38,019 ± 19,258 ?m 2,70,329 ± 50,2568 ?m 2.One-Way ANOVA of the data showed that the area of atherosclerosis was significantly lower in the C group(30 mg/kg)than in the control group(p < 0.05),followed by the dose of SAM.Increased,the degree of atherosclerosis has increased.The change of plaque area showed a U-shaped trend with the increase of SAM concentration.(2)The results of apoptosis detected by TUNEL kit showed that the optical density values of groups A,B,C and D were 4.02±1.46,2.52±1.15,1.81±1.01 and 9.89±1.28,respectively.Non-parametric Mann-Whitney U test results showed that the optical density of atherosclerotic plaques in group C was significantly lower than that in other groups,so group C had the least apoptosis.The change in optical density exhibited a U-shaped trend,which is consistent with the results of atherosclerosis oil red O staining.(3)Immunofluorescence experiments showed that SAMTOR and m TOR proteins were expressed at different levels in different degrees of atherosclerotic plaque.Image density analysis of immunofluorescence with Image Pro Plus revealed that the administration of SAM was increased within a certain concentration range.The concentration of the atherosclerosis was reduced,the protein expression of SAMTOR was gradually increased,and the protein expression of m TOR was gradually decreased.When the concentration exceeded a certain range,the concentration of the drug was increased again,the severity of atherosclerosis was increased,the protein expression of SAMTOR was decreased,and the protein expression of m TOR was increased,and the difference was statistically significant(p < 0.05).Conclusion: The more severe the atherosclerotic plaque,the greater the number of apoptosis.S-adenosylmethionine can inhibit the development of atherosclerosis in apo E knockout mice,and its inhibition is U-shaped.Within a certain concentration range(30mg/kg),increasing the concentration of administration can reduce the severity of atherosclerosis,and beyond a certain concentration range,it can increase the severity of atherosclerosis.The protein expression levels of SAMTOR and m TOR are associated with the development of atherosclerosis.