The Research On The Protective Effects And Mechanism Of STVNa Against NAFLD And Heart And Kidney Injure In High-fat Diet

With the rapid development of technology,Excessive intake of "three high" foods,such as high sugar,high fat and high calorie,leads to the increasing incidence of fatty liver,heart disease,chronic kidney disease and related metabolic diseases[1],seriously endangering the human health.At present,the treatment of heart,liver and kidney injury is still a lack of targeted drugs caused by high fat diet.This does not meet clinical needs.Aiming at this problem,this study mainly studied the therapeutic effect and mechanism of isostevia sodium(STVNa)on NAFLD and heart and kidney injure by high fat diet.Therefore,we selected the heart,liver and kidney injury caused by high-fat diet as the model in this study and analyzed the application value of STVNa in combating such diseases and discussed its possible mechanism.the study contents of this paper as follows:1.The models of NAFLD and cardiac and renal injury were established by using about 100 g healthy male SD rats aged 5-6 weeks sustained a high-fat diet for 10 weeks.the protective effects of STVNa on nonalcoholic fatty liver disease,myocardial injury and renal injury induced by high-fat diet in rats were studied.Results show that the content of malondialdehyde(MDA)in liver tissues was greatly increased and the activities of glutathione(GSH)and superoxide dismutase(SOD)were decreased after 1,10,20 mg/kg STVNa treated by gavage.At the same time,the results showed that STVNa of different doses could reduce the content of blood glucose triglyceride and free fatty acid to a certain extent,and promote the secretion of insulin to alleviate insulin resistance.STVNa can inhibit inflammation by decreasing the secretion of TNF-? and interleukin-6(IL-6)and pro-inflammatory factor(IL-1).it also inhibited collagen deposition by reducing the expression of TGF,collgen? and collgen?.In addition,it was found that STVNa inhibited the expression of Sirt3 and activated Sirtl,inhibited the expression of autophagy protein P62 and upregulated the expression of LC3 to promote adipose autophagy.2.The FFA-induced fatty liver injury model was established by LO2 human liver cell line,and the protective effect and molecular mechanism of STVNa on fatty liver cells in vitro were studied.We Used CCK 8 kits to test cell vitality and found that 1 mM FFA can inhibit LO2 cell vitality about 50%,in line with the requirements of cells in vitro evaluation of protection.Compared the different concentration STVNa on FFA damage LO2 cell activity,the results showed that the concentration of 1,5,10 ?M is effective in alleviating LO2 cell damage caused by fat accumulation.Another study found that STVNa can reduce the damage of mitochondrial membrane potential caused by lipid toxicity and reduce cell apoptosis.3.Since the accumulation of fat and the increase of ROS in LO2 cells are all related to adipose autophagy,Therefore,we adopted Western blot method to study the expression of autophagy-related proteins and explored the influence of STVNa on relevant autophagy signaling pathways in order to understand its action mechanism.The experimental results showed that STVNa can promote autophagy of fat by inhibiting the expression of SIRT3 and P62 and up-regulating the exprssion of sirtl and LC3.In addition,in order to further clarify whether STVNa acts on the link of "autophagy flow",we infected fatty liver cells with mRFP-GFP-LC3 double fluorescent labeled adenovirus and found that autophagy flow was blocked and autophagy lysosome was degraded in FFA-induced model group which indicated that the lack of autophagy flow led to the enhancement of autophagy activity.After STVNa intervention,the number of yellow and red spots increased significantly,indicating that STVNa can promote the smooth flow of autophagy.To sum up,STVNa enhances autophagy activity by promoting the formation stage of autophagosome to smooth the"autophagy flow" of the whole cell.4.To explore the protective effect of STVNa on myocardial damage caused by high fat and cholesterol.Firstly,the effect of STVNa on the cardiac function of rats was detected by small animal ultrasound imaging.Secondly,the changes of hfd and STVNa on the cardiac morphology of rats were analyzed from the perspective of pathology(HE).lastly,we invstigate the protective effect of STVNa possible molecular mechanisms on myocardial injury by biochemical and molecular biological methods.5.To explore STVNa kidney damage caused by high fat and cholesterol produced by the protection.The possible protective effect mechanism of STVNa was analyzed mainly from the perspective of pathology and anti-oxidation,anti-inflammatory and anti-apoptosis.Conclusion:STVNa has protective effect on NAFLD and heart and kidney injury in rats induced by high fat and high cholesterol.It also has a significant protective effect on L02 hepatocyte injury induced by FFA in vitro.The specific mechanism of STVNa in this study may be to promote metabolic fat autophagy by down-regulating Sirt3 and then up-regulating LC3B and down-regulating P62 which reduced lipid toxicity and the release of ROS,promoted cell activity,improve mitochondrial membrane potential disorder to achieve the protective effect of promoting metabolism and resisting apoptosis.