ObjectiveExploring the role of microRNA126 （miRNA126） in chronic kidney disease combined with atherosclerosis （CKD AS） by regulating the phosphatidylinositol-3-kinase （PI3K）/protein kinase B （Akt）/mammalian target of rapamycin （mTOR） signaling pathway and the mechanism of Shenshuai Xiezhuo decoction in the intervention of CKD AS rats with 5/6 nephrectomy combined with high-fat feeding. MethodA total of 60 SD rats were randomly divided into sham operation group， model group， losartan group， and low， medium， and high dose groups of Shenshuai Xiezhuo decoction. The CKD AS rat model was established by 5/6 nephrectomy combined with high-fat feeding for 10 weeks. The low， medium， and high dose groups （6.0， 12.0， 24.0 g·kg^-1·d^-1） of Shenshuai Xiezhuo decoction and the losartan group （20 mg·kg^-1·d^-1） were gavaged， and the corresponding intervention was carried out for eight weeks. Then， the rats were killed， and samples were collected for corresponding detection. Fully automated biochemical analyzers were used to detect kidney function and blood lipids in rats： blood creatinine （SCr）， blood urea nitrogen （BUN）， total cholesterol （TC）， triglyceride （TG）， and low-density lipoprotein cholesterol （LDL-C） levels. Hematoxylin-eosin （HE） and Masson staining of aortic tissue and pathological observation under a light microscope were carried out， and autophagosomes and autophagy lysosomes were observed by transmission electron microscopy. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was used to determine the mRNA levels of miRNA126， PI3K， Akt， and mTOR in rats， and Western blot was used to determine the protein expression levels of phosphorylated （p）-PI3K， PI3K， p-Akt， Akt， p -mTOR， mTOR， benzyl chloride 1 （Beclin-1）， and microtubule-associated protein light chain 3Ⅱ/Ⅰ （LC3Ⅱ/LC3Ⅰ）. ResultCompared with the sham operation group， the serum SCr， BUN， TC， TG， and LDL-C in the model group were significantly increased （P<0.01）. Compared with the model group， the SCr， BUN， TC， TG， and LDL-C were decreased in the losartan group and low， medium， and high dose groups of Shenshuai Xiezhuo decoction （P<0.05）. Compared with the sham operation group， thickening plaques， infiltration of mononuclear macrophages， a small number of foam cells， disordered arrangement of smooth muscle fibers in the tunica media， and increased collagen fibers were observed in the model group， and the lesions in the losartan group and Shenshuai Xiezhuo decoction groups were alleviated compared with those in the model group. Compared with the model group， the number of autophagosomes and autophagy lysosomes increased in the medium and high dose groups of Shenshuai Xiezhuo decoction. Compared with the sham operation group， the expression of miRNA126 in the aortic tissue of the model group was significantly decreased （P<0.01）， and the mRNA expressions of PI3K， Akt， and mTOR were significantly increased （P<0.01）. Compared with the model group， the expression of miRNA126 in the aortic tissue of rats in high， medium， and low dose groups of Shenshuai Xiezhuo decoction and losartan group was significantly increased （P<0.01）， while the mRNA expressions of PI3K， Akt， and mTOR were significantly decreased （P<0.01）. Compared with the sham operation group， the protein expressions of p-PI3K， PI3K， p-Akt， Akt， p-mTOR， and mTOR in the model group were significantly increased （P<0.01）， while the protein levels of Beclin-1， LC3Ⅰ， and LC3Ⅱ were significantly decreased （P<0.01）. Compared with the model group， the protein expressions of p-PI3K， PI3K， p-Akt， Akt， p-mTOR， and mTOR in the losartan group and low， medium， and high dose groups of Shenshuai Xiezhuo decoction were decreased （P<0.05）， while the protein levels of Beclin-1 and LC3Ⅱ/LC3Ⅰ were increased （P<0.05）. ConclusionThe expression of miRNA126 is decreased in the aortic tissue of CKD AS rats， and the PI3K/Akt/mTOR pathway is activated to inhibit autophagy flux. Shenshuai Xiezhuo decoction regulates the PI3K/Akt/mTOR signaling pathway through miRNA126， restores the autophagy of aortic endothelial cells， protects the damage of CKD vessels， reduces the formation of As plaques， and slows the development of cardiovascular complications.