Moxibustion at "Zusanli"(ST36) mitigates senescence in subacute aging rats via regulating SIRT1/p53 signaling pathway

Abstract

To observe the effect of moxibustion at "Zusanli"(ST36) on the silent information regulator 1 (SIRT1) /p53 signaling pathway in subacute aging model rats, so as to reveal its mechanisms in delaying aortic aging. Male SD rats were divided into blank group, model group, prevention group and treatment group, with 20 rats in each group. Subacute aging model was established by intraperitoneal injection of D-galactose(500 mg·kg-1·d-1). In the morning, rats in the prevention group received moxibustion at ST36 with 3 moxa cones after modeling operation, once every day for 42 d. From the day after the 42-day modeling, rats in the treatment group received the same moxibustion treatment as the prevent group for 28 d. Rats in the blank and model group were fixed in the similar way as the other two groups, for 5 min. Contents of serum SIRT1, p53, endothelial nitric oxide synthase(eNOS) and vascular endothelial growth factor(VEGF) were detected by ELISA. Histopathological changes of aortic tissue were observed after HE staining. Expressions of SIRT1 and p53 mRNAs and proteins in aortic tissue were detected by qPCR and Western blot. Compared with the blank group, the model group showed aging symptoms, the prevention group was similar to the blank group, and the treatment group was slightly better than the model group. Compared with the blank group, content of serum p53, expressions of p53 mRNA and protein in aortic tissues were significantly increased (P<0.05, P<0.01), while contents of serum SIRT1, VEGF, eNOS, and expressions of SIRT1 mRNA and protein in aortic tissues were significantly decreased (P<0.05, P<0.01) in the model group. Compared with the model group, content of serum p53, and expression of p53 mRNA and protein in aortic tissues were significantly decreased (P<0.05, P<0.01) in the prevention and treatment groups, while the contents of serum SIRT1, VEGF, eNOS, and the expressions of SIRT1 mRNA and protein in aortic tissues were significantly increased (P<0.05, P<0.01). Compared with the treatment group, rats in the prevention group displayed significant improvement of the above indexes (P<0.05). Compared with the blank group, the endothelial cells were disordered, the vessel wall was significantly thickened, and the senescent cells were increased in the model group; the blood vessel walls were thinner to varying degrees, and the senescent cells were reduced and unevenly distributed in the prevention and treatment groups. The histopathological lesion was improved more obviously in the prevention group than the treatment group. Moxibustion at ST36 can alleviate vascular endothelial injury and oxidative stress in subacute aging rats, which may be related to its effect in regulating the SIRT1/p53 signaling pathway.