Losartan inhibited atherosclerosis in experimental renal failure by regulating Treg /Th17 cells immune balance

Abstract

Objective To explore the effects and mechanisms of losartan on atheroscleorsis and T cell (Treg/Th17) immune balance of CKD apolipoprotein E knockout (ApoE-/-) mice. Methods The model of CKD was induced by a 5/6 nephrectomy (SNx) in male ApoE-/- mice. ApoE-/- mice were randomly allocated into 3 subgroups: the control group, SNx group and losartan group. The fifth week after building model the mice in losartan group were taken losartan at a dose of 30 mg/(kg·d) by intragastric administration for 12 weeks. While the other mice were treated with the same volume of 0.5% sodium carboxymethylcellulose. Sixteen weeks after nephrectomy, the serum levels of urea and creatinine were determined. Haematoxylin Eosin (HE) staining were used to observe the general morphology changes of atherosclerotic plaque. Flow cytometry was performed to detect the proportion of T cells (Treg/Th17) in spleen. Enzyme linked immunosorbent assay (ELISA) was performed to detect the level of cytokines in serum such as interleukin (IL)-17, IL-6, transforming growth factor-β1 (TGF-β1) and IL-10. Results Sixteen weeks after nephrectomy, the result of serum creatinine and urea nitrogen showed the CKD animal model established successfully. Losartan could improved the renal function of CKD mice. The size of aortic root plaques in control group, SNx group, and losartan group are (16.35±3.72)×104 μm2, (28.64±5.86)×104 μm2 and (22.76±3.97)×104 μm2 respectively, indicating that losartan treatment significantly decreased the size of aortic root plaques of the CKD mice (P<0.05). The proportion of Treg cells in the spleen of control group, SNx group, and losartan group are (4.34±0.93)%, (1.78±0.56)%, and (2.68±0.58)% respectively, indicating that losartan treatment significantly increased the proportion of Treg cells of CKD mice (P<0.01). The proportion of Th17 cells in the spleen of control group, SNx group, and losartan group are (0.11±0.06)%, (0.67±0.12)%, (0.37±0.08)% respectively, indicating that losartan treatment significantly decreased the proportion of Th17 cells of CKD mice (P<0.01). Compared with control mice, the level of cytokines TGF-β1 and IL-10 in the serum of the SNx group mice significantly decreased (P<0.01), and the level of cytokines IL-17 and IL-6 in the serum of the SNx group mice significantly increased (P<0.01), indicating that such effects could be significantly regulated by losartan (P<0.05). Conclusions Losartan inhibited the differentiation of Th17 cell subsets, promoted the differentiation of Treg, and alleviated atherosclerosis in CKD ApoE-/- mice by modulating the immune imbalance of the Treg/Th17 cell. Key words: Kidney diseases/CO/IM; Atherosclerosis/CO/IM; Losartan/PD; T-lymphocytes, regulatory; Th17 cells; Mice