Jian-Pi-Yi-Shen Formula Ameliorates Oxidative Stress, Inflammation, and Apoptosis by Activating the Nrf2 Signaling in 5/6 Nephrectomized Rats

Fanyuan Zhou,Dongtao Wang,Ziwei Wang,Jing Zhang,Yajun Yang,Xiaohu Zou

doi:10.3389/fphar.2021.630210

Abstract

Chronic kidney disease (CKD) is an increasing global public health problem, with high morbidity and mortality. Jian-Pi-Yi-Shen (JPYS) formula is a representative traditional Chinese medicine formula in the treatment of CKD, which is widely used in clinical practice in China. However, the underlying mechanism has not been well elucidated. In the present study, we measured the markers of apoptosis, inflammation, oxidative stress, and nuclear factor erythroid 2–related factor 2 (Nrf2) signaling to investigate the effects of JPYS formula on renal function and fibrosis and its molecular mechanism in an established animal model of 5/6 nephrectomized (5/6Nx) rats. The results demonstrated that the JPYS formula exerted a significant preventive effect on renal dysfunction and fibrosis, based on analysis of correlative parameters such as urinary protein, SCr, BUN, glomerular sclerosis index, and tubulointerstitial fibrosis score and renal histopathology and ultrastructural pathology of CKD rats. JPYS formula also induced downregulation of gene expression associated with fibrosis, such as TGF-β and type I, III, and IV collagen. Moreover, the JPYS formula showed a significant protective effect in suppressing cell apoptosis according to the results of apoptotic indexes, including increased gene expression of Bcl-2, decreased gene expression of Bax, caspase 3, caspase 9, and the number of TUNEL-positive cells. JPYS formula also ameliorated the activation of the NF-κB-mediated inflammatory pathway, as manifested by the downregulation of gene expression of TNF-α, IL-1β, IκBα, NF-κB p65, MCP-1, CXCL1, COX-2, and iNOS in the kidney. Our evidence also suggested that the JPYS formula ameliorates oxidative stress by promoting antioxidant function according to antioxidant index indicators as an indicator of GSH, SOD, CAT, and GPx and abating excessive accumulation of the reactive oxygen species biomarkers, including ROS, TBARS, 8-oxo-dG, and MDA. The data also suggested that the JPYS formula reversed the downregulation of HO-1 and Nrf2 level and upregulation of Keap1 expression. Together, our data highlighted that the JPYS formula relieved renal oxidative injury mediated by activation of Nrf2 signaling by inhibiting inflammation and apoptosis in CKD rats.

Highlights

Chronic kidney disease (CKD), characterized by the abnormal structure and degenerative dysfunction of the kidney, may cause a series of deleterious influences on people, contributing to increasing morbidity, disability, mortality, and hospitalization expenses worldwide (Webster et al, 2017)
To evaluate the efficacy of the JPYS formula on the pathological injury of the kidney, a dose-response relationship was firstly ascertained by the biomarkers and ultrastructure related to renal function in the CKD rats
The results showed that impaired renal function of rats in the three groups treated with JPYS formula showed a distinct trend toward reduction in a concentrationdependent manner when compared with the CKD group, based on the correlative parameters, including urinary protein, SCr, blood urea nitrogen (BUN), glomerular sclerosis index, and tubulointerstitial fibrosis score, and a significant difference was observed in the high-dose group (Figures 1A–E)

Summary

Introduction

Chronic kidney disease (CKD), characterized by the abnormal structure and degenerative dysfunction of the kidney, may cause a series of deleterious influences on people, contributing to increasing morbidity, disability, mortality, and hospitalization expenses worldwide (Webster et al, 2017). Despite recent progress in the knowledge on CKD pathogenesis, the treatment is still a challenge and no specific targets and effective therapies are currently available for improving renal function and fibrosis. Nrf can assemble the RNA polymerase machinery and initiate transcription by combining with small Maf proteins (sMaf) and antioxidant responsive elements (ARE) in the promoters of its target genes (Hirotsu et al, 2012). Many Chinese herbs have been demonstrated to promote the accumulation of Nrf and translocation into the nucleus (Zhang et al, 2017) and reinforce gene expression of other antioxidative-related factors (Lu et al, 2019), but whether the possible mechanism of the JPYS formula associates with activation of Nrf signaling pathway remains unknown

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