Bu-Shen-Huo-Xue Decoction Ameliorates Diabetic Nephropathy by Inhibiting Rac1/PAK1/p38MAPK Signaling Pathway in High-Fat Diet/Streptozotocin-Induced Diabetic Mice.

Weisong Wang,Hongping Long,Wei Huang,Jianhe Liu,Dan Xiong,Ting Zhang,Lihua Xie,Wei Hu,Cheng Chen

doi:10.3389/fphar.2020.587663

Abstract

Diabetic nephropathy (DN), a leading cause of end-stage renal disease, is associated with high morbidity and mortality rates worldwide and the development of new drugs to treat DN is urgently required. Bu-Shen-Huo-Xue (BSHX) decoction is a traditional Chinese herbal formula, made according to traditional Chinese medicine (TCM) theory, and has been used clinically to treat DN. In the present study, we established a high-fat diet/streptozotocin-induced diabetic mouse model and treated the mice with BSHX decoction to verify its therapeutic effects in vivo. Ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was applied to analyze the chemical composition and active compounds of BSHX decoction. Markers of podocyte epithelial-mesenchymal transition and the Rac1/PAK1/p38MAPK signaling pathway were evaluated to investigate the mechanism underlying function of BSHX decoction. BSHX decoction effectively alleviated diabetic symptoms, according to analysis of the renal function indicators, serum creatinine, blood urea nitrogen, serum uric acid, and urinary albumin excretion rate, as well as renal histopathology and ultrastructural pathology of DN mice. We identified 67 compounds, including 20 likely active compounds, in BSHX decoction. The podocyte markers, nephrin and podocin, were down-regulated, while the mesenchymal markers, α-SMA and FSP-1, were up-regulated in DN mouse kidney; however, the changes in these markers were reversed on treatment with BSHX decoction. GTP-Rac1 was markedly overexpressed in DN mice and its levels were significantly decreased in response to BSHX decoction. Similarly, levels of p-PAK1 and p-p38MAPK which indicate Rac1 activation, were reduced on treatment with BSHX decoction. Together, our data demonstrated that BSHX decoction ameliorated renal function and podocyte epithelial-mesenchymal transition via inhibiting Rac1/PAK1/p38MAPK signaling pathway in high-fat diet/streptozotocin-induced diabetic mice. Further, we generated a quality control standard and numerous potential active compounds from BSHX decoction for DN.

Highlights

Diabetes is a group of metabolic diseases, mainly caused by defects in insulin secretion, insulin activity, or both (American Diabetes Association, 2013)
We found that treatment with BSHX decoction significantly lowered serum TG and total cholesterol (TC) levels, which were increased in the Diabetic nephropathy (DN) group, in a dose-dependent manner (Figures 1F,G)
DN is a diagnosis that refers to specific pathologic structural and functional changes in the kidneys of patients with both type 1 and type 2 diabetes mellitus (T1/T2DM), that results from the effects of DM on the kidney (Umanath and Lewis, 2018), and is a leading causes of end-stage renal disease (Sanajou et al, 2018)

Summary

Introduction

Diabetes is a group of metabolic diseases, mainly caused by defects in insulin secretion, insulin activity, or both (American Diabetes Association, 2013). The number of people suffering from diabetes is predicted to rise to 590 million by 2,035 worldwide, while approximately 5.1 million individuals died from diabetes and its complications in 2013 (Sen and Chakraborty, 2015). Diabetic nephropathy (DN) is a common complication of diabetes. DN can lead to uremia, and macrovascular complications, such as heart attacks and strokes, which can be fatal (Forbes and Cooper, 2013). Dysfunction or injury of podocyte, key components of the glomerular filtration barrier, has been proposed as the core pathophysiology underlying DN (Torban et al, 2019). Epithelial-mesenchymal transition (EMT) is primary mechanisms of podocyte injury (Dai et al, 2017). During EMT, epithelial cells lose their hallmark epithelial characteristics and gain the features of mesenchymal cells; this process can be regulated by several signaling pathways (Ying and Wu, 2017)

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Conclusion