Sanziguben polysaccharides inhibit diabetic nephropathy through NF-κB-mediated anti-inflammation

Chinese herbal medicine for the treatment of diabetic nephropathy: From clinical evidence to potential mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetic nephropathy (DN) is a typical chronic microvascular complication of diabetes, characterized by proteinuria and a gradual decline in renal function. At present, there are limited clinical interventions aimed at preventing the progression of DN to end-stage renal disease (ESRD). However, Chinese herbal medicine presents a distinct therapeutic approach that can be effectively combined with conventional Western medicine treatments to safeguard renal function. This combination holds considerable practical implications for the treatment of DN.

AIM OF THE STUDY

This review covers commonly used Chinese herbal remedies and decoctions applicable to various types of DN, and we summarize the role played by their active ingredients in the treatment of DN and their mechanisms, which includes how they might improve inflammation and metabolic abnormalities to provide new ideas to cope with the development of DN.

MATERIALS AND METHODS

With the keywords "diabetic nephropathy," "Chinese herbal medicine," "clinical effectiveness," and "bioactive components," we conducted an extensive literature search of several databases, including PubMed, Web of Science, CNKI, and Wanfang database, to discover studies on herbal formulas that were effective in slowing the progression of DN. The names of the plants covered in the review have been checked at MPNS (http://mpns.kew.org).

RESULTS

This review demonstrates the superior total clinical effective rate of combining Chinese herbal medicines with Western medicines over the use of Western medicines alone, as evidenced by summarizing the results of several clinical trials. Furthermore, the review highlights the nephroprotective effects of seven frequently used herbs exerting beneficial effects such as podocyte repair, anti-fibrosis of renal tissues, and regulation of glucose and lipid metabolism through multiple signaling pathways in the treatment of DN.

CONCLUSIONS

The potential of herbs in treating DN is evident from their excellent effectiveness and the ability of different herbs to target various symptoms of the condition. However, limitations arise from the deficiencies in interfacing with objective bioindicators, which hinder the integration of herbal therapies into modern medical practice. Further research is warranted to address these limitations and enhance the compatibility of herbal therapies with contemporary medical standards.

NF-ĸB axis in diabetic neuropathy, cardiomyopathy and nephropathy: A roadmap from molecular intervention to therapeutic strategies

Diabetes mellitus (DM) is a metabolic illness defined by elevated blood glucose levels, mediating various tissue alterations, including the dysfunction of vital organs. Diabetes mellitus (DM) can lead to many consequences that specifically affect the brain, heart, and kidneys. These issues are known as neuropathy, cardiomyopathy, and nephropathy, respectively. Inflammation is acknowledged as a pivotal biological mechanism that contributes to the development of various diabetes consequences. NF-κB modulates inflammation and the immune system at the cellular level. Its abnormal regulation has been identified in several clinical situations, including cancer, inflammatory bowel illnesses, cardiovascular diseases, and Diabetes Mellitus (DM). The purpose of this review is to evaluate the potential impact of NF-κB on complications associated with DM. Enhanced NF-κB activity promotes inflammation, resulting in cellular harm and compromised organ performance. Phytochemicals, which are therapeutic molecules, can potentially decline the NF-κB level, therefore alleviating inflammation and the progression of problems correlated with DM. More importantly, the regulation of NF-κB can be influenced by various factors, such as TLR4 in DM. Highlighting these factors can facilitate the development of novel therapies in the future.

Salvianolic acid B attenuates diabetic nephropathy through alleviating ADORA2B, NALP3 in flammasome, and NFκB activity

Diabetic nephropathy is one of the microvascular complications of diabetes. This study is aimed at investigating the role and mechanisms of salvianolic acid B (Sal B) in diabetic nephropathy. High glucose (HG)-induced human renal tubular epithelial HK-2 cells were treated with Sal B, BAY-60-6583 (agonist of adenosine 2B receptor), or PSB-603 (antagonist of adenosine 2B receptor) for 24 h. Adenosine A2b receptor (ADORA2B), NACHT, leucine-rich repeat (LRR), and pyrin (PYD) domains-containing protein 3 (NALP3), and nuclear factor Kappa B (NFκB) expressions, mitochondrial membrane potential (MMP), and reactive oxygen species (ROS) levels were examined. Following 6 weeks of Sal B treatment, db/db mice blood and kidney tissue were harvested for biochemical detection with hematoxylin-eosin (H&E), Masson's, periodic acid schiff (PAS), and Sirius red staining and detection of ADORA2B, NALP3, NFκB, interleukin 1β (IL-1β), and toll-like receptor 4 (TLR4) activity. NFκB, NALP3, and ADORA2B were found to be downregulated in Sal B treated HK-2 cells exposed to high glucose (HG), accompanied by elevated levels of MMPs and reduced intracellular ROS production. Sal B-treated diabetic mice had the improvement in body weight, water intake, hyperglycemia, hyperlipidemia, and liver and kidney function. Altogether, Sal B attenuates HG-induced kidney tubule cell injury and diabetic nephropathy in diabetic mice, providing clues to other novel mechanisms by which Sal B is beneficial in diabetic nephropathy.

Sanziguben polysaccharides improve diabetic nephropathy in mice by regulating gut microbiota to inhibit the TLR4/NF-κB/NLRP3 signalling pathway

CONTEXT

Sanziguben (SZGB) is an empirical prescription used in traditional Chinese medicine to treat diabetic nephropathy (DN). As an abundant and primarily effective component of SZGB, Sanziguben polysaccharides (SZP) can be digested by flora to generate biological activity.

OBJECTIVE

Our study aimed to clarify the potential mechanism of SZP in improving chronic DN.

MATERIALS AND METHODS

Male db/db mice were randomized into DN, SZP (500 mg/kg) and metformin (MET, 300 mg/kg) groups. Wild-type littermates served as the normal control (NC) group. The drug was orally administered for 8 weeks. Enzyme-linked immunosorbent assay was used to detect the inflammatory factors. Proteins related to inflammation were evaluated using western blotting and immunohistochemical examination. Gut microbiota was analysed using 16S rRNA sequencing.

RESULTS

SZP significantly reduced 24 h urine albumin (p < 0.05) of DN mice. Compared to DN group, SZP significantly decreased the homeostasis model assessment of insulin resistance index, serum creatinine and blood urea nitrogen levels (20.27 ± 3.50 vs. 33.64 ± 4.85, 19.22 ± 3.77 vs. 32.52 ± 3.05 μmol/L, 13.23 ± 1.42 vs. 16.27 ± 0.77 mmol/L, respectively), and mitigated renal damage. SZP also regulated gut microbiota and decreased the abundance of Gram-negative bacteria (Proteobacteria, Klebsiella and Escherichia-Shigella). Subsequently, SZP reduced lipopolysaccharides levels (1.06- to 1.93-fold) of DN mice. Furthermore, SZP inhibited the expression levels of TLR4, phospho-NF-κB p65, NLRP3 proteins and interleukin (IL)-18 and IL-1β.

CONCLUSIONS

These results demonstrated that SZP improved intestinal flora disorder and inhibited the TLR4/NF-κB/NLRP3 pathway to alleviate DN.

The role of discoid domain receptor 1 on renal tubular epithelial pyroptosis in diabetic nephropathy

Pyroptosis, a form of cell death associated with inflammation, is known to be involved in diabetic nephropathy (DN), and discoid domain receptor 1 (DDR1), an inflammatory regulatory protein, is reported to be associated with diabetes. However, the mechanism underlying DDR1 regulation and pyroptosis in DN remains unknown. We aimed to investigate the effect of DDR1 on renal tubular epithelial cell pyroptosis and the mechanism underlying DN. In this study, we used high glucose (HG)-treated HK-2 cells and rats with a single intraperitoneal injection of streptozotocin as DN models. Subsequently, the expression of pyroptosis-related proteins (cleaved caspase-1, GSDMD-N, Interleukin-1β [IL-1β], and interleukin-18 [IL-18]), DDR1, phosphorylated NF-κB (p-NF-κB), and NLR family pyrin domain-containing 3 (NLRP3) inflammasomes were determined through Western blotting. IL-1β and IL-18 levels were determined using ELISA. The rate of pyroptosis was assessed by propidium iodide (PI) staining. The results revealed upregulated expression of pyroptosis-related proteins and increased concentration of IL-1β and IL-18, accompanied by DDR1, p-NF-κB, and NLRP3 upregulation in DN rat kidney tissues and HG-treated HK-2 cells. Moreover, DDR1 knockdown in the background of HG treatment resulted in inhibited expression of pyroptosis-related proteins and attenuation of IL-1β and IL-18 production and PI-positive cell frequency via the NF-κB/NLRP3 pathway in HK-2 cells. However, NLRP3 overexpression reversed the effect of DDR1 knockdown on pyroptosis. In conclusion, we demonstrated that DDR1 may be associated with pyroptosis, and DDR1 knockdown inhibited HG-induced renal tubular epithelial cell pyroptosis. The NF-κB/NLRP3 pathway is probably involved in the underlying mechanism of these findings.