Superior renoprotective effects of the combination of breviscapine with enalapril and its mechanism in diabetic rats

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.

Scutellarin ameliorates diabetic nephropathy via TGF-β1 signaling pathway

Breviscapine, a natural flavonoid mixture derived from the traditional Chinese herb Erigeron breviscapus (Vant.) Hand-Mazz, has demonstrated a promising potential in improving diabetic nephropathy (DN). However, the specific active constituent(s) responsible for its therapeutic effects and the underlying pharmacological mechanisms remain unclear. In this study, we aimed to investigate the impact of scutellarin, a constituent of breviscapine, on streptozotocin-induced diabetic nephropathy and elucidate its pharmacological mechanism(s). Our findings demonstrate that scutellarin effectively ameliorates various features of DN in vivo, including proteinuria, glomerular expansion, mesangial matrix accumulation, renal fibrosis, and podocyte injury. Mechanistically, scutellarin appears to exert its beneficial effects through modulation of the transforming growth factor-β1 (TGF-β1) signaling pathway, as well as its interaction with the extracellular signal-regulated kinase (Erk) and Wnt/β-catenin pathways.

Mechanisms and efficacy of traditional Chinese herb monomers in diabetic kidney disease

Diabetic kidney disease (DKD) is a serious complication of diabetes and is the primary cause of end-stage renal disease. Current treatment strategies primarily focus on the inhibition of the renin-angiotensin-aldosterone system and the attainment of blood glucose control. Although current medical therapies for DKD have been shown to delay disease progression and improve long-term outcomes, their efficacy is limited and they may be restricted in certain cases, particularly when hyperkalemia is present. Traditional Chinese medicine (TCM) treatment has emerged as a significant complementary approach for DKD. TCM monomers, derived from various Chinese herbs, have been found to modulate multiple therapeutic targets and exhibit a broad range of therapeutic effects in patients with DKD. This review aims to summarize the mechanisms of action of TCM monomers in the treatment of DKD, based on findings from clinical trials, as well as cell and animal studies. The results of these investigations demonstrate the potential effective use of TCM monomers in treating or preventing DKD, offering a promising new direction for future research in the field. By providing a comprehensive overview of the mechanisms and efficacy of TCM monomers in DKD, this review highlights the potential of these natural compounds as alternative therapeutic options for improving outcomes in patients with DKD.

Advances in oxidative stress in pathogenesis of diabetic kidney disease and efficacy of TCM intervention

Diabetic kidney disease (DKD) is a common complication of diabetes and has become the leading cause of end-stage kidney disease. The pathogenesis of DKD is complicated, and oxidative stress is considered as a core of DKD onset. High glucose can lead to increased production of reactive oxygen species (ROS) via the polyol, PKC, AGE/RAGE and hexosamine pathways, resulting in enhanced oxidative stress response. In this way, pathways such as PI3K/Akt, TGF-β1/p38-MAPK and NF-κB are activated, inducing endothelial cell apoptosis, inflammation, autophagy and fibrosis that cause histologic and functional abnormalities of the kidney and finally result in kidney injury. Presently, the treatment for DKD remains an unresolved issue. Traditional Chinese medicine (TCM) has unique advantages for DKD prevention and treatment attributed to its multi-target, multi-component, and multi-pathway characteristics. Numerous studies have proved that Chinese herbs (e.g., Golden Thread, Kudzuvine Root, Tripterygium glycosides, and Ginseng) and patent medicines (e.g., Shenshuaining Tablet, Compound Rhizoma Coptidis Capsule, and Zishen Tongluo Granule) are effective for DKD treatment. The present review described the role of oxidative stress in DKD pathogenesis and the effect of TCM intervention for DKD prevention and treatment, in an attempt to provide evidence for clinical practice.

Advances in understanding and treating diabetic kidney disease: focus on tubulointerstitial inflammation mechanisms

Diabetic kidney disease (DKD) is a serious complication of diabetes that can lead to end-stage kidney disease. Despite its significant impact, most research has concentrated on the glomerulus, with little attention paid to the tubulointerstitial region, which accounts for the majority of the kidney volume. DKD's tubulointerstitial lesions are characterized by inflammation, fibrosis, and loss of kidney function, and recent studies indicate that these lesions may occur earlier than glomerular lesions. Evidence has shown that inflammatory mechanisms in the tubulointerstitium play a critical role in the development and progression of these lesions. Apart from the renin-angiotensin-aldosterone blockade, Sodium-Glucose Linked Transporter-2(SGLT-2) inhibitors and new types of mineralocorticoid receptor antagonists have emerged as effective ways to treat DKD. Moreover, researchers have proposed potential targeted therapies, such as inhibiting pro-inflammatory cytokines and modulating T cells and macrophages, among others. These therapies have demonstrated promising results in preclinical studies and clinical trials, suggesting their potential to treat DKD-induced tubulointerstitial lesions effectively. Understanding the immune-inflammatory mechanisms underlying DKD-induced tubulointerstitial lesions and developing targeted therapies could significantly improve the treatment and management of DKD. This review summarizes the latest advances in this field, highlighting the importance of focusing on tubulointerstitial inflammation mechanisms to improve DKD outcomes.

Radical oxygen species: an important breakthrough point for botanical drugs to regulate oxidative stress and treat the disorder of glycolipid metabolism

Background: The incidence of glycolipid metabolic diseases is extremely high worldwide, which greatly hinders people's life expectancy and patients' quality of life. Oxidative stress (OS) aggravates the development of diseases in glycolipid metabolism. Radical oxygen species (ROS) is a key factor in the signal transduction of OS, which can regulate cell apoptosis and contribute to inflammation. Currently, chemotherapies are the main method to treat disorders of glycolipid metabolism, but this can lead to drug resistance and damage to normal organs. Botanical drugs are an important source of new drugs. They are widely found in nature with availability, high practicality, and low cost. There is increasing evidence that herbal medicine has definite therapeutic effects on glycolipid metabolic diseases. Objective: This study aims to provide a valuable method for the treatment of glycolipid metabolic diseases with botanical drugs from the perspective of ROS regulation by botanical drugs and to further promote the development of effective drugs for the clinical treatment of glycolipid metabolic diseases. Methods: Using herb*, plant medicine, Chinese herbal medicine, phytochemicals, natural medicine, phytomedicine, plant extract, botanical drug, ROS, oxygen free radicals, oxygen radical, oxidizing agent, glucose and lipid metabolism, saccharometabolism, glycometabolism, lipid metabolism, blood glucose, lipoprotein, triglyceride, fatty liver, atherosclerosis, obesity, diabetes, dysglycemia, NAFLD, and DM as keywords or subject terms, relevant literature was retrieved from Web of Science and PubMed databases from 2013 to 2022 and was summarized. Results: Botanical drugs can regulate ROS by regulating mitochondrial function, endoplasmic reticulum, phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT), erythroid 2-related factor 2 (Nrf-2), nuclear factor κB (NF-κB), and other signaling pathways to improve OS and treat glucolipid metabolic diseases. Conclusion: The regulation of ROS by botanical drugs is multi-mechanism and multifaceted. Both cell studies and animal experiments have demonstrated the effectiveness of botanical drugs in the treatment of glycolipid metabolic diseases by regulating ROS. However, studies on safety need to be further improved, and more studies are needed to support the clinical application of botanical drugs.

Breviscapine alleviates podocyte injury by inhibiting NF-κB/NLRP3-mediated pyroptosis in diabetic nephropathy

Podocyte injury is a critical factor in the pathogenesis of diabeticnephropathy (DN). Emerging evidence has demonstrated that breviscapine (Bre) exerts a renoprotective effect on diabetic rats. However, the effects of Bre on regulating podocyte injury under high glucose (HG) conditions remain unclear. In this study, an experimental mouse model of DN was induced by intraperitoneal injections of streptozotocin (STZ) in vivo. The effects of Bre on podocyte injury were assessed using cell counting kit-8 (CCK-8) assay, TdT-mediated dUTPnick-endlabelling (TUNEL) staining, quantitative real-time PCR (qRT‒PCR) and western blot analysis. We found that renal function was significantly decreased in diabetic mice, and this effect was blocked by Bre treatment. Bre effectively increased podocyte viability and inhibited HG-induced cell apoptosis. Furthermore, Bre ameliorated HG-induced podocyte injury, as evidenced by decreased α-smooth muscle actin (α-SMA) expression and increased podocin and synaptopodin expression. Mechanistically, Bre inhibited HG-induced nuclear factorkappaB (NF-κB) signalling activation and subsequently decreased NLR family pyrin domain containing 3 (NLRP3) inflammasome activation, resulting in a decrease in pyroptosis. Pharmacological inhibition of NLRP3 decreased HG-induced podocyte injury, whereas the NLRP3 agonist abrogated the effects of Bre on inhibiting podocyte injury. In summary, these results demonstrate that Bre alleviates HG-induced podocyte injury and improves renal function in diabetic mice, at least in part by inhibiting NF-κB/NLRP3-mediated pyroptosis.

Immune responses in diabetic nephropathy: Pathogenic mechanisms and therapeutic target

Diabetic nephropathy (DN) is a chronic, inflammatory disease affecting millions of diabetic patients worldwide. DN is associated with proteinuria and progressive slowing of glomerular filtration, which often leads to end-stage kidney diseases. Due to the complexity of this metabolic disorder and lack of clarity about its pathogenesis, it is often more difficult to diagnose and treat than other kidney diseases. Recent studies have highlighted that the immune system can inadvertently contribute to DN pathogenesis. Cells involved in innate and adaptive immune responses can target the kidney due to increased expression of immune-related localization factors. Immune cells then activate a pro-inflammatory response involving the release of autocrine and paracrine factors, which further amplify inflammation and damage the kidney. Consequently, strategies to treat DN by targeting the immune responses are currently under study. In light of the steady rise in DN incidence, this timely review summarizes the latest findings about the role of the immune system in the pathogenesis of DN and discusses promising preclinical and clinical therapies.

Scutellarin Improves Type 2 Diabetic Cardiomyopathy by Regulating Cardiomyocyte Autophagy and Apoptosis

Diabetes cardiomyopathy has metabolic disorder and abnormality of cardiomyocytes, which is closely related to autophagy or apoptosis of cardiomyocytes. Scutellarin (SCU) is an important monomer extracted from Erigeron breviscapus (vant.) Hand.-Mazz. This study was conducted to investigate the function of SCU on apoptosis and autophagy of myocardial cells. We established a model of type 2 diabetic cardiomyopathy by high-fat and high-sugar diet. The results indicated that SCU downregulated blood glucose, total cholesterol (TC), triglyceride (TG), and low-density lipoprotein (LDL) levels and upregulated high-density lipoprotein (HDL) level. In addition, SCU downregulated lactic dehydrogenase 1 (LDH1) and creatine kinase (CK) levels. Meanwhile, SCU improved the myocardium morphology and reduced myocardial apoptosis. Furthermore, SCU promoted the mRNA and protein expression of autophagy-related factors (Beclin-1 and LC3-II) and inhibited the mRNA and protein expression of apoptosis-related factors (caspase-3, caspase-8, caspase-9, caspase-12, Bax, and Cyt-C). In conclusion, SCU can promote autophagy signal pathway by upregulating the autophagy-related factors and inhibit the apoptotic signal pathway by downregulating apoptosis-related factors, thereby relieving type 2 diabetic cardiomyopathy (T2DC).

Preparation, Characterization, and Evaluation of Breviscapine Nanosuspension and Its Freeze-Dried Powder

As a biopharmaceutics classification system (BCS) class IV drug, breviscapine (Bre) has low solubility in water, poor chemical stability, a short biological half-life and rapid removal from plasma. This paper prepared a Bre nanosuspension (Bre-NS) by an ultrasound-assisted anti-solvent precipitation method. Characterization of Bre-NS was studied using a Box–Behnken design concerning drug concentration in DMSO, an anti-solvent-to-solvent ratio, and sonication time. Under the optimized conditions of 170 mg/mL for the drug concentration, a 1:60 solvent-to-anti-solvent ratio, and a 9 min sonication time, the particle size of Bre-NS was 303.7 ± 7.3 nm, the polydispersity index was 0.178 ± 0.015, and the zeta potential was −31.10 ± 0.26 mV. Combined with the results from differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and Fourier transform-infrared spectroscopy (FT-IR), the findings indicated that the crystal form and chemical structure of Bre-NS did not change during the entire process. The optimized formulation displayed good stability, increased solubility, and better in vitro release. Therefore, the results of this study can be a reference for the delivery system design of insoluble active components and effective parts in traditional Chinese medicine.

Ameliorative effect of scutellarin on acute alcohol brain injury in mice

Drinking culture has high significance in both China and the world, whether in the entertainment sector or in social occasions; according to the World Health Organization's 2018 Global Alcohol and Health Report, about 3 million people died from excessive drinking in 2016, accounting for 5.3% of the total global deaths that year. Oxidative stress and inflammation are the most common pathological phenomena caused by alcohol abuse (Snyder et al., 2017). Scutellarin, a kind of flavonoid, is one of the main active ingredients extracted from breviscapine. It exerts anti-inflammatory, antioxidant, and vasodilation effects, and has been used to treat cardiovascular diseases and alcoholic liver injury. Although scutellarin can effectively alleviate multi-target organ injury induced by different forms of stimulation, its protective effect on alcoholic brain injury has not been well-defined. Therefore, the present study established an acute alcohol mice brain injury model to explore the effect of scutellarin on acute alcoholic brain injury. The study was carried out based on the targets of oxidative stress and inflammation, which is of great significance for the targeted therapy of clinical alcohol diseases.

Scutellarin alleviates type 2 diabetes (HFD/low dose STZ)-induced cardiac injury through modulation of oxidative stress, inflammation, apoptosis and fibrosis in mice

BACKGROUND

Diabetes is a serious global health concern which severely affected public health as well as socio-economic growth worldwide. Scutellarin (SCU), a bioactive flavonoid, is known for its efficacious action against a range of ailments including cardiovascular problems. The present study was conducted to find out possible protective effect and its associated mechanisms of SCU on experimental type 2 diabetes-induced cardiac injury.

METHODS

Type 2 diabetes was induced by treating animals with high fat diet for 4 weeks and a single intraperitoneal dose (35 mg/kg body weight) of streptozotocin and diabetic animals received SCU (10 or 20 mg/kg/day) for 6 weeks.

RESULTS

Scutellarin attenuated type 2 diabetes-induced hyperglycemia, bodyweight loss, hyperlipidaemia, cardiac functional damage with histopathological alterations and fibrosis. Scutellarin treatment to type 2 diabetic mice ameliorated oxidative stress, inflammatory status and apoptosis in heart. Furthermore, the underlying mechanisms for such mitigation of oxidative stress, inflammation and apoptosis in heart involved modulation of Nrf2/Keap1 pathway, TLR4/MyD88/NF-κB mediated inflammatory pathway and intrinsic (mitochondrial) apoptosis pathway, respectively.

CONCLUSIONS

The current findings suggest that SCU is effective in protecting type 2 diabetes-induced cardiac injury by attenuating oxidative stress and inflammatory responses and apoptosis, and it is also worth considering the efficacious potential of SCU to treat diabetic cardiomyopathy patients.

Melatonin Ameliorates Renal Fibrosis Through the Inhibition of NF-κB and TGF-β1/Smad3 Pathways in db/db Diabetic Mice

OBJECTIVE

To investigate the effects and molecular mechanism of melatonin (MT) on NF-κB and TGF-β/Smad3 signaling pathways in db/db diabetic mice.

METHODS

db/db diabetic mice were divided into five groups treated with melatonin at doses of 50, 100, 200 μg/kg, the urinary concentration was detected by ELISA, renal histology was observed in PAS paining. Mouse mesangial cells were divided into mannitol control group, normal control group, normal control + MT group, high glucose group, high glucose + different concentrations (10, 100, 1000) μmol/L MT group. The proliferation of mesangial cells was detected by EdU kit; the expression of NF-κBp65, ColⅣ and Fn were detected by laser confocal system; the concentrations and mRNA levels of ColⅣ and Fn were detected by ELISA and qRT-PCR. the expressions of ColⅣ, Fn, IκB, p-IκB, TGF-β1, Smad3 and p-Smad3 were detected by Western blot in renal tissues and mesangial cells.

RESULTS

MT treatment could markedly improve the kidney histopathologic lesions. Compared with the db/m mice, 24 h urinary albumin excretion rate (UAER) and the expressions of ColIV, Fn, p-IκB/IκB, NF-κBp65, TGF-β1 and p-Smad3/Smad3 were decreased after melatonin treatment (p <0.05). Compared with the control group, the proliferation function of mesangial cells in high glucose group was significantly enhanced, and the expressions of ColIV, Fn, p-IκB/IκB, NF-κBp65, TGF-β1 and p-Smad3/Smad3 in mesangial cells were significantly up-regulated (p <0.05), and these changes were significantly lowered in MT treatment.

CONCLUSION

Melatonin can inhibit renal inflammation and fibrosis by inhibiting the NF-κB and TGF-β1/Smad3 signaling pathways, and melatonin may be a promising therapeutic target in diabetic nephropathy.

Chinese Herbal Injections for Primary Nephrotic Syndrome in Adults: A Systematic Review and Network Meta-Analysis

Primary nephrotic syndrome (PNS) is a common renal disease that presents with heavy proteinuria and hypoalbuminemia. Despite notable advances in its treatment, some patients show poor responses and clinical outcomes when treated with conventional Western medicine (WM). Chinese herbal injections (CHIs) have been reported to have beneficial effects for PNS. The aim of the present study was to comprehensively determine the efficacy and safety of CHIs for PNS in adults using a network meta-analysis approach. PubMed, Embase, the Cochrane library, and four Chinese databases were systematically searched to identify randomized controlled trials (RCTs) using CHIs for treatment of PNS published before June 1, 2019. Quality assessment of the identified RCTs was performed according to the Cochrane Handbook. Pooled odds ratios (OR) or mean differences (MD) with corresponding 95% confidence intervals (CI) were calculated for discrete or continuous variables, respectively. The primary outcome was complete/total remission and secondary outcomes were serum albumin and urinary protein excretion. The surface under the cumulative ranking curve (SUCRA) value and cluster analyses were used to rank treatment by probability. Eighty-five studies involving 11 CHIs and 5801 subjects were included. Compared with WM alone, CHI plus WM showed an improved complete/total remission rate as well as higher serum albumin and lower 24-hour urinary protein excretion, except in the following: Yinxingye injection plus WM did not improve the total remission rate, and Dengzhanhua or Xueshuantong injection plus WM did not lower the 24-hour urinary protein excretion. Either Danhong (DH) or Dengzhanhua (DZH) injection plus WM was the preferable treatment for PNS based on SUCRA and cluster analyses of clinical remission and adverse events. However, considering that literature in this area is limited, these results need further validation. CHIs administered as adjuvants to WM showed favourable outcomes for PNS. DH + WM and DZH + WM might be the potential optimal therapies for PNS.

Mechanisms of Herbal Nephroprotection in diabetes mellitus

Diabetic nephropathy (DN) is a leading cause of kidney morbidity. Despite the multilayered complexity of the mechanisms involved in the pathogenesis of DN, the conventional treatment is limited to just a few drug classes fraught with the risk of adverse events, including the progression of renal dysfunction. Phytoceuticals offer a promising alternative as they act on the many-sidedness of DN pathophysiology, multitargeting its intricacies. This paper offers a review of the mechanisms underlying the protective action of these phytoagents, including boosting the antioxidant capabilities, suppression of inflammation, averting the proliferative and sclerosing/fibrosing events. The pathogenesis of DN is viewed as a continuum going from the original offense, high glucose, through the noxious products it generates (advanced glycation end-products, products of oxidative and nitrosative stress) and the signaling chains consequently brought into action, to the harmful mediators of inflammation, sclerosis, and proliferation that eventually lead to DN, despite the countervailing attempts of the protective mechanisms. Special attention was given to the various pathways involved, pointing out the ability of the phytoagents to hinder the deleterious ones (especially those leading to, driven by, or associated with TGF-β activation, SREBP, Smad, MAPK, PKC, NF-κB, NLRP3 inflammasome, and caspase), to promote the protective ones (PPAR-α, PPAR-γ, EP4/Gs/AC/cAMP, Nrf2, AMPK, and SIRT1), and to favorably modulate those with potentially dual effect (PI3K/Akt). Many phytomedicines have emerged as potentially useful out of in vitro and in vivo studies, but the scarcity of human trials seriously undermines their usage in the current clinical practice-an issue that stringently needs to be addressed.

Diabetic nephropathy: New insights into established therapeutic paradigms and novel molecular targets

Diabetic nephropathy is one of the most prevalent microvascular complication in patients suffering from diabetes and is reported to be the major cause of renal failure when compared to any other kidney disease. Currently, available therapies provide only symptomatic relief and unable to treat the underlying pathophysiology of diabetic nephropathy. This review will explore new insights into the established therapeutic paradigms targeting oxidative stress, inflammation and endoplasmic reticulum stress with the focus on recent clinical developments. Apart from this, the involvement of novel cellular and molecular mechanisms including the role of endothelin-receptor antagonists, Wnt signaling pathway, epigenetics and micro RNA is also discussed so that key molecular switches involved in the pathogenesis of diabetic nephropathy can be identified. Elucidating new molecular pathways will help in the development of novel therapeutics for the prevention and treatment of diabetic nephropathy.

Effect of breviscapine injection on clinical parameters in diabetic nephropathy: A meta-analysis of randomized controlled trials

Diabetic nephropathy (DN) is currently a major public health problem worldwide. The objective of the present study was to evaluate the clinical effect of breviscapine injections in patients with DN. A meta-analysis was performed using the following databases to obtain published reports in any language: PubMed/MEDLINE, Embase, China National Knowledge Infrastructure, Chinese Evidence-Based Medicine, Wanfang Digital Periodicals, Chinese Academic Journals Full-text Database, Chinese Biological and Medical Database, China Doctoral and Masters Dissertations Full-text Database and the Chinese Proceedings of Conference Full-text Database. Two assessors independently reviewed each trial. A total of 35 randomized controlled trials, which performed studies on a total of 2,320 patients (1,188 in treatment groups and 1,132 in control groups), were included in the present meta-analysis. Data were analyzed using Stata version 11.0 for Windows. The results from the analysis demonstrated that breviscapine injections have greater therapeutic effects in patients with DN in comparison with the control group, including renal protective effects (reducing urine protein, serum creatinine and blood urea nitrogen) and adjustment for dyslipidemia (affecting levels of cholesterol, triglycerides and high density lipoproteins). These effects indicate that breviscapine injections are beneficial to patients with DN. Further studies are required to determine the mechanisms underlying the therapeutic effects of breviscapine.

High glucose induced-macrophage activation through TGF-β-activated kinase 1 signaling pathway

OBJECTIVE AND DESIGN

Transforming growth factor-β-activated kinase 1 (TAK1) plays a pivotal role in innate immune responses and kidney disease, and is critically involved in macrophage activation. However, there is a paucity of data to explore the role of high glucose (HG) in the regulation of TAK1 signaling and its functional role in macrophage activation. We assume that TAK1 signaling in hyperglycemic condition could be a key factor leading to macrophage activation and inflammation response.

METHODS

Mice macrophages were seeded on a 96-well cell culture plate; cell viability was tested after treatment with different concentration of TAK1 inhibitors. Cells were divided into groups (OZ300; MC; NC; HG; HG + OZ30, 100, 300 nM) and treated for given time course. Monocyte chemotactic protein1(MCP-1) and tumor necrosis factor-α (TNF-α) mRNA levels were evaluated by qRT-PCR. Flow cytometry and confocal microscopy are used to analyse the activated macrophage induced by HG. Expression levels of p-TAK1, TAB 1, p-JNK, p-p38MAPK, NF-κBpp65 were detected by western blot. Nuclear translocation of NF-κBp65 was assessed by confocal microscopy.

RESULTS

Our data revealed that high glucose not only significantly increased macrophage activation and subsequently abnormal high-expression of MCP-1 and TNF-α, but likewise remarkably enhanced TAK1 activation, MAPK phosphorylation, NF-κB expression in macrophages. Furthermore, pharmacological inhibition of TAK1 attenuated high glucose-triggered signal pathways, macrophage activation and inflammatory cytokines in a simulated diabetic environment.

CONCLUSION

Our findings suggested that high glucose activated macrophages mainly in TAK1/MAPKs and TAK1/NF-κB-dependent manners, which lead to the polarization of macrophages towards a pro-inflammatory phenotype, and finally lead to diabetic nephropathy. In sum, the study raises novel data about the molecular mechanisms involved in the high glucose-mediated inflammatory response in macrophages.

Blockade of TGF-β-activated kinase 1 prevents advanced glycation end products-induced inflammatory response in macrophages

Advanced glycation end products (AGEs), inflammatory-activated macrophages are essential in the initiation and progression of diabetic nephropathy (DN). TGF-β-activated kinase 1 (TAK1) plays a vital role in innate immune responses and inflammation. However, little information has been available about the effects of AGEs on the regulation of TAK1 expression and underlying mechanisms in AGEs-stimulated macrophage activation. We hypothesized TAK1 signal pathway in AGEs conditions could be a vital factor contributing to macrophage activation and inflammation. Thus, in the present study, we used bone marrow-derived macrophages (BMMs) to explore the functional role and potential mechanisms of TAK1 pathway under AGEs conditions. Results indicated that TAK1 played important roles in AGEs-induced mitogen-activated protein kinases (MAPKs) and nuclear factor kappa B protein (NF-κB) activation, which regulated the production of monocyte chemo-attractant protein-1 (MCP-1) and tumor necrosis factor-alpha (TNF-α) in AGEs-stimulated macrophages. The results also suggested that TAK1 inhibitor (5Z-7-oxozeaenol) could inhibit AGEs-induced macrophage activation to down-regulate inflammatory cytokine production via MAPKs and NF-κB pathways, indicating that 5Z-7-oxozeaenol might be an immunoregulatory agent against AGEs-stimulated inflammatory response in DN.

Therapeutic effect and mechanism of breviscapine on cisplatin-induced nephrotoxicity in mice

OBJECTIVE

To observe the protective effect of breviscapine on mice with cisplatin-induced nephrotoxicity.

METHODS

Mice were given a single injection of cisplatin (8 mg/kg, i.p.); then, breviscapine was given to mice at 25 mg/kg and 50 mg/kg doses, respectively, once a day for seven days. Renal tissue structure was observed after animals were sacrificed. Blood urea nitrogen (BUN), serum creatinine (Scr), lipid peroxide (MDA) and superoxide dismutase (SOD) serum levels were detected; and MDA, glutathione peroxidase, and SOD levels in the renal cortex were detected.

RESULTS

Compared with the blank control group (BCG), the kidney pathological damage of mice in the model control group (MCG) was more severe. After applying different doses of breviscapine, different degrees of renal injury improvement appeared. Compared with the BCG, the serum levels of Scr and BUN in the MCG increased to (89.92 ± 6.78) μmoL/Land (15.32 ± 4.53) mmoL/L. The differences were statistical significant (P < 0.01). Compared with the MCG, the serum levels of Scr and BUN in the Bre low-dose groups and Bre high-dose groups decreased significantly (P < 0.05). Compared with the BCG, the MDA levels in serum and in the renal cortex in the MCG significantly increased, while the SOD levels significantly decreased. Both the differences were statistically significant (P < 0.01). In the Bre low-dose groups and Bre high-dose groups, MDA levels in serum and in the renal cortex significantly decreased, while SOD and glutathione peroxidase levels in the renal cortex significantly increased, compared with the MCG; and the differences were statistically significant (P < 0.05).

CONCLUSIONS

Breviscapine can reduce cisplatin-induced renal toxicity in mice and it's possible through inhibition of renal tubule cell lipid peroxidation and reduces the nephrotoxicity of cisplatin.

The anti-inflammatory and antifibrotic effects of Coreopsis tinctoria Nutt on high-glucose-fat diet and streptozotocin-induced diabetic renal damage in rats

Background

Diabetic nephropathy is a serious complication of diabetes whose development process is associated with inflammation, renal hypertrophy, and fibrosis. Coreopsis tinctoria Nutt, traditionally used as a healthcare tea, has anti-inflammatory, anti-hyperlipidemia, and glycemic regulation activities. The aim of our study was to investigate the renal protective effect of ethyl acetate extract of C. tinctoria Nutt (AC) on high-glucose–fat diet and streptozotocin (STZ)-induced diabetic rats.

Methods

A diabetic rat model was induced by high-glucose–fat diet and intraperitoneal injection of 35 mg/kg STZ. After treatment with AC at a daily dose of 150, 300 or, 600 mg/kg for 4 weeks, metabolic and renal function parameters of serum and urine were examined. Degree of renal damage, renal proinflammatory cytokines, and fibrotic protein expression were analyzed by histopathology and immunohistochemistry. Renal AMP-activated protein kinase (AMPK) and transforming growth factor (TGF)-β1/Smad signaling pathway were determined by western blotting.

Results

Diabetic rats showed obvious renal dysfunction, inflammation and fibrosis. However, AC significantly reduced levels of blood glucose, total cholesterol, triglyceride, blood urea nitrogen, serum creatinine and urinary albumin, as well as expression of kidney proinflammatory cytokines of monocyte chemoattractant protein-1 and intercellular adhesion molecule-1. AC also ameliorated renal hypertrophy and fibrosis by reducing fibronectin and collagen IV and suppressing the TGF-β1/Smad signaling pathway. Meanwhile, AMPKα as a protective cytokine was markedly stimulated by AC.

Conclusion

In summary, AC controls blood glucose, inhibits inflammatory and fibrotic processes, suppresses the TGF-β1/Smad signaling pathway, and activates phosphorylation of AMPKα in the kidneys, which confirms the protective effects of AC in the early stage of diabetic kidney disease.

Protective effects of scutellarin on type II diabetes mellitus-induced testicular damages related to reactive oxygen species/Bcl-2/Bax and reactive oxygen species/microcirculation/staving pathway in diabetic rat

The goal of our study is to evaluate the effect of Scutellarin on type II diabetes-induced testicular disorder and show the mechanism of Scutellarin's action. We used streptozotocin and high-fat diet to establish type II diabetic rat model. TUNEL and haematoxylin and eosin staining were used to evaluate the testicular apoptotic cells and morphologic changes. Immunohistochemical staining was used to measure the expression level of vascular endothelial growth factor and blood vessel density in testes. Oxidative stress in testes and epididymis was tested by fluorescence spectrophotometer and ELISA. The expression of Bcl-2/Bax and blood flow rate in testicular vessels were measured by western blot and Doppler. Our results for the first time showed that hyperglycemia induced apoptotic cells and morphologic impairments in testes of rats, while administration of Scutellarin can significantly inhibit these damages. This effect of Scutellarin is controlled by two apoptotic triggers: ROS/Bcl-2/Bax and ROS/microcirculation/starving pathway.

Simultaneous determination of three glucuronide conjugates of scutellarein in rat plasma by LC-MS/MS for pharmacokinetic study of breviscapine

A selective and sensitive LC-MS/MS method was developed and validated for simultaneous determination of three glucuronide conjugates of scutellarein in rat plasma. Plasma samples were pretreated by protein precipitation with acetonitrile. The analytes (scutellarin, scutellarein-6,7-di-O-β-d-glucuronide and scutellarein-6-O-β-d-glucuronide), together with internal standard (IS, baicalin) were separated on a Diamonsil C18 column (150 mm × 4.6 mm, 5 μm) with an isocratic mobile phase consisting of methanol-water-formic acid (55:45:0.2, v/v/v). Mass spectrometric detection was performed by selected reaction monitoring (SRM) mode via electrospray ionization source operating in negative ionization mode. The method was linear for all the analytes over the investigated concentration ranges with correlation coefficients greater than 0.9954. The intra- and inter-day precisions were less than 9.1% and the relative error was between -1.7% and 4.2%. The extraction recoveries of the analytes and IS from rat plasma were over 63%. The validated method has been successfully applied to a pharmacokinetic study of breviscapine in rats after intragastric administration at a dose of 20mg/kg. The pharmacokinetic results would be helpful to better understand the pharmacological actions of breviscapine.

The renoprotective effects of berberine via the EP4-Gαs-cAMP signaling pathway in different stages of diabetes in rats

AIMS

To investigate the renoprotective roles of berberine (BBR) in different stages of diabetic nephropathy (DN) in streptozotocin (STZ)-induced diabetic rats fed a high-sugar and high-fat diet.

METHODS

Diabetes was induced in mice by intraperitoneal injection of STZ, and the mice were then randomly divided into groups: normal, diabetes, high-sugar and high-fat and BBR (high, median and low dose) groups. The body weight (BW), kidney weight to body weight (KW/BW), blood urea nitrogen, urine total protein to urine creatinine ratio and serum creatinine were measured on different weeks throughout the study. The protein levels of E prostanoid receptor 4 (EP4), Gαs and content of cAMP in the kidney were, respectively, detected by western blot analysis and RIA analysis.

RESULTS

In the DN rats, there was remarkable renal damage. BBR restored renal functional parameters, suppressed alterations in histological and ultrastructural changes in the kidney tissues and increased EP4, Gαs and cAMP levels compared with those of the DN model group. In addition, BBR has different therapeutic effects during the different stages of the development of DN, and it works best in the sixth week.

CONCLUSION

These studies demonstrate, for the first time, that BBR exerts renoprotective effects in different stages of DN via EP4- Gαs- AC-cAMP signaling pathway in STZ-induced DN rats fed a high-sugar and high-fat diet.