Huangkui capsule in combination with metformin ameliorates diabetic nephropathy via the Klotho/TGF-β1/p38MAPK signaling pathway

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.

A single-cell profile reveals the transcriptional regulation responded for Abelmoschus manihot (L.) treatment in diabetic kidney disease

BACKGROUND

Huangkui capsule (HKC), as an ethanol extract of Abelmoschus manihot (L.), has a significant efficacy in treatment of the patients with diabetic kidney disease (DKD). The bioactive ingredients of HKC mainly include the flavonoids such as rutin, hyperoside, hibifolin, isoquercetin, myricetin, quercetin and quercetin-3-O-robinobioside.

PURPOSE

To explore the molecular mechanisms of A. manihot in treatment of DKD.

STUDY DESIGN

A single-cell RNA sequencing analysis of kidneys in db/db mice with and without HKC administration.

METHODS

Urinary biochemical and histopathological examination in C57BL/6 and db/db mice of DKD and HKC groups was done. Single-cell RNA sequencing pipeline was then performed. The regulatory mechanisms of seven flavonoids in HKC were revealed by cell communication, prediction of transcription factor regulatory network, and molecular docking.

RESULTS

By constructing ligand-receptor regulatory network and performing molecular docking between 75 receptors with different activities and seven flavonoids. 11 key receptors in 4 cell types (segment 3 proximal convoluted tubular cell, ascending limbs of the loop of Henle, distal convoluted tubule, and T cell) in kidneys were found to be directly interacted with HKC. The interactions regulated 8 downstream regulons. The docking receptors in T cell led to transcriptional event differences in the regulons such as Cebpb, Rel, Tbx21 and Klf2 and consequently affected the activation, differentiation, and infiltration of T cell, while the receptors Tgfbr1 and Ldlr in stromal cells of kidneys were closely associated with the downstream transcriptional events of renal injury and proteinuria in DKD.

CONCLUSION

The current study provides novel information of the key receptors and regulons in renal cells for a better understanding of the cell type specific molecular mechanisms of A. manihot in treatment of DKD.

Pegylated polymeric micelles of boswellic acid-selenium mitigates repetitive mild traumatic brain injury: Regulation of miR-155 and miR-146a/BDNF/ Klotho/Foxo3a cue

This study aims to explore the protective machinery of pegylated polymeric micelles of boswellic acid-selenium (PMBS) against secondary neuronal damage triggered by mild repetitive traumatic brain injury (RTBI). After PMBS characterization in terms of particle size, size distribution, zeta potential, and transmission electronic microscopy, the selected formula was used to investigate its potency against experimental RTBI. Five groups of rats were used; group 1 (control) and the other four groups were subjected to RTBI. Groups 2 was RTBI positive control, while 3, 4, and 5 received boswellic acid (BSA), selenium (SEL), and PMBS, respectively. The open-field behavioral test was used for behavioral assessment. Subsequently, brain tissues were utilized for hematoxylin and eosin staining, Nissl staining, Western blotting, and ELISA in addition to evaluating microRNA expression (miR-155 and miR-146a). The behavioral changes, oxidative stress, and neuroinflammation triggered by RTBI were all improved by PMBS. Moreover, PMBS mitigated excessive glutamate-induced excitotoxicity and the dysregulation in miR-155 and miR-146a expression. Besides, connexin43 (Cx43) expression as well as klotho and brain-derived neurotrophic factor (BDNF) were upregulated with diminished neuronal cell death and apoptosis because of reduced Forkhead Box class O3a(Foxo3a) expression in the PMBS-treated group. The current study has provided evidence of the benefits produced by incorporating BSA and SEL in PEGylated polymeric micelles formula. PMBS is a promising therapy for RTBI. Its beneficial effects are attributed to the manipulation of many pathways, including the regulation of miR-155 and miR-146a expression, as well as the BDNF /Klotho/Foxo3a signaling pathway.

Traditional Chinese medicine for the treatment of immune-related nephropathy: A review

Immune-related nephropathy (IRN) refers to immune-response-mediated glomerulonephritis and is the main cause of end-stage renal failure. The pathogenesis of IRN is not fully understood; therefore, treatment is challenging. Traditional Chinese medicines (TCMs) have potent clinical effects in the treatment of the IRN conditions immunoglobulin A nephropathy, lupus nephropathy, and diabetic nephropathy. The underlying mechanisms mainly include its inhibition of inflammation; improvements to renal interstitial fibrosis, oxidative stress, autophagy, apoptosis; and regulation of immunity. In this review, we summarize the clinical symptoms of the three IRN subtypes and the use of TCM prescriptions, herbs, and bioactive compounds in treating IRN, as well as the potential mechanisms, intending to provide a reference for the future study of TCM as IRN treatments.

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.

Network pharmacology and molecular docking predictions of the active compounds and mechanism of action of Huangkui capsule for the treatment of idiopathic membranous nephropathy

BACKGROUND

Huangkui Capsule is a single herbal concoction prepared from the flower of Abelmoschus manihot, which is used to treat idiopathic membranous nephropathy (IMN), a frequent pathologically damaging kidney condition. It has been widely utilized to treat a variety of renal disorders, including IMN, in clinical practice. However, the active compounds and mechanism of action underlying the anti-IMN effects of Huangkui Capsule remain unclear. In this study, we aimed to predict the potential active compounds and molecular targets of Huangkui Capsule for the treatment of IMN.

METHODS

The possible active components of Huangkui were located using the SymMap v2 database. The targets of these drugs were predicted using Swiss Target Prediction, while IMN-related genes with association scores under 5 were gathered from the GeneCards and DisGeNET databases. The common targets of the disease and the components were determined using VENNY 2.1. Using Cytoscape 3.8.0, a drug-disease network diagram was created. Molecular docking was carried out with Pymol, AutoDock Tools, and AutoDock Vina.

RESULTS

With 1260 IMN-related illness genes gathered from GeneCards and DisGeNET databases, we were able to identify 5 potentially active chemicals and their 169 target proteins in Huangkui. Based on degree value, the top 6 targets for Huangkui treatment of IMN were chosen, including AKT, MAPK3, PPARG, MMP9, ESR1, and KDR.

CONCLUSION

This work theoretically explains the mechanism of action of Huangkui Capsule in treating IMN and offers a foundation for using Huangkui Capsule in treating IMN in clinical settings. The findings require additional experimental validation.

Inverse J-Shaped Relationship of Dietary Carbohydrate Intake with Serum Klotho in NHANES 2007-2016

BACKGROUND

The relationship between dietary carbohydrate intake and serum Klotho levels, an aging biomarker, remains uncertain.

OBJECTIVE

This study aimed to investigate the association between dietary carbohydrate intake and serum Klotho levels among American adults aged 40-79.

METHODS

We analyzed data from 10,669 adults aged 40-79 years who participated in the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2016. Trained interviewers assessed dietary carbohydrate intake using a 24 h dietary recall. Serum Klotho concentrations were measured using commercially available ELISA kits provided by IBL International, Japan, which served as the study outcome. Generalized linear models were used to assess the relationship between the carbohydrate energy percentage and serum Klotho concentration, and restricted cubic spline (RCS) analysis was employed to explore any nonlinear associations.

RESULTS

After adjusting for multiple variables, we observed a nonlinear inverse J-shaped relationship (p for non-linearity < 0.001) between the carbohydrate energy percentage and serum Klotho levels. Specifically, the highest serum Klotho levels were associated with a total carbohydrate energy percentage ranging from 48.92% to 56.20% (third quartile). When the carbohydrate energy percentage was evaluated in quartiles, serum Klotho levels decreased by 5.37% (95% CI: -7.43%, -3.26%), 2.70% (95% CI: -4.51%, -0.86%), and 2.76% (95% CI: -4.86%, -0.62%) in the first quartile (<41.46%), second quartile (41.46% to 48.92%), and fourth quartile (≥56.20%), respectively, compared to the third quartile. This relationship was more pronounced in male, non-obese and non-diabetic participants under 60 years of age.

CONCLUSION

A non-linear inverse J-shaped relationship exists among the general U.S. middle-aged and older population between the carbohydrate energy percentage and serum Klotho levels, with the highest levels observed at 48.92% to 56.20% carbohydrate intake.

Klotho gene might antagonize ischemic injury in stroke rats by reducing the expression of AQP4 via P38MAPK pathway

OBJECTIVES

This study was aimed at exploring whether klotho improved neurologic function in rats with cerebral infarction by inhibiting P38 mitogen-activated protein kinase (MAPK) activation and thus down-regulating aquaporin 4 (AQP4).

METHODS

In this study, we induced intracerebral Klotho overexpression in 6-week-old Sprague Dawley rats by injecting lentivirus carrying full-length rat Klotho cDNA into the lateral ventricle of the brain, followed by middle cerebral artery occlusion (MCAO) surgery after three days. Neurologic function was evaluated by neurological deficit scores. Infarct volume was assessed by 2,3,5-triphenyl tetrazolium chloride (TTC) staining. The expressions of Klotho, AQP4, and P38 MAPK were detected by Western blot and Immunofluorescence.

RESULTS

when rats were subjected to cerebral ischemia, their neurologic function was impaired, the protein expressions of klotho downregulated, the protein expressions of AQP4 and P38 MAPK increased, and the ratios of AQP4 and P-P38-positive area were significantly increased compared with the sham group rats. LV-KL-induced Klotho overexpression greatly improved neurobehavioral deficits and reduced infarct volume in MCAO rats. Klotho overexpression significantly reduced AQP4 and P38 MAPK pathway-related protein expression levels and the ratios of P-P38 and AQP4-positive area in MCAO rats. In addition, SB203580, a P38 MAPK signal pathway inhibitor, improved neurobehavioral deficits, reduced infarct volume, downregulated the expressions levels of AQP4 and P38 MAPK, and reduced the size of P-P38 and AQP4-positive area in MCAO rats.

CONCLUSION

Klotho could alleviate the infraction volume and neurological dysfunction in MCAO rats, and its mechanism may involve AQP4 expression downregulation by suppressing P38-MAPK activation.

Klotho's impact on diabetic nephropathy and its emerging connection to diabetic retinopathy

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease worldwide and is a significant burden on healthcare systems. α-klotho (klotho) is a protein known for its anti-aging properties and has been shown to delay the onset of age-related diseases. Soluble klotho is produced by cleavage of the full-length transmembrane protein by a disintegrin and metalloproteases, and it exerts various physiological effects by circulating throughout the body. In type 2 diabetes and its complications DN, a significant decrease in klotho expression has been observed. This reduction in klotho levels may indicate the progression of DN and suggest that klotho may be involved in multiple pathological mechanisms that contribute to the onset and development of DN. This article examines the potential of soluble klotho as a therapeutic agent for DN, with a focus on its ability to impact multiple pathways. These pathways include anti-inflammatory and oxidative stress, anti-fibrotic, endothelial protection, prevention of vascular calcification, regulation of metabolism, maintenance of calcium and phosphate homeostasis, and regulation of cell fate through modulation of autophagy, apoptosis, and pyroptosis pathways. Diabetic retinopathy shares similar pathological mechanisms with DN, and targeting klotho may offer new insights into the prevention and treatment of both conditions. Finally, this review assesses the potential of various drugs used in clinical practice to modulate klotho levels through different mechanisms and their potential to improve DN by impacting klotho levels.

Therapeutic effect and mechanism of combination therapy with ursolic acid and insulin on diabetic nephropathy in a type I diabetic rat model

This work aims to investigate the therapeutic effect of ursolic acid (UA) plus insulin (In) on diabetic nephropathy (DN) in streptozotocin (STZ)-induced T1DM rats. The experimental groups and operational details are as follows: A total of thirty-two SD rats were divided into four groups: the DN model group (DN, n = 8), DN + In treatment group (DN + In, n = 8), DN + In + UA administration group (DN + In + UA, n = 8), and negative control group (control, n = 8). After 8 weeks, changes in renal function indices and pathological damage were assessed. Additionally, oxidative stress-, apoptosis-, and fibrosis-related proteins in kidney tissue were measured. Compared with the control group, the vehicle group showed higher levels of creatine, blood urea nitrogen, urinary protein, apoptosis, and lipid peroxidation; lower superoxide dismutase levels; more severe levels of pathological kidney damage and renal fibrosis; and a deepened degree of EMT and EndMT. Better outcomes were achieved with the combined treatment than with insulin-only treatment. The improvement of TGF-β1, phosphorylated p38 MAPK, FGFR1, SIRT3 and DPP-4 expression levels in renal tissues after combination therapy was greater than that after insulin-only treatment. This study shows that the combination of insulin and UA significantly improved the pathological changes in the renal tissue of T1DM rats, and the underlying mechanism may be related to improving apoptosis and oxidative stress by regulating p38 MAPK, SIRT3, DPP-4 and FGFR1 levels, thereby blocking TGF-β signaling pathway activation and inhibiting EMT and EndMT processes.

Efficacy and safety of Abelmoschus moschatus capsules combined with tripterygium glycoside tablets on diabetic nephropathy: A systematic review and meta-analysis

Background: Diabetic nephropathy (DN) is one of the most serious chronic micro-vascular complications of diabetes and the leading cause of end-stage kidney disease (ESRD) worldwide, with reduced expectancy and quality of life and colossal financial and social burden worldwide. In spite of emerging treatments on DN, effective therapy on delaying the progression of DN is still lacking. In clinical practice, there are many studies focusing on Abelmoschus moschatus (AM) capsules together with Tripterygium glycoside (TG) tablets in the treatment of DN, and excellent results have been obtained.

Objective: The study aimed to evaluate the efficacy and safety of AM combined with TG in the treatment of DN.

Methods: Databases including PubMed, Web of Science, Cochrane Library, Embase, CNKI, WF, and VIP were searched from their inception to 1 March 2022. The “risk of bias” evaluation tool produced by the Cochrane Collaboration Handbook was used for evaluating the quality of the included studies. Revman 5.3 software was used for meta-analysis.

Results: Here, 11 studies with a total of 1,072 participants were included for this meta-analysis. Our results showed that AM combined with TG plus basic treatment could lower levels of 24 h-UP [MD = -0.18; 95% CI: (-0.21, -0.14); p < 0.00001], Scr [MD = -15.29; 95% CI: (-28.69, -1.88); p = 0.03], and BUN [MD = -1.18; 95% CI: (-1.69, -0.68); p < 0.00001]. Meanwhile, the adverse reaction rate increased in the combination group [RR = 1.88; 95% CI (1.26, 2.82); p = 0.002].

Conclusion: Current evidence suggests that AM combined with TG may be more effective in the treatment of DN, which will be highly beneficial to further theoretical discussion and practical clinical applications. However, the safety cannot be ignored because of nearly increasing 2-fold adverse events, although they can be mitigated through systematic treatment. Meanwhile, due to low quality of the included studies, great possibility of publication bias, and large heterogeneity among different studies, the results of our review should be evaluated with more prudence and high-quality RCTs are warranted to confirm this in the future.

Systematic review Registration:www.crd.york.ac.uk, identifier CRD42022344359.

Comparison of efficacy and safety of traditional Chinese patent medicines for diabetic nephropathy: A protocol for Bayesian network meta-analysis

BACKGROUND

Diabetic nephropathy (DN) is one of the most serious complications of diabetes. It has become a global public health problem among humans. DN is the leading cause of end-stage renal disease. At present, there is no specific medicine or modern medicinal therapy. In recent years, studies have shown that traditional Chinese patent medicines have been effective in treating DN, with few side effects. There is no systematic review on the treatment of DN with Chinese patent medicines. The current systematic review aims to evaluate the efficacy and safety of Chinese patent medicines for the treatment of DN.

METHODS

We will develop a search strategy to search major Chinese and English databases from inception to February 25, 2022 for randomized controlled trials examining the use of traditional Chinese patent medicine for the treatment of DN. The search will be conducted in accordance with the participants, interventions, comparisons, outcomes (PICOS) framework. Two researchers will use EndnoteX9 software to extract data and independently evaluate the quality of the included trials. Finally, the Bayesian network meta-analysis will be carried out by using software such as ReviewManager, Stata16.0, and WinBUGS1.4.3.

RESULTS

The primary outcomes will be urine albumin excretion rate, urea nitrogen, serum creatinine, total effective rate, and adverse events, and the secondary outcomes will be body mass index, fasting blood glucose, and 2-hPG during 75-g OGTT. These outcomes will be examined to provide a reliable basis for the treatment of DN with different traditional Chinese patent medicines.

CONCLUSION

This review will compare the efficacy and safety of different traditional Chinese patent medicines for treating DN. The results of the study will provide a basis for the selection of adjuvant treatment options for DN.

The effect of Chinese herbal formulas combined with metformin on modulating the gut microbiota in the amelioration of type 2 diabetes mellitus: A systematic review and meta-analysis

To assess and analyse the effectiveness and safety of combined Chinese herbal formula (CHF) and metformin treatment in the modulation of the gut microbiota in the amelioration of type 2 diabetes mellitus(T2DM), all publications addressing the effect of this combination treatment on the quantitative alterations in the gut microbiota and glucose parameters were collected. Rob tool in the Cochrane handbook was performed to evaluate the methodological quality of all included studies. Relevant information and statistics were abstracted and synthesized in Review Manager 5.4 to evaluate the efficacy of combination treatment. Sensitivity analyses and subgroup analyses were used to analyse the sources of heterogeneity. Publication bias analyses were performed by Stata software to assess the robustness and quality of the outcomes. As a result, a total of 12 eligible RCTs with 1307 T2DM participants from 7 electronic databases were included. Combined CHF with metformin treatment showed better efficacies than metformin monotherapy in regulating the structure of the gut microbiota, characterized by increased Bifidobacterium, Lactobacillus and Bacteroidetes and decreased Enterobacteriaceae, Enterococcus, and Saccharomyces along with better decreases in glycated haemoglobin, fasting plasma glucose, 2-hour postprandial blood glucose, fasting insulin and homeostasis model assessment of insulin resistance. Subgroup analyses further analysed the effect of metformin doses and CHF classifications on controlling hyperglycaemia and altering the gut microbiota. In conclusion, our meta-analysis suggested that combined CHF with metformin treatment is promising for the modulation of the gut microbiota along with ameliorating hyperglycemia in T2DM patients. Importantly, more well-designed RCTs are needed to validate the outcomes and verify the treatment value for clinical purposes.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021291524, identifier CRD42021291524.

Efficacy and safety of Huangkui capsule for diabetic nephropathy: A protocol for systematic review and meta-analysis

BACKGROUND

Diabetic nephropathy (DN) is 1 of the most serious complications of diabetes mellitus and the leading cause of end-stage renal disease in the world. Huangkui capsule, extracted from Abelmoschus manihot (L.) medic (AM), has been widely used to treat DN. However, there is no consensus on the efficacy of Huangkui capsule for DN. This study aims to perform meta-analysis to systematically review the efficacy and safety of Huangkui capsule.

METHODS

The following 9 electronic databases will be comprehensively searched: PubMed, web of science, MEDLINE, Embase, Cochrane Library, China National Knowledge Infrastructure, Chinese Scientific Journals Database, Wanfang data, and Chinese BioMedicine Literature Database. The retrieval time is from their inception to May 2021. According to the inclusion and exclusion criteria, 2 reviewers independently completed the study selection, data extraction, risk of bias assessment, and data synthesis. Review Manager Version 5.3 software will be used to conduct meta-analysis.

RESULTS

This study provides a high-quality synthesis to assess the efficacy of Huangkui capsule for treating diabetic nephropathy.

CONCLUSION

The result of this systematic review will provide objective evidence-based basis to judge the effectiveness and safety of Huangkui capsule on diabetic nephropathy.

Antiinflammatory Actions of Klotho: Implications for Therapy of Diabetic Nephropathy

Klotho was initially introduced as an antiaging molecule. Klotho deficiency significantly reduces lifespan, and its overexpression extends it and protects against various pathological phenotypes, especially renal disease. It was shown to regulate phosphate and calcium metabolism, protect against oxidative stress, downregulate apoptosis, and have antiinflammatory and antifibrotic properties. The course of diabetes mellitus and diabetic nephropathy resembles premature cellular senescence and causes the activation of various proinflammatory and profibrotic processes. Klotho was shown to exert many beneficial effects in these disorders. The expression of Klotho protein is downregulated in early stages of inflammation and diabetic nephropathy by proinflammatory factors. Therefore, its therapeutic effects are diminished in this disorder. Significantly lower urine levels of Klotho may serve as an early biomarker of renal involvement in diabetes mellitus. Recombinant Klotho administration and Klotho overexpression may have immunotherapeutic potential for the treatment of both diabetes and diabetic nephropathy. Therefore, the current manuscript aims to characterize immunopathologies occurring in diabetes and diabetic nephropathy, and tries to match them with antiinflammatory actions of Klotho. It also gives reasons for Klotho to be used in diagnostics and immunotherapy of these disorders.

Antidiabetic and Nephroprotective Effects of Polysaccharide Extract from the Seaweed Caulerpa racemosa in High Fructose-Streptozotocin Induced Diabetic Nephropathy

BACKGROUND

Nephropathy is a frontline complication of diabetes mellitus (DM) associated with impaired redox-inflammatory networks. The study investigated the antidiabetic and nephroprotective potentials of PCR against diabetic nephropathy (DN) in rats.

METHODS

DN was induced in rats using a combination of a high fructose solution for 4 weeks and an intraperitoneal injection of streptozotocin (35 mg/kg). Diabetic rats were treated with PCR (100 and 400 mg/kg body weight) for 8 weeks. Serum biochemical parameters as well as renal oxidative stress parameters, proinflammatory cytokines, Western blot and histopathological analyses were evaluated.

RESULTS

There were significant increases in fasting blood glucose, urinary albumin, serum creatinine, blood urea nitrogen (BUN), total cholesterol (TC), triglycerides (TG), and low-density lipoproteins (LDL-C) levels in diabetic rats compared to the non-diabetic control rats. DM-induced DN prominently depressed renal superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities, whereas renal malondialdehyde (MDA) level was markedly increased. Furthermore, renal inflammatory cytokines, IL-1β, IL-6, TNF-α and TGF-β, were considerably elevated compared to non-diabetic control rats. Additionally, DN rats showed a significant increase in renal fibrosis, as evidenced by increased expression of TGF-β1, collagen-1, fibronectin and alpha-smooth muscle actin (α-SMA) in the kidneys. Histopathological lesions were consistent with tubule thickening and glomerular hypertrophy. Conversely, PCR treatment exerted significant attenuation of hyperglycemia, dyslipidemia and renal oxidative stress indicators. The increased renal levels of IL-1β, IL-6, TNF-α and TGF-β were also notably reversed dose-dependently with alleviation of nephropathic histology. Furthermore, PCR reduced the expression of α-SMA, fibronectin, collagen-1 and TGF-β1 in the renal tissues.

CONCLUSION

Our results suggest that PCR displayed antidiabetic and nephroprotective effects against DN by impeding oxidative stress and inflammation. As such, PCR has potentials as a food supplement for alleviating renal dysfunction caused by diabetes.