Huangkui capsule attenuates renal fibrosis in diabetic nephropathy rats through regulating oxidative stress and p38MAPK/Akt pathways, compared to α-lipoic acid.

In traditional Chinese medicine (TCM), Abelmoschus manihot (L.) medic (AM) is a natural medicinal plant used for the treatment of inflammatory diseases. Recently, Huangkui capsule (HKC), a Chinese patent medicine extracted from AM, has been widely applied to the clinical therapy of renal fibrosis in patients with early diabetic nephropathy (DN). However, the therapeutic mechanisms involved in vivo remain ambiguous. The goal of this study is to expound the mechanism in vivo of HKC in order to deepen the understanding of its clinical effects, by using the approaches of contrasting the dose-effects of HKC on oxidative stress (OS) in the kidney compared to α-lipoic acid (LA), and then demonstrating whether and how anti-oxidative properties of HKC or LA might be beneficial for the treatment of renal fibrosis in vivo. Thirty-three rats were divided into 5 groups, a Sham group, a Vehicle group, a L-HKC group, a H-HKC group and a LA group. The different doses of HKC, LA and distilled water were daily administrated for 8 weeks after the induction of DN by the unilateral nephrectomy combined with streptozotocin (STZ) intraperitoneal injections. Rat's general status, biochemical parameters, renal histological changes and OS indicators, as well as the key protein expressions in p38 mitogen-activated protein kinase (p38MAPK)/serine-threonine kinase (Akt) signaling pathways and downstream cytokines including transforming growth factor (TGF)-β1 and tumor necrosis factor (TNF)-α were examined, respectively. HKC and LA ameliorated body weight, kidney weight, urinary albumin and renal function including blood urea nitrogen and serum uric acid, attenuated renal fibrosis including the cell numbers and extracellular matrix rate in glomerulus, and controlled OS indicators including malondialdehyde, total superoxide dismutase, 8-hydroxy-2'-deoxyguanosine and nicotinamide adenine dinucleotide phosphate oxidase 4, but did not lower blood glucose in DN model rats. Among them, the anti-renal fibrosis effect of H-HKC was better than that of LA. In addition, HKC simultaneously down-regulated the protein expressions of phosphorylated p38MAPK, phosphorylated Akt (p-Akt), TGF-β1 and TNF-α in the kidney of DN model rats, unlike HKC, LA only down-regulated p-Akt and TNF-α protein expressions. We have demonstrated that HKC, similar to LA, is renoprotective via attenuating OS and renal fibrosis in the DN rat model. The potential mechanisms by which HKC and LA exert their therapeutic effects in vivo are respectively through down-regulating the activation of p38MAPK and/or Akt pathways as well as the expressions of TGF-β1 and/or TNF-α in the kidney. Our findings thus provide the useful information about a clinical combination of HKC and LA in early DN patients.

Mao ZM ，Shen SM ，Wan YG ，Sun W ，Chen HL ，Huang MM ，Yang JJ ，Wu W ，Tang HT ，Tang RM ... -  《-》

[Effects and mechanisms of huangkui capsule ameliorating renal fibrosis in diabetic nephropathy rats via inhibiting oxidative stress and p38MAPK signaling pathway activity in kidney].

Mao ZM ，Wan YG ，Sun W ，Chen HL ，Huang YR ，Shi XM ，Yao J ... -  《-》

Huangkui capsule, an extract from Abelmoschus manihot (L.) medic, ameliorates adriamycin-induced renal inflammation and glomerular injury via inhibiting p38MAPK signaling pathway activity in rats.

Abelmoschus manihot (L.) medic (AM) is a natural medicinal plant used for the treatment of inflammatory diseases in China. Huangkui capsule (HKC), an extract from AM, has been proved clinically effective in improving renal inflammation and glomerular injury in chronic kidney disease (CKD). However, the dose-effects and the mechanisms involved in vivo are still unclear. This study was performed to examine the dose-effects of HKC on renal inflammation and glomerular lesion in adriamycin-induced nephropathy (ADRN), then to clarify the mechanisms in vivo of HKC by investigating its actions on modulating the activation of p38 mitogen-activated protein kinase (p38MAPK) signaling pathway. The rats with chronic ADRN, created by the unilateral nephrectomy and twice adriamycin injections (ADR, 4 mg/kg and 2mg/kg) within 4 weeks, were divided into four groups, a Sham group, a Vehicle group, a high-dose HKC group, and a low-dose HKC group, and that, sacrificed at the end of the 4th week after the administration. The rat's general status, renal morphological appearance, proteinuria, blood biochemical parameters, glomerular morphological changes, podocyte shape, and macrophage (ED1(+) and ED3(+) cells) infiltration in glomeruli were examined, respectively. The protein expressions of inflammatory cytokines including tumor necrosis factor (TNF)-α and interleukin (IL)-2, as well as p38MAPK signaling molecules such as transforming growth factor (TGF)-β1, p38MAPK, and phosphorylated-p38MAPK (p-p38MAPK), were also evaluated individually. HKC at high dose of 2g/kg/d not only significantly ameliorated the rat's general status, renal morphological appearance, proteinuria, albumin, and glomerulosclerosis, but also obviously reduced the infiltrated ED1(+) and ED3(+) macrophages in glomeruli and TNF-α protein expression in the kidney, in addition to these, evidently down-regulated TGF-β1 and p-p38MAPK protein expressions in ADRN rats, but had no influence on podocyte shape and renal function. HKC could dose-dependently ameliorate renal inflammation and glomerular injury in ADRN rats, by way of reducing the infiltration and the activation of macrophages in glomeruli, and TNF-α protein expression in the kidney, as well as inhibiting p38MAPK signaling pathway activity via the down-regulation of p-p38MAPK and TGF-β1 protein expressions in vivo.

Tu Y ，Sun W ，Wan YG ，Che XY ，Pu HP ，Yin XJ ，Chen HL ，Meng XJ ，Huang YR ，Shi XM ... -  《-》

Huangkui capsule, an extract from Abelmoschus manihot (L.) medic, improves diabetic nephropathy via activating peroxisome proliferator-activated receptor (PPAR)-α/γ and attenuating endoplasmic reticulum stress in rats.

Abelmoschus manihot (L.) medic (AM) is a natural medicinal plant used for the treatment of chronic kidney disease (CKD) in China. Huangkui capsule (HKC), an extract from AM, has been proved clinically effective in improving renal inflammation and glomerular injury in CKD. However, the mechanisms of HKC are still not fully understood. Peroxisome proliferator-activated receptor (PPAR)-α/γ dual agonists have the potential to be used as therapeutic agents for the treatment of type 2 diabetes and diabetic nephropathy (DN). This study evaluated the function of Huangkui capsule (HKC), an extract from Abelmoschus manihot (L.) medic (AM), as a dual agonist for PPARα/γ and investigated its anti-DN effects in a DN rat model. ChIP and reporter gene assays were performed and the expression of PPARα/γ target genes was monitored to examine the ability of HKC to activate PPARα/γ. DN was induced in male Sprague-Dawley rats via unilateral nephrectomy and intraperitoneal injection of streptozotocin. HKC was administered to the diabetic nephropathy rats at three different doses: high dose HKC (300mg/kg/d); middle dose HKC (175mg/kg/d); and low dose HKC (75mg/kg/d). Irbesartan (4mg/kg/d body weight) was used as a positive control. Following 12 weeks' treatment, we measured general status, renal morphological appearance, proteinuria, blood biochemical parameters, and glomerular morphological changes. The expression of collagen IV, TGFβ, TNFα and IL-6 in renal tissue was evaluated. Endoplasmic reticulum (ER) stress in renal tissue was also analyzed. HKC enhanced the transcriptional activity of PPARα and PPARγ in cultured cells, livers and kidneys of DN rats, and it reduced serum triglyceride and cholesterol levels and fat in livers of DN rats. Furthermore, HKC reduced the expressions of inflammatory genes in kidneys of DN rats. Strikingly, HKC reduced ER stress and c-Jun NH2-terminal kinase activation in the liver and kidney of DN rats and subsequently improved renal injury. Our results show that HKC improved lipid metabolic disorders by activating PPARα/γ and attenuating ER stress. HKC could dose-dependently ameliorate renal inflammation and glomerular injury in DN rats. These results suggest that HKC has potential as an anti-DN agent for the treatment of DN in humans.

Ge J ，Miao JJ ，Sun XY ，Yu JY ... -  《-》

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

Huangkui capsule (HKC), extracted from Abelmoschus manihot (L.) medic (AM), as a patent proprietary Chinese medicine on the market for approximately 20 years, has been clinically used to treat chronic glomerulonephritis. Renal fibrosis has been implicated in the onset and development of diabetic nephropathy (DN). However, the potential application of HKC for preventing DN has not been evaluated. This study was designed to investigate the efficacy and underlying mechanisms of HKC combined with metformin (MET), the first-line medication for treating type 2 diabetes, in the treatment of renal interstitial fibrosis. A rat model of diabetes-associated renal fibrosis was established by intraperitoneal injection of streptozotocin (STZ, 65 mg/kg) combined with a high-fat and high-glucose diet. The rats were randomly divided into five groups: normal control, DN, HKC (1.0 g/kg/day), MET (100 mg/kg/d), and HKC plus MET (1.0 g/kg/day + 100 mg/kg/d). Following drug administration for 8 weeks, we collected blood, urine, and kidney tissue for analysis. Biochemical markers and metabolic parameters were detected using commercial kits. Histopathological staining was performed to monitor morphological changes in the rat kidney. High-glucose-induced human kidney HK-2 cells were used to evaluate the renal protective effects of HKC combined with MET (100 μg/mL+10 mmol/L). MTT assay and acridine orange/ethidium bromide were used to examine cell proliferation inhibition rates and apoptosis. Immunofluorescence assay and Western blot analysis were performed to detect renal fibrosis-related proteins including Klotho, TGF-β1, and phosphorylated (p)-p38. Combination therapy (HKC plus MET) significantly improved the weight, reduced blood glucose (BG), blood urea nitrogen (BUN), total cholesterol (T-CHO), triglycerides (TG), low-density lipoprotein (LDL) and increased the level of high-density lipoprotein (HDL) of DN rats. Combination therapy also significantly reduced urine serum creatinine (SCR) and urine protein (UP) levels as well as reduced the degrees of renal tubule damage and glomerulopathy in DN rats. Combination therapy ameliorated renal fibrosis, as evidenced by reduced levels of alpha-smooth muscle actin and fibronectin and increased expression of E-cadherin in the kidneys. Moreover, HKC plus MET alleviated the degree of DN in part via the Klotho/TGF-β1/p38MAPK signaling pathway. In vitro experiments showed that combination therapy significantly inhibited cell proliferation and apoptosis and regulated fibrosis-related proteins in high-glucose (HG)-induced HK-2 cells. Further studies revealed that combination therapy suppressed cell proliferation and fibrosis by inhibiting the Klotho-dependent TGF-β1/p38MAPK pathway. HKC plus MET in combination suppressed abnormal renal cell proliferation and fibrosis by inhibiting the Klotho-dependent TGF-β1/p38MAPK pathway. Collectively, HKC combined with MET effectively improved DN by inhibiting renal fibrosis-associated proteins and blocking the Klotho/TGF-β1/p38MAPK signaling pathway. These findings improve the understanding of the pathogenesis of diabetes-associated complications and support that HKC plus MET combination therapy is a promising strategy for preventing DN.

Gu LY ，Yun-Sun ，Tang HT ，Xu ZX ... -  《-》