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
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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
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