Effect of Shenkang on renal fibrosis and activation of renal interstitial fibroblasts through the JAK2/STAT3 pathway.

BACKGROUND: Activation of renal fibroblasts is a critical mechanism in the process of renal fibrosis. As a commonly used herbal formula, Shenkang (SK) has been found to attenuate renal fibrosis and renal parenchyma destruction. However, the effect of SK on renal fibroblast activation in unilateral ureteral obstruction (UUO) mice and its molecular mechanism remain undetermined. The present study was performed to elucidate the effect of SK on renal fibroblast activation and renal fibrosis, as well as the potential underlying mechanism, in both NRK-49F cells and UUO mice. METHODS: NRK-49F cells were stimulated with 10 ng/ml TGF-ß1 for 48 h. After SK treatment, the CCK-8 method was used to evaluate cell viability. Thirty-six C57BL/6 mice were randomly divided into the sham group, UUO group, angiotensin receptor blocker (ARB) group, and SK high-, moderate- and low-dose groups. UUO was induced in mice except those in the sham group. Drugs were administered 1 day later. On the 13th day, the fractional anisotropy (FA) value was determined by MRI to evaluate the degree of renal fibrosis. After 14 days, serum indexes were assessed. Hematoxylin and eosin (HE) and Sirius red staining were used to observe pathological morphology and the degree of fibrosis of the affected kidney. Western blotting and PCR were used to assess the expression of related molecules in both cells and animals at the protein and gene levels. RESULTS: Our results showed that SK reduced extracellular matrix (ECM) and α-smooth muscle actin (α-SMA) expression both in vitro and in vivo and attenuated renal fibrosis and the pathological lesion degree after UUO, suppressing JAK2/STAT3 activation. Furthermore, we found that SK regulated the JAK2/STAT3 pathway regulators peroxiredoxin 5 (Prdx5) in vitro and suppressor of cytokine signaling protein 1 (SOCS1) and SOCS3 in vivo. CONCLUSIONS: These results indicated that SK inhibited fibroblast activation by regulating the JAK2/STAT3 pathway, which may be a mechanism underlying its protective action in renal fibrosis.

Renoprotective effect of vasopressin v2 receptor antagonist tolvaptan in Dahl rats with end-stage heart failure.

Tolvaptan is a highly selective and orally effective arginine vasopressin V2 receptor antagonist, and is potentially useful for the treatment of heart failure (HF) patients. However, the renoprotective effect of long-term tolvaptan therapy and its underlying mechanisms remain unknown. We evaluated the effects of chronic treatment with tolvaptan on renal dysfunction, podocyte injury, inflammation, oxidative stress, Rho-kinase, epithelial-mesenchymal transition (EMT), and the extracellular signal-regulated protein kinase (ERK1/2) pathway in the renal cortex of Dahl salt-sensitive hypertensive (DS) rats with end-stage severe HF. DS and Dahl salt-resistant rats were fed a high-salt diet at 6 weeks of age. DS rats were treated with vehicle and tolvaptan (0.05% concentration in diet) from the age of 11 to 18 weeks. Vehicle-treated DS rats developed proteinuria, renal dysfunction, glomerulosclerosis, and interstitial fibrosis, which were ameliorated by tolvaptan without changing blood pressure. Decreased expression of nephrin and podocin and increased desmin-positive area in failing rats were restored by tolvaptan. Upregulation of NAD(P)H oxidase p22(phox), p47(phox), and gp91(phox), EMT markers such as transforming growth factor-ß1, vimentin, and fibronectin expression, and Rho-kinase and ERK1/2 phosphorylation in DS rats were significantly suppressed by tolvaptan. Tolvaptan administration resulted in significant inhibition of tumor necrosis factor-α and monocyte chemoattractant protein-1 expression, and nuclear factor-κB phosphorylation. We concluded that long-term tolvaptan therapy may improve renal dysfunction, glomerulosclerosis, podocyte injury, and inflammation associated with oxidative stress, as well as EMT, ERK, and the Rho-kinase pathway in the failing heart of DS rats. Thus, tolvaptan may be a therapeutic strategy for end-stage severe HF.

[Experimental study on effect of Kangxianling on rat renal interstitial fibrosis].

OBJECTIVE: To study the effect and mechanism of Kangxianling (KXL, a TCM herbal compound) on renal interstitial fibrosis induced by unilateral ureteral obstruction (UUO). METHODS: Eighteen male SD rats were randomly divided into 3 groups, 6 in each group, the sham operated group, the model group, and the KXL group. Renal interstitial fibrosis model was established in rats by UUO. After rats were raised for additional 14 days, their body weight, serum levels of creatinine (SCr) and blood urea nitrogen (BUN) were analyzed. Then rats were sacrificed, their renal pathology examined by HE staining and PASM staining; expressions of transforming growth factor-beta1 (TGF-beta1), hepatocyte growth factor (HGF) mRNA, and a-smooth muscle actin (alpha-SMA), TGF-beta1 receptor I (TbetaR I), TGF-beta1 receptor II (TbetaR II) and hepatocyte growth factor receptor (C-Met) protein in kidney tissue were determined by RT-PCR and Western blotting respectively. RESULTS: SCr and BUN in the model group were significantly higher than those in the sham operated group (P <0.05). Expressions of TGF-beta1 mRNA and a-SMA, TbetaR I , TbetaR II and C-Met protein in kidney tissue in the model group significantly up-regulated and mRNA expression of HGF significantly down-regulated, and obvious hyperplasia of the base member of glomeruli was seen. After intervention with KXL, BUN content significantly lowered, alpha-SMA, TbetaR I and TbetaR II protein expression decreased and HGF mRNA expression up-regulated significantly in the treated group, with slight pathological changes only shown as mild hyperplasia of the base member of glomeruli and renal tubules. CONCLUSION: KXL could inhibit the protein expressions of a-SMA, TbetaR I , TbetaR II and increase the mRNA expression of HGF, which is a protective factor against renal fibrosis. Therefore, it is effective in alleviating the renal interstitial fibrosis and improving the renal function in UUO rats.

[Effect of Kangxianling Decoction on expression of hepatocyte growth factor mRNA and phosphorylations of extracellular signal-regulated protein kinase 1/2 and p38 in renal tissue of rats with unilateral ureteral obstruction].

OBJECTIVE: To study the effect of Kangxianling Decoction (KXLD), a compound traditional Chinese herbal medicine, on expression of hepatocyte growth factor (HGF) mRNA and phosphorylations of extracellular signal-regulated protein kinase 1/2 (ERK 1/2) and p38 in renal tissue of rats with unilateral ureteral obstruction (UUO). METHODS: Eighteen male SD rats were randomly divided into 3 groups: sham-operated group, untreated group and KXLD-treated group. A rat model of renal interstitial fibrosis was established by UUO. Rats with UUO were sacrificed after intragastric administration of KXLD for 14 days, and the parameters such as serum creatinine (SCr), blood urea nitrogen (BUN) and hydroxyproline in the kidney of rats in 3 groups were analyzed. The expression of HGF mRNA in kidney tissue was determined by reverse transcription polymerase chain reaction. The expressions of c-Met protein, ERK1/2 protein, p38 protein and the phosphorylations of ERK1/2 and p38 were determined by Western blotting method. RESULTS: The levels of SCr, BUN and hydroxyproline in the untreated group were significantly increased as compared with those in the sham-operated group (P<0.05). The expression of HGF mRNA in the untreated group was significantly down-regulated. The expression of c-Met protein and the phosphorylations of ERK1/2 and p38 in the kidney tissue of rats with UUO in the untreated group were significantly up-regulated. After intervention with KXLD, the phosphorylations of ERK1/2 and p38 were all significantly inhibited except for c-Met expression. The HGF mRNA was increased in KXLD-treated group. CONCLUSION: KXLD can decrease the level of collagen in the obstructed kidney of rats with UUO and alleviate the renal interstitial fibrosis in rats with UUO through enhancing the HGF mRNA expression and inhibiting the phosphorylations of ERK1/2 and p38.

Demographic, pathologic, and toxicological profiles of 127 decedents testing positive for ephedrine alkaloids.

The relative toxicity of ephedra-containing dietary supplements is disputed. In order to ascertain the magnitude of the problem, we reviewed all autopsies in our Medical Examiner's jurisdiction, from 1994 to 2001, where ephedrine or any its isomers (E+) were detected. Toxicology testing results were tabulated and anatomic findings in E+ cases were compared to those in a control group of drug-free trauma victims. Of 127 E+ cases identified, 33 were due to trauma. Decedents were mostly male (80.3%) and mostly Caucasian (59%). Blood ephedrine concentrations were <0.49 mg/l in 50% of the cases, range 0.07-11.73 mg/l in trauma victims, and 0.02-12.35 mg/l in non-trauma cases. Norephedrine (NE) was present in the blood of 22.8% (mean of 1.81 mg/l, S.D.=3.14 mg/l) and in the urine of 36.2% (mean of 15.6 mg/l, S.D.=21.50mg/l). Pseudoephedrine (PE) was present in the blood of 6.3% (8/127). More than 88% (113/127) of the decedents also tested positive for other drugs, the most common being cocaine (or its metabolites) and morphine. The most frequent pathologic diagnoses were hepatic steatosis (27/127) and nephrosclerosis (22/127). Left ventricular hypertrophy was common, and coronary artery disease (CAD) detected in nearly one third of the cases. The most common findings in E+ deaths are those generally associated with chronic stimulant abuse, and abuse of other drugs was common in those with CAD. There were no cases of heat stroke or rhabdomyolysis. In most cases, norephedrine was not detected, suggesting it plays no role in ephedrine toxicity.

Hypertensive nephrosclerosis in the Dahl/Rapp rat. Initial sites of injury and effect of dietary L-arginine supplementation.

BACKGROUND: The Dahl/Rapp strains of salt-sensitive (SS/Jr) and salt-resistant (SR/Jr) rat were developed to examine pathogenetic mechanisms that produce hypertension in response to an increase in dietary salt. We have shown that providing SS/Jr rats with L-arginine, the metabolic precursor of nitric oxide, acutely prevented salt-sensitive hypertension, suggesting that SS/Jr rats developed hypertension because of inadequate nitric oxide production while on a high-salt diet. EXPERIMENTAL DESIGN: Male 23-day SS/Jr and SR/Jr rats were placed on chow that contained 8% sodium chloride. One group of SS/Jr rats also received L-arginine, 1.25 g/liter, in their drinking water. These three groups were examined at weekly intervals for 4 weeks. RESULTS: SS/Jr rats rapidly developed hypertension when placed on the high-salt chow. After 2 weeks on this diet, inulin clearance dramatically decreased, and albumin excretion rate increased. By the fourth week of study, SS/Jr rats on the high-salt diet had died or were dying. Coincident with the progressive decline in inulin clearance, renal morphologic analysis confirmed development of myointimal thickening, fibrinoid necrosis, and glomerulosclerosis. In contrast, over the 4 weeks of study, SS/Jr rats supplemented with oral L-arginine did not develop hypertension and any of the associated renal complications seen in age-matched SS/Jr rats on the high-salt diet. L-Arginine also corrected hypertension in SS/Jr rats exposed to the high-salt chow for 2 weeks before the inception of L-arginine. L-Arginine administration after 3 weeks on this chow, however, failed to reverse hypertension and the depressed inulin clearance and morphologic renal damage. CONCLUSIONS: Along with previous work (Chen PY, Sanders PW, J Clin Invest 88:1559-67), these studies were consistent with the hypothesis that hypertension and hypertensive nephrosclerosis developed in SS/Jr rats because, while on a high-salt diet, substrate (L-arginine) became a rate-limiting factor in the synthesis of nitric oxide.