Effects and mechanisms of Shenkang injection promoting extracellular matrix degradation via regulating ERK1/2/MMPs signaling pathway in renal failure rats / 中国中药杂志

This study aimed to clarify preliminarily the effects and mechanisms of Shenkang injection (SKI) promoting extracellular matrix(ECM)degradation via regulating extracellular-signal regulated protein kinase(ERK)1/2/matrix metalloproteinases(MMPs)signaling pathway in renal failure rats. Twenty rats were randomly divided into 4 groups：the Sham group,the Model group,the SKI group and the Enalapril maleate(EM)group. The model rats with renal failure were induced by intragastric administration of adenine and unilateral ureteral obstruction(UUO). After modeling, the rats in SKI group and EM group were intervened by intraperitoneal injection of SKI or intragastric administration of the EM suspension,while the rats in Sham group and Model group were administrated with distilled water respectively for 3 weeks. The 24 h urinary protein excretion(Upro)and urinary N-acety1-β-D-glucosaminidase(UNAG)in all rats were tested after drug administration. All rats were sacrificed after drug administration for 3 weeks,blood and kidney were collected,renal morphological characteristics were observed. Furthermore,serum biochemical indices and the protein expressions of collagen type IV(CIV),MMP-2,MMP-9,tissue inhibitors of metalloproteinase(TIMP)-1,ERK1/2 and phosphorylated-ERK1/2(p-ERK1/2)in the kidney were evaluated respectively. The results indicated that,after the intervention of SKI,serum creatinine(Scr),blood urea nitrogen(BUN),uric acid(UA),albumin(Alb),Upro,UNAG and renal morphological change in model rats were improved at different levels,respectively. Moreover,these actions were similar to EM. In addition to these,SKI adjusted the protein expressions of MMP-2,MMP-9 and TIMP-1,and down-regulated the protein expressions of p-ERK1/2 in the kidney. Moreover,these actions were different from EM. In conclusion,SKI promotes ECM degradation and delays the progression of renal failure possibly through regulating ERK1/2 signaling pathway activation in the kidney and intervening MMPs/TIMP-1 expressions in vivo.

Puerarin attenuates PM2.5-induced vascular endothelial cells injury via ERK1/2 signaling pathway / 中国中药杂志

To investigate the effect and the mechanism of puerarin in attenuating PM2.5-induced human umbilical vein endothelial cells (EA.hy926) injury, the samples of fine particulate matter (PM2.5) were collected and made into suspension. Different concentrations of PM2.5 (0,20, 200, 400 mg•L⁻¹) were used to contaminate EA.hy926 cells for 24 h. The cells survival rate was detected by MTT assay; cells apoptosis of EA.hy926cells was detected by flow cytometry; the protein levels of p-ERK1/2, Bax and Bcl-2 were detected by Western blot; the contents of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), malonaldehyde (MDA), and the activities of superoxide dismutase (SOD) and lactic dehydrogenase (LDH) were measured by ELISA. Puerarin at different concentrations (10, 50, 100 μmol•L⁻¹) or a specific inhibitor of ERK1/2 pathway PD98059 (20 μmol•L-1) was added into the EA.hy926 cells to observe the intervention effect and mechanism of puerarin. Compared with the control group, PM2.5 reduced the cells survival rate, up-regulatedp-ERK1/2 protein level and Bax/Bcl-2 ratio in a dose dependent manner to promote apoptosis; increased the contents of TNF-α, IL-6 and MDA, the activity of LDH, but decreased SOD activity in the EA.hy926 cells (P<0.05). Compared with PM2.5 group, puerarin increased the cells survival rate, down-regulated p-ERK1/2 protein level and Bax/Bcl-2 ratio in a dose dependent manner to inhibit the apoptosis; decreased the contents of TNF-α, IL-6 and MDA, the activity of LDH, but increased SOD activity in the EA.hy926 cells (P<0.05). The results indicated that puerarin could attenuate PM2.5-induced EA.hy926 cells injury via the inhibition of ERK1/2 pathway.

Protective effect of emilia sonchifolia on rats with experimental hepatic steatosis and its molecular mechanism / 中国中西医结合急救杂志

Objective To investigate the preventive effects of emilia sonchifolia on experimental hepatic steatosis in rats and its molecular mechanism.Methods Seventy Sprague-Dawley (SD) rats were randomly divided into five groups: normal control, model, high dose emilia sonchifolia, low dose emilia sonchifolia groups and high dose emilia sonchifolia + phosphorylated extracellular signal regulated protein kinase 1/2 (pERK1/2) inhibitor (PD98059) group (PD group). In normal control group, the rats were fed with normal diet, and in the other four groups, the rats were fed with high fat and low protein diet combined with 30% carbon tetrachloride (CCl4) peanut oil 2 mL/kg subcutaneous injection, once every 3 days for consecutive 3 weeks to establish animal models with hepatic steatosis. In emilia sonchifolia high and low dose groups, 5.0 g/kg and 2.5 g/kg doses of emilia sonchifolia were given respectively by gavage, once a day. In PD group, after administration of emilia sonchifolia high dose by gavage once a day, additionally PD98059 0.3 mg/kg was injected through a tail vein, once a week. After 3 weeks, all rats were switched to normal diet and treatment continued as before. At the end of the 5th week, liver tissues were taken for pathological analyses. The serum levels of alanine transaminase (ALT), aspartate transaminase (AST), total cholesterol (TC), and triglyceride (TG) were determinated by automatic biochenical analyzer. The positive cell count and protein expressions of sterol-regulatory element binding protein 1 (SREBP-1), pERK1/2, toll like receptor 4 (TLR4) and high mobility group box-1 protein (HMGB1) were tested by immunohistochemistry, Western Blot and flow cytometry. The levels of superoxide dismutase (SOD) and malonaldehyde (MDA) in liver cell homogenate were detected by hydroxylamine and TBA method.Results Compared with the model group, the lobular inflammation in high and low dose emilia sonchifolia groups and PD group was attenuated (1.50±0.53, 1.80±0.43, 1.20±0.42 vs. 2.30±0.48), and ALT, AST, TC, TG, SREBP-1, and MDA were significantly decreased, the decrease in high dose emilia sonchifolia group being the most significant [ALT (U/L): 51.91±6.95 vs. 66.50±12.15, AST (U/L): 125.70±5.62 vs. 147.10±10.52, TC (mmol/L): 1.79±1.04 vs. 2.81±1.08, TG (mmol/L): 0.87±0.55 vs. 1.17±0.67, SREBP-1: (30.60±5.56)% vs. (53.10±5.02)%, MDA (nmol/mg): 5.20±0.87 vs. 10.61±5.45,P 0.05]. While the above index values in PD group were close to those in high dose emilia sonchifolia group, showing that PD98059 had no impact on emilia sonchifolia's action.Conclusions Emilia sonchifolia can alleviate hepatic injury and attenuate lobular inflammation in rat experimental hepatic steatosis. Its mechanism is possibly related to the reduction of oxidative stress reaction, and SREBP-1 may be as a mediator involved in the action.

Prostaglandin E2 receptor 1 antagonist attenuates mesangial cell lesion induced by TGF-β1 in mice through inhibiting ERK signal pathway / 中华肾脏病杂志

Objective To explore the effects and mechanisms of prostaglandin E2 (PGE2) receptor 1 antagonist (SC-19220) on proliferation,prostaglandin synthase and extracellular regulated protein kinases (ERK) signal pathway induced by transforming growth factor β1(TGF-β1) in glomerular mesangial cells.Methods Mouse glomerular mesangial cells (GMCs) were divided into 5 groups:control group,TGF-β1 (10 μg/L) group,TGF-β1 (10 μg/L) plus SC-19220 group (0.1,0.5,1.0 μmol/L).The proliferation of GMCs was measured by CCK-8.The PGE2 in supernatant was measured by ELISA.The expression of connective tissue growth factor (CTGF),laminin (LN),cyclooxygenase 2(COX2),membrane-bound prostaglandin E2 synthase 1 (mPGES1) protein and mRNA was examined by Westem blotting and real-time quantitative PCR,ERK1/2 or phospho-ERK1/2 was measured by Western blotting as well.Results TGF-β1 induced the proliferation of GMCs and increased the secretion of PGE2.Besides,TGF-β1 significantly up-regulated the expression of CTGF,LN,COX2 and mPGES1 mRNA and protein (P ＜ 0.05),and increased the expression of phospho-ERK1/2 protein (P ＜ 0.05).However,SC-19220 significantly attenuated the changes of above-mentioned parameters and their activities (P ＜ 0.05).All the effects of SC-19220 were in dose-dependent manner.Conclusions SC19220 may reduce TGF-β1-induced cell damage by suppressing the activity of ERK1/2,and feedback inhibition of COX2,mPGES1 and PGE2,thus decreases the expression of LN and CTGF.

Expression characteristics of phosphorylated forms of mitogen-activated protein kinases in hypertrophic scars / 解放军医学杂志

Objective To study expression intensity and distribution of phosphorylated forms of extracellular signal-regulated protein kinase1/2 (ERK1/2), stress-activated protein kinase (SAPK) and P38MAPK in normal skin and hypertrophic scars and their potential biological significance. Methods The morphological characteristics of hypertrophic scars in different periods after wound healing and normal skin were examined histopathologically. Protein expression of p-ERK1/2, p-SAPK and p-P38MAPK was also assessed with immunohistochemical technique. Results In normal skin, phosphorylated forms of ERK1/2, SAPK and P38MAPK were mainly located in epidermal basal cells, in which the positive cellular rates of all the three proteins were low. Along with the maturation of hypertrophic scars, protein contents of p-ERK1/2 and p-SAPK were progressively increased. In mature hypertrophic scars, positive signals of these two proteins were mostly distributed in keratinocytes and some fibroblasts. The positive cellular rate of p-P38MAPK ascended in active hypertrophic scar, then decreased to a level which was still higher than that of normal skin. Conclusion The formation of hypertrophic scars may be associated with the alteration in signaling pathways which results in the increment of protein contents of p-ERK1/2, p-SAPK and p-P38MAPK.