阿魏酸钠经RhoA和Rho-kinase信号通路抑制小鼠肝纤维化的机制研究

目的:探讨阿魏酸钠对于四氯化碳诱导的小鼠肝纤维化的抑制机制。方法:将CL级昆明属小鼠随机分为正常对照组、CCl4-花生油模型组(模型组)、阿魏酸钠给药组(给药组),每组20只。模型组小鼠和给药组小鼠分别给予CCl4-花生油(1∶1,V/V)1ml/kg灌胃,正常对照组小鼠给予同等剂量生理盐水,三组均为1次/d,连续8周;从第9周开始,给药组小鼠给予阿魏酸钠20mg/kg灌胃,1次/d,连续给药4周。12周后,检测各组小鼠肝功能水平、肝影像学指标、病理变化及肝脏中RhoA、Rho-kinase的总体情况。结果:通过正常对照组、模型组及给药组的小鼠肝功能和肝纤维化指标等指标对比,发现阿魏酸钠能显著抑制小鼠肝纤维化程度。结论:阿魏酸钠可能通过调节RhoA和Rho-kinase信号通路抑制小鼠肝纤维化。

基于Rho/Rho-kinase信号通路探讨丙泊酚减轻大鼠脑缺血再灌注损伤的效果

目的基于Rho/Rho-kinase信号通路探讨丙泊酚减轻大鼠脑缺血再灌注损伤的效果。方法 SD大鼠100只分成:对照组、模型组、丙泊酚低、中、高剂量组(20.0、40.0、80.0 mg/kg),模型组、丙泊酚低、中、高剂量组建立脑缺血再灌注损伤模型,建模成功后,丙泊酚低、中、高剂量组给予相应剂量丙泊酚灌胃,对照组和模型组给予等体积生理盐水,持续给予4周,实验结束后,对每只大鼠进行神经功能缺损评分,行贴纸去除及平衡木行走实验,对大鼠海马区进行病理评分,同时测定大鼠脑组织中Rho、Rho-kinase mRNA和蛋白水平。结果模型组神经功能缺损评分、双侧贴纸去除时间、平衡木过杆时间、海马组织病理评分、脑组织海马区Rho、Rho-kinase mRNA和蛋白表达水平明显高于对照组(P<0.05);丙泊酚各剂量组神经功能缺损评分、双侧贴纸去除时间、平衡木过杆时间、海马组织病理评分、脑组织海马区Rho、Rho-kinase mRNA和蛋白表达水平明显低于模型组(P<0.05);且随着丙泊酚给药剂量的增加,神经功能缺损评分、双侧贴纸去除时间、平衡木过杆时间、海马组织病理评分、脑组织海马区Rho、Rho-kinase mRNA和蛋白表达水平逐渐降低,剂量-效应关系明显(P<0.05)。对照组海马区神经元细胞完整,排列紧密;模型组海马区神经元排列松散,细胞深染固缩,有片状坏死,神经细胞间质隔离;丙泊酚高剂组神经元细胞趋于正常;丙泊酚中、低剂量组较模型组而言,神经细胞疏松、固缩程度轻,神经元细胞核仁清楚可见。结论丙泊酚能减轻大鼠脑缺血再灌注神经功能损伤;其机制与丙泊酚能抑制Rho、Rho-kinase mRNA和蛋白的表达进而抑制Rho/Rho-kinase信号通路的激活有关。

Rho/Rho-kinase通路在低氧性肺动脉高压发病中作用的研究进展

低氧性肺动脉高压(HPH)是指由低氧血症引起的肺动脉压力升高,以肺血管收缩、肺血管重塑、右心室肥厚、右心衰竭为特征。Rho/Rho-kinase通路可通过调节胞质内Ca^(2+)浓度促进肺部血管收缩,通过调节肺动脉平滑肌细胞增殖与调亡促进肺血管重塑,且参与右心结构、功能改变,在HPH发病过程中发挥重要作用。

The role of Rho/Rho-kinase pathway and the neuroprotective effects of fasudil in chronic cerebral ischemia

The Rho/Rho-kinase signaling pathway plays an important role in cerebral ischemia/reperfusion injury. However, very few studies have examined in detail the changes in the Rho/Rho-kinase signaling pathway in chronic cerebral ischemia. In this study, rat models of chronic cerebral ischemia were established by permanent bilateral common carotid artery occlusion and intra- gastrically administered 9 mg/kg fasudil, a powerful ROCK inhibitor, for 9 weeks. Morris water maze results showed that cognitive impairment progressively worsened as the cerebral ischemia proceeded. Immunohistochemistry, semi-quantitative RT-PCR and western blot analysis showed that the expression levels of Rho-kinase, its substrate myosin-binding subunit, and its relat- ed protein alpha smooth muscle actin, significantly increased after chronic cerebral ischemia. TUNEL staining showed that chronic cerebral ischemia could lead to an increase in neuronal apoptosis, as well as the expression level of caspase-3 in the frontal cortex of rats subjected to chronic cerebral ischemia. Fasudil treatment alleviated the cognitive impairment in rats with chronic cerebral ischemia, and decreased the expression level of Rho-kinase, myosin-binding subunit and alpha smooth muscle actin. Furthermore, fasudil could regulate cerebral injury by reducing cell apoptosis and decreasing caspase-3 expression in the frontal cortex. These findings demonstrate that fasudil can protect against cognitive impairment induced by chronic cerebral ischemia via the Rho/Rho-kinase signaling pathway and anti-apoptosis mechanism.

Effect of Rho-kinase pathway on neurite outgrowth of rat hippocampal neurons under atomic force microscopy

Hippocampal neurons of neonatal rats were cultured in serum-free culture medium for 5 days in vitro, and treated with the Rho-kinase inducer lysophosphatidic acid. Atomic force microscopy revealed that the numbers of level-1, -2 and -3 neurites protruding from rat hippocampal neurons was significantly reduced. After treatment with the Rho kinase inhibitor Y27632, a significant increase in the numbers of these neurites was observed. Our experimental findings indicate that the Rho-kinase pathway is closely associated with the neurites of hippocampal neurons.

A Rho-kinase Inhibitor, Fasudil, Attenuates Progressive Glomerulosclerosis Induced by Daunorubicin in Rats

Accumulating evidence suggests that the small G protein Rho and its downstream effec-tor Rho kinase may play important roles in kidney biology. The present study examined the effects of a Rho-kinase inhibitor, fasudil, on daunorubicin-induced progressive glomerulosclerosis and explored the underlying mechanism by which fasudil ameliorates glomerulosclerosis. Thirty-six male SD rats were randomly allocated into sham-operation group （sham group, n=12）, unilateral nephrectomy （UNX）＋daunorubicin （DRB） group （model group, n=12）, UNX＋DRB＋Fasudil group （treatment group, n=12）. Two to four weeks after the establishment of the animal model, 6 rats in each group were taken randomly for the detection of 24-h urine protein excretion. Kidney sections were exam-ined by HE and PAS staining, immunohistochemistry and transmission electric microscopy （TEM）. The expression of Rho-kinase mRNA and P27 mRNA in kidney were detected by RT-PCR. It was found that the 24-h urine protein excretion in model group was increased significantly as compared with sham group （P〈0.01）. But this increase was significantly suppressed by fasudil （P〈0.05）. At 4 week, the foot process effacement in podocytes, mesangial proliferation and ECM accumulation were observed in model group, presenting as focal segmental glomerulosclerosis. But in the treatment group, the fasudil alleviated glomerular injury, with proliferating cell nuclear antigen （PCNA）-positive cell infiltration ameliorated and the expression of P27 increased. The expression of Rho-kinase mRNA was significantly enhanced in model group and was suppressed in treatment group. Moreover, fasudil up-regulated the mRNA expression of P27. Our study demonstrated that the glomerulosclerosis was substantially ameliorated by inhibiting the expression of Rho-kinase. It is suggested that Rho-kinase pathway is involved in the renal injury and the inhibition of Rho-kinase may constitute a therapeutic strategy for the treatment of renal injury.

Atorvastatin attenuates involvement of RhoA/Rho-kinase pathway and NF-κB activation in hypoxic pulmonary hypertensive rats

Background Hypoxic pulmonary hypertension （HPH） contributes to the pathogenesis of cardiopulmonary diseases.Several lines of evidence indicate that the Rho A/Rho-kinase pathway play an important role in the progress of pulmonary hypertension.Stains have been shown exert numerous biological effects that are independent of their cholesterollowering property.We hypothesized that the Rho A/Rho-kinase pathway is involved in the pathogenesis of HPH,and that atorvastatin would attenuate involvement of the Rho A/Rho-kinase pathway in a HPH rat model.Methods Thirty-two Wistar rats were randomly divided into four groups：control group,hypoxic group,atovastatin group,and normal saline group.The control group was kept in a normoxia environment.The other groups were exposed to hypoxia for three weeks.Atovastatin was administered daily via a gastric gavage in the atovastatin group.We measured the mean pulmonary arterial pressure （mPAP）,the ratio of the right ventricular weight to the sum of the weights of the left heart ventricle and septum （RV/（LV＋S））,arteriole wall thickness/vascular external diameter （WT％）,vascular area/total vascular area （WA％）,expression of RhoA and phos-MYPT-1 protein in lung tissue,and NF-κB activation in pulmonary vascular smooth muscle cells.Results Compared with the control group,mPAP,RV/（LV＋S）,WT％,WA％,NF-κB activation,expression of RhoA,and phos-MYPT-1 were increased in the hypoxic and normal saline groups （P ＜0.05）.Compared with the hypoxic group,mPAP,RV/（LV＋S）,WT％,WA％,NF-κB activation,expression of RhoA,and phos-MYPT-1 were decreased in the atovastatin group （P ＜0.05）.Correlations between phos-MPTY-1 and mPAP,WA％,WT％,and NF-κB activation were all positive.Conclusions The Rho NRho-kinase pathway plays an important role in the development of HPH.Atorvastatin reversed HPH by inhibiting the activity of Rho A/Rho-kinase and NF-κB.

Differential effects of Rho-kinase inhibitor and angiotensin Ⅱ type-1 receptor antagonist on the vascular function in hypertensive rats induced by chronic L-NAME treatment

Little attention has been paid to the effect of Rho-kinase inhibitor on the vascular dysfunction of nitric oxide-deficient hypertension.We aimed to investigate whether the Rho-kinase inhibitor fasudil showed beneficial effect on the vascular dysfunction of the N^(G)-nitro-L-arginine methyl ester(L-NAME)treated rat,as well as to compare the differential effects of fasudil and angiotensin Ⅱ receptor antagonist valsartan on vascular function.In the present study,both valsartan and fasudil exerted antihypertensive action on the L-NAME-treated rats,while only va lsartan attenuated the cardiac hypertrophy.Treatment with valsartan showed improvement on vascular reactivity to norepinephrine,KCl and CaCl_(2),whereas fasudil therapy showed little effect on vasoconstriction.Endothelium-dependent vasodilation to acetylcholine was reduced in the NO-deficient group but was normalized by the fasudil therapy.The increased expression of RhoA and Rho-kinase(ROCK)in the vasculature was corrected well to normal level by either valsartan or fasudil administration,which seemed to be at least partially responsi ble for the beneficial effect of the drug infusion.These findings suggest that the angiotensin Ⅱ receptor antagonist interferes more with the contractile response than Rho-kinase inhibitor,whereas inhibition of Rho-kinase activity exhibits a better improvement on vasorelaxation than blockade of angiotensin Ⅱ receptor.

Role of estrogen receptor β selective agonist in ameliorating portal hypertension in rats with CCl4-induced liver cirrhosis

AIM: To investigate the role of diarylpropionitrile(DPN), a selective agonist of estrogen receptor β(ERβ), in liver cirrhosis with portal hypertension(PHT) and isolated hepatic stellate cells(HSCs).METHODS: Female Sprague-Dawley rats were ovariectomized(OVX), and liver cirrhosis with PHT was induced by CCl4 injection. DPN and PHTPP, the selective ERβ agonist and antagonist, were used as drug interventions. Liver fibrosis was assessed by hematoxylin and eosin(HE) and Masson's trichrome staining and by analyzing smooth muscle actin expression. Hemodynamic parameters were determined in vivo using colored microspheres technique. Protein expression and phosphorylation were determined by immunohistochemical staining and Western blot analysis. Messenger RNA levels were analyzed by quantitative real-time polymerase chain reaction(q RT-PCR). Collagengel contraction assay was performed using gel lattices containing HSCs treated with DPN, PHTPP, or Y-27632 prior to ET-1 addition. RESULTS: Treatment with DPN in vivo greatly lowered portal pressure and improved hemodynamic parameters without affecting mean arterial pressure, which was associated with the attenuation of liver fibrosis and intrahepatic vascular resistance(IHVR). In CCl4-treated rat livers, DPN significantly decreased the expression of Rho A and ROCK Ⅱ, and even suppressed ROCK Ⅱ activity. Moreover, DPN remarkedly increased the levels of endothelial nitric oxide synthase(e NOS) and phosphorylated e NOS, and promoted the activities of protein kinase G(PKG), which is an NO effector in the liver. Furthermore, DPN reduced the contractility of activated HSCs in the 3-dimensional stress-relaxed collagen lattices, and decreased the ROCK Ⅱ activity in activated HSCs. Finally, in vivo /in vitro experiments demonstrated that MLC activity was inhibited by DPN.CONCLUSION: For OVX rats with liver cirrhosis, DPN suppressed liver Rho A/ROCK signal, facilitated NO/PKG pathways, and decreased IHVR, giving rise to reduced portal pressure. Therefore, DPN represents a relevant treatment choice against PHT in cirrhotic patients, especially postmenopausal women.

Current advances in the understanding of coronary vasospasm

Recent years have witnessed progress in our understanding of coronary vasospasm(CVS).It is evident that this is not only an East Asian but also a global disease associated with significant symptoms and possible lethal sequelae for afflicted individuals.A correct diagnosis depends on the understanding of pathogenesis and symptomatology of CVS.With the correct diagnosis,we can manage CVS patients effectively and promptly,providing optimal patient safety.Advances in our understanding of interactions between inflammation,endothelium,and smooth muscle cells have led to substantial progress in understanding the pathogenesis of symptoms in CVS and have provided some insights into the basic etiology of this disorder in some patient subpopulations.We look forward to a time when therapy will address pathophysiology and perhaps,even the primary etiology.

奥扎格雷钠对脑梗死大鼠的治疗作用研究

目的:研究奥扎格雷钠治疗对脑梗死大鼠的疗效及可能的作用机制。方法:SPF级SD健康雄性大鼠30只,随机分为假手术组、模型组和奥扎格雷钠组,各10只。模型组和奥扎格雷钠组构建脑梗死模型,奥扎格雷钠组腹腔注射奥扎格雷钠(2 mg/kg),其余2组注射等量生理盐水。比较各组神经功能评分、脑梗死体积、Rho/Rho-kinase信号通路相关蛋白表达。结果:奥扎格雷钠组脑梗死体积、神经功能评分均低于模型组,差异有统计学意义(P<0.05)。与假手术组比较,模型组和奥扎格雷钠组eNOS蛋白表达降低,RhoA、MLCP、p-MYPT-1蛋白表达升高,差异均有统计学意义(P<0.05);与模型组比较,奥扎格雷钠组eNOS蛋白表达升高,RhoA、MLCP、p-MYPT-1蛋白表达降低,差异均有统计学意义(P<0.05)。结论:奥扎格雷钠可能通过调控Rho/Rho-kinase信号通路相关因子,促进脑梗死大鼠神经功能恢复。

Threonine 532 phosphorylation in CIC-3 is required for angiotensin II-induced Cl- current and migration in cultured vascular smooth muscle cells

Aim Angiotensin II （AngII） induces vascular smooth muscle cell （VSMC） migration and growth, which is responsible for vascular remodeling during some cardiovascular diseases. It has been demonstrated to activate a C1 current, but the underlying mechanism is not clear. Methods Whole-cell patch clamp, co-immunoprecipitation （co-IP）, site-specific mutagenesis, angiotensinII-infusion hypertensive mice model were used. Results In VSMCs, AngII could induce a C1C-3-dependent C1- current that was abolished in C1C-3 null mice. The activation mechanism of this AngII-induced C1- current was ascribed to the interaction between C1C-3 and Rho-kinase 2 （ROCIL2）, as re- vealed by N-terminal or C-terminal truncation of C1C-3, ROCIC2 siRNA and Co-IP experiments. Then we searched for and identified the phosphorylation site of C1C-3 at threonine 532 is critical for AngII-induced C1- current and VSMC migration through ROCK. The C1C-3 T532D mutant （mutation of threonine 532 to aspartate）, mimicking the phos- phorylation state of C1C-3, significantly potentiated AngII-induced C1- current and VSMC migration; while C1C-3 T532A （mutation of threonine 532 to alanine） had the opposite effects. Furthermore, we found a remarkably de- creased AngII-induced VSMC migration in C1C-3 null mice that is insensitive to Y27632, an inhibitor of ROCIL2. In addition, AngII-induced cerebrovascular remodeling was ameliorated in C1C-3 null mice, possibly by ROCIL2 path- way. Conclusions C1C-3 protein phosphorylation at threonine 532 by ROCIL2 is required for AngII-induced C1- cur- rent and VSMC migration that are involved in AngII-induced hypertensive vascular remodeling.

Synthesis and Stability of Hydroxyfasudil Derivatives as Prodrugs

Fasudil(HA-1077) is the first small-molecule inhibitor of Rho-kinase and has been employed for clinical treatment of cerebral vasospasm.Hydroxyfasudil,as a metabolite of fasudil,exhibited better activity than fasudil.However,it also suffered from quick metabolisation,weak lipotropy and worse penetration of the blood-brain barrier.Thus,some hydroxyfasudil derivatives such as hydroxyfasudil acetate,hydroxyfasudil phosphate and 1-methoxyfasudil as the prodrugs of hydroxyfasudil were designed and synthesised.Meanwhile,the stability of these three compounds was also investigated.Furthermore,the reason and mechanism of hydrolysis of these compounds were discussed.This work could provide a useful guide for future research.

Fasudil inhibits platelet-derived growth factor-induced human pulmonary artery smooth muscle cell proliferation by up-regulation of p27^kipl via the ERK signal pathway

Background RhoA/ Rho kinase （ROCK） pathway is involved in pulmonary arterial hypertension （PAH） and pulmonary artery smooth muscle cell （PASMC） proliferation. Inhibition of ROCK has been proposed as a treatment for PAH. But the mechanism of RhoA/ROCK pathway and its downstream signaling in proliferation of human PASMCs is unclear. We investigated the effect of fasudil, a selective ROCK inhibitor, on platelet-derived growth factor （PDGF） induced human PASMC proliferation, and the possible association between RhoA/ROCK and extracellular signal-regulated kinase （ERK）,p27KiP1.Methods Human PASMCs were cultured with the stimulation of 10 ng/ml PDGF, and different concentrations of fasudil were added before the addition of mitogen. Cell viability and cell cycle were determined with MTT and flow cytometry respectively. ROCK activity, ERK activity and protein expression of proliferating cell nuclear angigen （PCNA） and p27Kip1 were measured by immunoblotting.Results By MTT assay, PDGF significantly increased the OD value that represented human PASMC proliferation, and pretreatment with fasudil significantly reversed this effect in a dose-dependent manner. After PDGF stimulation, the percentage of cells in S phase increased dramatically from 15.6% to 24.3%, while the percentage in G0/G1 phase was reduced from 80.6% to 59%. And pretreatment with fasudil reversed the cell cycle effect of PDGF significantly in a dose-dependent manner. PDGF markedly induced ROCK activity and ERK activity with a peak at 15 minutes, which were significantly inhibited by fasudil. In addition, fasudil significantly inhibited PDGF-induced PCNA expression and fasudil also upregulated p27Kip1 expression in human PASMCs, which decreased after PDGF stimulation.Conclusion RhoA/ROCK is vital for PDFG-induced human PASMC proliferation, and fasudil effectively inhibited PDGF-induced human PASMC proliferation by up-regulation of p27Kip1, which may be associated with inhibition of ERK activity.

Fluvastatin attenuates myocardial interstitial fibrosis and cardiac dysfunction in diabetic rats by inhibiting over-expression of connective tissue growth factor

Background Diabetic myocardiopathy is characterized by myocardial interstitial fibrosis and cardiac dysfunction. Statins were found to exert protective effects on cardiovascular disease by suppressing activation of small G proteins, independently of their lipid-lowering effect. The study investigated the effect of fluvastatin on myocardial interstitial fibrosis, cardiac function and mechanism of its action in diabetic rats. Methods Twenty-four male SD rats were randomly assigned to 3 groups： control rats （n=-8）, streptozotocin （STZ）-induced diabetic rats （n=8）, and diabetic rats treated with fluvastatin （administered fluvastatin orally, 10 mg/kg body weight per day, n=-8）. Twelve weeks later, miniature cardiac catheter was inserted into the left ventricle to conduct hemodynamic examination. Then myocardium tissues were collected, collagen content was detected by picro-sirius red staining, real-time quantitative reverse transcription polymerase chain reaction （RT-PCR） was used to detect the mRNA expression of connective tissue growth factor （CTGF）, and Western blotting was used to detect the protein expression of CTGF. Rho activity was determined by pull-down assay. Results After 12 weeks, the left ventricular systolic pressure （LVSP） and maximum rate of left ventricular （LV） pressure rise and fall （＋dP/dt max and -dP/dt max） were significantly lower and left ventricular end diastolic pressure （LVEDP） was higher in the diabetic rats than those in the control rats （P 〈0.01）. Moreover, in LV myocardial tissue of diabetic rats the collagen content, fibronectin, mRNA and protein expression of CTGF and the activity of RhoA were all significantly increased compared with the control rats （P 〈0.01）. Administration of fluvastain obviously improved the cardiac function of diabetic rats, attenuated fibronectin expression, mRNA and protein expression of CTGF and the activity of RhoA in LV myocardium of diabetic rats. Conclusions Fluvastatin attenuates cardiac dysfunction and myocardial interstitial fibrosis of diabetic rat by inhibiting activity of RhoA to down-regulate the overexpression of CTGF, and Rho/Rho-kinase pathway may be an important target in the treatment of diabetic cardiomyopathy.

Downregulation of Rho associated coiled-coil forming protein kinase 1 in the process of delayed myocardialization of cardiac proximal outflow tract septum in connexin 43 knockout mice embryo

Background The connexin43 knockout （Cx43 KO） mouse dies at birth with an enlarged conotruncal region, which leads to the obstruction of the right outflow tract （OFT）. Since myocardialization of the proximal OFT septum is one of the key events during heart development, we investigated the process in the Cx43 KO embryo hearts. Rho associated coiled-coil forming protein kinase 1 （ROCK1）, is a recently found key molecule to regulate the myocardialization of OFT, but its spatiotemporal expression pattern during myocardialization remains unknown. The objective of this study was to investigate the differentially expressed pattern of ROCK1 between Cx43 KO and wild type embryo hearts, and its relationship with the delayed myocardialization in Cx43 KO embryo hearts. Methods Using immunohistochemistry, the processes of myocardiolization were investigated both in Cx43 KO and wild type embryo hearts. The differentially expressed pattern of ROCK1 between Cx43 KO and wildtype embryo hearts was evaluated both at the mRNA and protein level by real-time RT-PCR and immunohistochemistry. Results The expression of α-sarcomeric actin （α-SCA） in the proximal OFT septum of Cx43 KO embryos was delayed. Meanwhile, it was shown that the downregulation of ROCK1 coincided with delayed myocardialization. The expression of ROCK1 protein was mainly limited to the proximal outflow tract septum from embryo day （E） Ell.5 to E15.5. Its expression pattern was similar with that of α-SCA. Real-time RT-PCR found that the expression level of Rock-1 mRNA began at a low level on Ell .5 and reached peak at E13.5 and E14.5. Conclusions ROCK1 may have an important role in the process of myocardialization of the proximal OFT septum. Downregulation of ROCK1 is likely to contribute to the aberrant myocardialization in Cx43 KO embryo hearts.