Icariside II Attenuates Vascular Remodeling Via Wnt7b/CCND1 Axis.

ABSTRACT: Angioplasty often fails due to the abnormal proliferation of vascular smooth muscle cells (VSMCs). Success rates of angioplasty may increase following the administration of an agent that effectively ameliorates aberrant vascular remodeling. Icariside II (ICS-II) is a natural flavonol glycoside extract from the Chinese herbal medicine Epimedii that possesses several medicinal qualities that are beneficial in humans. Nevertheless, the role of ICS-II in addressing aberrant vascular remodeling have yet to be clarified. The current investigation studies the molecular effects of ICS-Ⅱ on balloon-inflicted neointimal hyperplasia in rats in vivo and on platelet-derived growth factor-induced vascular proliferation in primary rat aortic smooth muscle cells (VSMCs) in vitro. ICS-II was found to be as effective as rapamycin, the positive control used in this study. ICS-II inhibited neointimal formation in injured rat carotid arteries and notably reduced the expression of Wnt7b. ICS-Ⅱ significantly counteracted platelet-derived growth factor-induced VSMCs proliferation. Cell cycle analysis showed that ICS-II triggered cell cycle arrest during the G1/S transition. Western blot analysis further indicated that this cell cycle arrest was likely through Wnt7b suppression that led to CCND1 inhibition. In conclusion, our findings demonstrate that ICS-II possesses significant antiproliferative qualities that counteracts aberrant vascular neointimal hyperplasia. This phenomenon most likely occurs due to the suppression of the Wnt7b/CCND1 axis.

[Nitrogen and phosphorus dynamics along the primary succession in the Hailuogou Glacier retreat area, eastern Tibetan Plateau, China.] / 青藏高原东缘海螺沟冰川退缩区植被原生演替的氮磷动态.

In this study, seven sampling sites (glaciers retreated for 0, 10, 30, 40, 50, 80 and 127 years) were chosen along a primary succession sequence in the Hailuogou glacial retreat area in the eastern margin of the Tibetan Plateau, China. The accumulation and cycling characteristics of N and P under different succession stages were analyzed by measuring biomass and N and P contents in surface soil and each vegetation layer. The N and P contents in leaves, branches and roots of tree layers decreased along the succession sequence, whereas the N and P contents in stems were higher in the late succession stage. The changes of N and P contents in litter and soil O layer were consis-tent with those in the leaves and branches of tree layers. Ecosystem N and P storage increased along the succession sequence. Ecosystem N accumulation was mainly dependent on the vegetation layer in the early succession stage. After the community reached the climax, soil became the main N pool of the ecosystem. Vegetation P storage was higher than that in the surface soil after 80 years of glacial retreat. The nutrient accumulation rate in each layer of the ecosystem was rapid in the middle succession stage, with an order of surface soil > tree layer > understory vegetation layer. The nutrient cycling coefficients of N and P in broadleaved forest in the middle stage were higher than those in coniferous forest in the late stage, whereas the N and P utilization efficiency was lower than that in coniferous forest. Therefore, the mechanism of low nutrient cycling and high utilization efficiency of coniferous trees was conducive to the their competition with other species, thus finally forming the climax community.

Ginsenoside Re inhibits vascular neointimal hyperplasia in balloon-injured carotid arteries through activating the eNOS/NO/cGMP pathway in rats.

Ginsenoside Re (GS-Re) is one of the main ingredients of ginseng, a widely known Chinese traditional medicine, and has a variety of beneficial effects, including vasorelaxation, antioxidative, anti-inflammatory, and anticancer properties. The aims of the present study were to observe the effect of GS-Re on balloon injury-induced neointimal hyperplasia in the arteries and to investigate the mechanisms underlying this effect. A rat vascular neointimal hyperplasia model was generated by rubbing the endothelium of the common carotid artery (CCA) with a balloon, and GS-Re (12.5, 25 or 50 mg/kg/d) were subsequently continuously administered to the rats by gavage for 14 days. After GS-Re treatment, the vessel lumen of injured vessels showed significant increases in the GS-Re 25.0 and 50.0 mg/kg/d (intermediate- and high-dose) groups according to H.E. staining. Additionally, a reduced percentage of proliferating cell nuclear antigen (PCNA)-positive cells and an increased number of SM α-actin-positive cells were detected, and the levels of NO, cyclic guanosine monophosphate (cGMP), and eNOS mRNA as well as the phos-eNOSser1177/eNOS protein ratio were obviously upregulated in the intermediate- and high-dose groups. Moreover, the promotive effects of GS-Re on NO and eNOS expression were blocked by L-NAME treatment to different degrees. These results suggested that GS-Re can suppress balloon injury-induced vascular neointimal hyperplasia by inhibiting VSMC proliferation, which is closely related to the activation of the eNOS/NO/cGMP pathway.

Icariside II attenuates myocardial fibrosis by inhibiting nuclear factor-κB and the TGF-ß1/Smad2 signalling pathway in spontaneously hypertensive rats.

Studies have demonstrated that icariin plays important roles in preventing hypertension and improving myocardial hypertrophy, inflammatory and infiltration. Icariside (ICS II) is the main metabolite of icariin, which has anti-inflammatory and anti-oxidant activities and protects against ischaemic brain injury. Whether ICS II improves myocardial fibrosis in spontaneously hypertensive rats (SHRs) and the related mechanism remain unknown. Some studies have suggested that TGF-ß and the nuclear factor κB signalling pathway play a key role in the progression of myocardial fibrosis. Therefore, in the current study, we aimed to evaluate the effects of ICS II on induced myocardial fibrosis in SHRs and explore the mechanism underlying this activity. The SHRs were treated with ICS II (4, 8, and 16 mg/kg) via daily gavage for 12 weeks. Left ventricular function was detected using the Vevo2100 system, and the collagen area was measured by Masson staining. The results indicated that ICS II markedly improved left ventricular function and decreased the left ventricular myocardial collagen area compared with the SHR group. To further investigate the mechanism underlying this activity, we measured the protein expression of interleukin-1ß (IL-1ß), tumour necrosis factor-α (TNF-α), transforming growth factor-ß1 (TGF-ß1), Smad2, inhibitory κB (IκB), and nuclear factor κB (NF-κB) p65 by Western blot. The results showed that ICS II inhibited NF-κB p65 expression and the TGF-ß1/Smad2 signalling pathways. In conclusion, the present results suggest that ICS II suppresses myocardial fibrosis in SHRs, and this effect might be at least partially mediated through suppression of NF-kB signalling and the TGF-ß1/Smad2 signalling pathway.

Icariin Inhibits Pulmonary Hypertension Induced by Monocrotaline through Enhancement of NO/cGMP Signaling Pathway in Rats.

It has been reported that icariin (ICA) increased contents of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) by improving expression of endothelial nitric oxide synthase (eNOS) and inhibition of phosphodiesterase type 5 (PDE5). In addition, dysfunction of the NO/cGMP pathway may play a crucial role in the pathogenesis of pulmonary hypertension (PH). In this study, the potential protective effects of ICA on PH induced by monocrotaline (MCT, 50 mg/kg) singly subcutaneous injection were investigated and the possible mechanisms involved in NO/cGMP pathway were explored in male Sprague Dawley rats. The results showed that ICA (20, 40, and 80 mg/kg/d) treatment by intragastric administration could significantly ameliorate PH and upregulate the expression of eNOS gene and downregulate the expression of PDE5 gene in MCT-treated rats. Both ICA (40 mg/kg/d) and L-arginine (200 mg/kg/d), a precursor of NO as positive control, notably increased the contents of NO and cGMP in lung tissue homogenate, which were inversed by treatment with (N) G-nitro-L-arginine-methyl ester (L-NAME), a NOS inhibitor, and L-NAME-treatment could also inhibit the protective effects of ICA (40 mg/kg/d) on mean pulmonary artery pressure and artery remodeling and tends to inhibit right ventricle hypertrophy index. In summary, ICA is effective in protecting against MCT-induced PH in rats through enhancement of NO/cGMP signaling pathway in rats.

Inhibitory Effect of Ginsenoside Rg1 on Vascular Smooth Muscle Cell Proliferation Induced by PDGF-BB Is Involved in Nitric Oxide Formation.

Ginsenoside Rg1 (Rg1) has been reported to suppress the proliferation of vascular smooth muscle cells (VSMCs). This study aimed to observe the role of nitric oxide (NO) in Rg1-antiproliferative effect. VSMCs from the thoracic aorta of SD rats were cultured by tissue explant method, and the effect of Rg1 (20 mg·L(-1), 60 mg·L(-1), and 180 mg·L(-1)) on platelet-derived growth factor-BB (PDGF-BB)-induced proliferation was evaluated by MTT assay. The cell cycle was analyzed by flow cytometry. For probing the mechanisms, the content of NO in supernatant and cGMP level in VSMCs was measured by nitric oxide kit and cGMP radio-immunity kit, respectively; the expressions of protooncogene c-fos and endothelial NO synthase (eNOS) mRNA in the VSMCs were detected by real-time RT-PCR; the intracellular free calcium concentration ([Ca2(+)](i)) was detected with Fura-2/AM-loaded VSMCs. Comparing with that in normal group, Rg1 180 mg·L(-1) did not change the absorbance of MTT and cell percent of G(0)/G(1), G(2)/M, and S phase in normal cells (P > 0.05). Contrarily, PDGF-BB could increase the absorbance of MTT (P < 0.01) and the percent of the S phase cells but decrease the G(0)/G(1) phase cell percent in the cell cycle, accompanied with an upregulating c-fos mRNA expression (P < 0.01), which was reversed by additions of Rg1(20 mg·L(-1), 60 mg·L(-1), and 180 mg·L(-1)). Rg1 administration could also significantly increase the NO content in supernatant and the cGMP level in VSMCs, as well as the eNOS mRNA expression in the cells, in comparison of that in the group treated with PDGF-BB alone (P < 0.01). Furthermore, Rg1 caused a further increase in the elevated [Ca(2+)](i) induced by PDGF-BB. It was concluded that Rg1 could inhibit the VSMC proliferation induced by PDGF-BB through restricting the G(0)/G(1) phase to S-phase progression in cell cycle. The mechanisms may be related to the upregulation of eNOS mRNA and the increase of the formation of NO and cGMP.

Ginsenoside Rg1 inhibits vascular intimal hyperplasia in balloon-injured rat carotid artery by down-regulation of extracellular signal-regulated kinase 2.

ETHNOPHARMACOLOGICAL RELEVANCE: Ginsenoside Rg1 (Rg1) is one of the main active components of Panax ginseng a well-known herbal medicine. It has been demonstrated to inhibit proliferation of vascular smooth muscle cells (VSMCs) induced by tumor necrosis factor-αin vitro. The present study is aimed to examine the possible effects of Rg1 on vascular neointimal hyperplasia in balloon-injured carotid artery of rats in vivo. MATERIALS AND METHODS: The animal model was established by rubbing the endothelia with a balloon catheter in the common carotid artery (CCA) of male Sprague Dawley rats. Then the rats were intraperitoneally injected with distilled water in model group and sham operation control, or with Rg1 4, 8 and 16mg/kg/d in other balloon injured groups. After consecutive 14 days, the vascular intimal hyperplasia was evidenced by histopathological alterations of the CCA and by changes observed in the marker of the proliferation of VSMCs-the proliferating cell nuclear antigen (PCNA). The protein expressions of PCNA and the phosphorylated extracellular signal-regulated kinase2 (p-ERK2) as well as mitogen-ativated protein kinase phosphatase-1 (MKP-1) were examined by immunohistochemistry; while the expressions of proto-oncogene (c-fos), ERK2 and smooth muscle α-actin (SM α-actin) mRNA were analyzed by Real-Time RT-PCR. RESULTS: Rg1 administration could significantly ameliorate the histopathology of CCA and decrease the protein expression of PCNA induced by endothelia rubbing; and Rg1 medication also significantly decreased the expressions of p-ERK2 protein, ERK2 and c-fos mRNA in vessel wall, but up-regulated the MKP-1 expression, which was reported to inactivate mitogen-ativated protein kinase pathway. Furthermore, Rg1 could elevate the decreased SM α-actin mRNA expression induced by balloon injury. CONCLUSIONS: Rg1 can suppress the vascular neointimal hyperplasia induced by balloon injury, the mechanism may be involved in the inhibition on ERK2 signaling, and related, at least partly, to the increase in MKP-1 expression.

Total Ginsenosides suppress the neointimal hyperplasia of rat carotid artery induced by balloon injury.

Ginsenosides, the active components found in Panax ginseng, have been reported to inhibit the cardiac hypertrophy in rats. This study aims to observe the potential effect of total ginsenosides (TG) on the hypertrophic vascular diseases. The model of vascular neointimal hyperplasia was established by rubbing the endothelia of the common carotid artery with a balloon in male Sprague Dawley rats. TG (15 mg/kg/day, 45 mg/kg/day), L-arginine (L-arg) 200 mg/kg/day, and NG-nitro-L-arginine-methyl ester (L-NAME) 100 mg/kg/day used with the same dose of L-arg or TG 45 mg/kg/day were given for 7 and 14 consecutive days after surgery. TG and L-arg administrations significantly ameliorated the histopathology of injured carotid artery, which was abolished or blunted by L-NAME, an NOS inhibitor; TG and L-arg could also remarkably reduce the expression of proliferating cell nuclear antigen (PCNA), a proliferation marker of vascular smooth muscle cells(VSMCs), in neointima of the injured artery wall. Further study indicated that balloon injury caused a decreased superoxide dismutase (SOD) activity and an elevated malondialdehyde (MDA) content in plasma, and reduced the cGMP level in the artery wall, which were reversed by TG. It was concluded that TG suppress the rat carotid artery neointimal hyperplasia induced by balloon injury, which may be involved in its anti-oxidative action and enhancing the inhibition effects of NO/cGMP on VSMC proliferation.