Clonal integration of stress signal induces morphological and physiological response of root within clonal network.

Clonal integration of defense or stress signal induced systemic resistance in leaf of interconnected ramets. However, similar effects of stress signal in root are poorly understood within clonal network. Clonal fragments of Centella asiaticas with first-young, second-mature, third-old and fourth-oldest ramets were used to investigate transportation or sharing of stress signal among interconnected ramets suffering from low water availability. Compared with control, oxidative stress in root of the first-young, second-mature and third-old ramets was significantly alleviated by exogenous ABA application to the fourth-oldest ramets as well as enhancement of antioxidant enzyme (SOD, POD, CAT and APX) activities and osmoregulation ability. Surface area and volume in root of the first-young ramets were significantly increased and total length in root of the third-old ramets was significantly decreased. POD activity in root of the fourth-oldest and third-old ramets was significantly enhanced by exogenous ABA application to the first-young ramets. Meanwhile, total length and surface area in root of the fourth-oldest and third-old ramets were significantly decreased. Ratio of belowground to aboveground biomass in the whole clonal fragments was significantly increased by exogenous ABA application to the fourth-oldest or first-young ramets. It is suggested that transportation or sharing of stress signal may induce systemic resistance in root of interconnected ramets. Specially, transportation or sharing of stress signal against phloem flow was observed in the experiment. Possible explanation is that rapid recovery of foliar photosynthesis in first-young ramets subjected to exogenous ABA application can partially reverse phloem flow within clonal network. Thus, our experiment provides insight into ecological implication on clonal integration of stress signal.

20(R)-ginsenoside Rg3 attenuates cerebral ischemia-reperfusion injury by mitigating mitochondrial oxidative stress via the Nrf2/HO-1 signaling pathway.

Reducing mitochondrial oxidative stress has become an important strategy to prevent neuronal death in ischemic stroke. Previous studies have shown that 20(R)-ginsenoside Rg3 can significantly improve behavioral abnormalities, reduce infarct size, and decrease the number of apoptotic neurons in cerebral ischemia/reperfusion injury rats. However, it remains unclear whether 20(R)-ginsenoside Rg3 can inhibit mitochondrial oxidative stress in ischemic stroke and the potential molecular mechanism. In this study, we found that 20(R)-ginsenoside Rg3 notably inhibited mitochondrial oxidative stress in middle cerebral artery occlusion/reperfusion (MCAO/R) rats and maintained the stability of mitochondrial structure and function. Treatment with 20(R)-ginsenoside Rg3 also decreased the levels of mitochondrial fission proteins (Drp1 and Fis1) and increased the levels of fusion proteins (Opa1, Mfn1, and Mfn2) in MCAO/R rats. Furthermore, we found that 20(R)-ginsenoside Rg3 promoted nuclear aggregation of nuclear factor erythroid2-related factor 2 (Nrf2) but did not affect Kelch-like ECH-associated protein-1 (Keap1), resulting in the downstream expression of antioxidants. In in vitro oxygen-glucose deprivation/reperfusion stroke models, the results of PC12 cells treated with 20(R)-ginsenoside Rg3 were consistent with animal experiments. After transfection with Nrf2 short interfering RNA (siRNA), the protective effect of 20(R)-ginsenoside Rg3 on PC12 cells was reversed. In conclusion, the inhibition of mitochondrial oxidative stress plays a vital position in the anti-cerebral ischemia-reperfusion injury of 20(R)-ginsenoside Rg3, and its neuroprotective mechanism is related to the activation of the nuclear factor erythroid2-related factor 2/heme oxygenase 1 signaling pathway.

Effects of nutrient supply on leaf stoichiometry and relative growth rate of three stoloniferous alien plants.

Different nutrient supply brings about changes in leaf stoichiometry, which may affect growth rate and primary production of plants. Invasion of alien plants is a severe threat to biodiversity and ecosystem worldwide. A pot experiment was conducted by using three stoloniferous alien plants Wedelia trilobata, Alternanther philoxeroides and Hydrocotyle vulgaris to investigate effects of nutrient supply on their leaf stoichiometry and relative growth rate. Different nitrogen or phosphorus supply was applied in the experiment (N1:1 mmol L-1, N2:4 mmol L-1, and N3:8 mmol L-1, P1:0.15 mmol L-1, P2:0.6 mmol L-1 and P3:1.2 mmol L-1). Nitrogen and phosphorus concentrations in leaves of the three alien plants significantly increased with increase of nitrogen supply. With increase of phosphorus supply, nitrogen or phosphorus concentration of leaf was complex among the three alien plants. N:P ratio in leaf of the three alien plants subjected to different levels of nutrient supply was various. A positive correlation between relative growth rate and N:P ratio of the leaf is observed in W. trilobata and A. philoxeroides suffering from N-limitation. A similar pattern was not observed in Hydrocotyle vulgaris. We tentatively concluded that correlations between relative growth rate and N: P ratio of the leaf could be affected by species as well as nutrient supply. It is suggested that human activities, invasive history, local abundance of species et al maybe play an important role in the invasion of alien plants as well as relative growth rate.

Geraniin Protects against Cerebral Ischemia/Reperfusion Injury by Suppressing Oxidative Stress and Neuronal Apoptosis via Regulation of the Nrf2/HO-1 Pathway.

Geraniin, a polyphenol isolated from Phyllanthus amarus, possesses extensive biological and pharmaceutical activities. In this study, we investigated the protective effect against cerebral ischemia/reperfusion (I/R) injury of geraniin and explored its potential mechanism. Middle cerebral artery occlusion/reperfusion (MCAO/R) was used to simulate cerebral I/R injury in vivo, and oxygen-glucose deprivation/reoxygenation (OGD/R) was applied to establish an in vitro model of cerebral I/R injury. In this study, we performed TTC and HE staining and adopted a neurological score method to evaluate the neuroprotective effect of geraniin in vivo and used the CCK-8 assay to assess this effect in vitro. Indices of reactive oxidation capacity were measured in vivo and in vitro to verify the antioxidant capacity of geraniin. TUNEL staining and flow cytometry were applied to measure the apoptosis rate, and Western blotting was performed to assess the expression of apoptosis-related proteins. Finally, the expression of Nrf2 and HO-1 was evaluated in vivo and in vitro by Western blotting. Geraniin significantly reduced the infarct volume, decreased neurological deficit scores, alleviated pathological changes in neurons, and increased the cell survival rate. Geraniin increased the activity of superoxide dismutase (SOD) and decreased the activity of lactate dehydrogenase (LDH) and the contents of malondialdehyde (MDA), nitric oxide (NO), and neuronal nitric oxide synthase (nNOS) in vivo and in vitro. In addition, geraniin significantly reduced the apoptosis. Furthermore, geraniin also evidently increased Nrf2 (total and nuclear) and HO-1 protein expression in vivo and in vitro. Collectively, these results imply that geraniin may exert a protective effect against cerebral I/R injury by suppressing oxidative stress and neuronal apoptosis. The mechanism underlying the protective effect of geraniin is associated with activation of the Nrf2/HO-1 pathway. Our results indicate that geraniin may be a potential drug candidate for the treatment of ischemic stroke.

Antiatherosclerotic effects of corilagin via suppression of the LOX-1/MyD88/NF-κB signaling pathway in vivo and in vitro.

Corilagin, a natural polyphenol compound isolated from Phyllanthus urinaria L., exerts various pharmacological effects, such as antihyperglycemic, antitumor, and antioxidative stress properties, but the mechanisms underlying the antiatherosclerotic effects of corilagin have not been entirely elucidated. In the present study, we investigated the antiatherosclerotic effects of corilagin using a high-fat diet (HFD)-induced atherosclerotic rabbit model and ox-LDL-induced vascular smooth muscle cells (VSMCs) and explored the underlying molecular mechanisms. The serum lipid levels were measured through an enzymatic colorimetric assay. A histological analysis of rabbit aortas was performed after hematoxylin-eosin and oil red O staining. The proliferation of ox-LDL-induced VSMCs was detected using MTT assays, and the migration of cells was determined by wound scratch assays. In addition, the mRNA and protein expression levels of lectin-like ox-LDL receptor-1 (LOX-1), myeloid differentiation factor 88 (MyD88), nuclear factor-kappa B (NF-κB), monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor α (TNF-α) were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting assays. Our results indicate that corilagin significantly reduced the serum levels of TC, TG and LDL-C, increased the HDL-C levels, decreased the intimal thickening in the thoracic aorta, and reduced the formation of foam cells in an HFD-induced rabbit atherosclerosis model. Moreover, corilagin suppressed the proliferation and migration of ox-LDL-induced VSMCs and reduced LOX-1, MyD88, NF-κB, MCP-1, and TNF-α mRNA and protein expression in vivo and in vitro. These data demonstrate that corilagin exerts antiatherosclerotic effects in vivo and in vitro and that the mechanisms may be closely associated with downregulation of the LOX-1/MyD88/NF-κB pathway.

Promoting effect of pomegranate peel extract on second-degree burn wound-healing through VEGF-A and TGF-ß1 regulation.

Pomegranate peel extract (PPE), a polyphenolic compound derived from pomegranate, has been widely concerned for its anti-oxidant, anti-inflammatory, and bacteriostatic effects. The potential therapeutic effect of PPE on burn injury was investigated, and its possible mechanisms were explored. Minipigs with second-degree burn were treated with PPE, Jing Wan Hong, and silver sulfadiazine. Hematoxylin-eosin (HE) staining was performed to detect burn severity, and then biological tissues were biopsied on days 0, 7, 14, 21, and 28 after administration. Immunohistochemistry, western blot, and real-time polymerase chain reaction (RT-PCR) were used to detect the protein and mRNA expression levels of VEGF-A and TGF-ß1 in skin tissues after treatment with PPE. Furthermore, the skin wound healing at different time points was monitored by macroscopic observation. HE showed that after 28-day PPE treatment, the morphology of the skin tissue showed a significant improvement. Macroscopic data monitoring indicated that the decrustation and fur growing time was shortened. Meanwhile, the rate of wound healing increased after PPE treatment. The combination of immunohistochemistry, western blotting, and RT-PCR showed that after PPE treatment, expression of VEGF-A and TGF-ß1 increased sharply on day 7, maintaining a high level until day 14, showing a downward trend on day 21, and approaching normal levels on day 28. However, in the model group, the protein and mRNA expression levels of VEGF-A and TGF-ß1 increased on day 28 after burn injury, which was a slow process. Results indicated that compared with the model group, the peak expression level of VEGF-A and TGF-ß1 was earlier, which was consistent with decrustation, shortening of fur growing time, and improvement of wound healing rate in minipig second-degree burn model. PPE showed a significant promoting effect on minipig second-degree burn model, which might be associated with the upregulation of the protein and gene expression levels of VEGF-A and TGF-ß1.

Geraniin promotes osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) via activating ß-catenin: a comparative study between BMSCs from normal and osteoporotic rats.

Abnormal osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) has been correlated with the pathogenesis of osteoporosis. Geraniin, a polyphenolic compound isolated from Phyllanthus amarus, is effective in preventing osteoporosis, but the mechanisms of action of geraniin and the impact of osteoporotic condition on drug action are not known. In this study we compared the proliferation and osteoblastic differentiation potential of BMSCs from normal rats with that from osteoporotic rats, and examined the responses of both BMSCs to geraniin in parallel. BMSCs of rats subjected to ovariectomy or sham operation were isolated and treated with geraniin. Cell proliferation was measured by CCK-8 assay. Osteoblastic differentiation was quantified by Alizarin Red S staining and alkaline phosphatase assay. Nuclear translocation of ß-catenin was monitored by immunofluorescent staining. Expression of ß-catenin was determined by Western blot and quantitative real-time polymerase chain reaction. Results showed that the proliferation and osteoblast formation of osteoporotic BMSCs decreased in comparison to that of normal BMSCs. Geraniin enhanced proliferation and osteoblastic differentiation of both BMSCs, but the responses of osteoporotic BMSCs to geraniin were less than those of normal BMSCs. Expression and nuclear accumulation of ß-catenin in osteoporotic BMSCs were found to be diminished. Geraniin increased nuclear translocation and expression of ß-catenin in both BMSCs. This study associated the osteogenic effect of geraniin to activation of Wnt/ß-catenin signaling, and provided rationale for pharmacological investigation of geraniin in osteoporosis prevention and treatment.

Scutellarin protects against vascular endothelial dysfunction and prevents atherosclerosis via antioxidation.

BACKGROUND: Scutellarin is the major constituent responsible for the clinical benefits of Erigeron breviscapus (Vant.) Hand.-Mazz which finds a long history of ethnopharmacological use in Traditional Chinese Medicine. Scutellarin as a pure compound is now under investigation for its protections against various tissue injuries. PURPOSE: This study aims to examine the effects of scutellarin on oxidative stress-induced vascular endothelial dysfunction and endothelial cell damage, and then to evaluate the therapeutic efficacy of scutellarin in preventing atherosclerosis in rats. METHODS: Radical scavenging ability of scutellarin was determined in vitro. Impact of scutellarin on endothelium-dependent relaxation (EDR) of rabbit thoracic aortic rings upon 1, 1-diphenyl-2-picrylhydrazyl (DPPH) challenge was measured. Influences of scutellarin pre-treatment on the levels of reactive oxygen species (ROS), activities of antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase and catalase, and the expression of SOD1 and NADPH oxidase 4 (Nox4) in human umbilical vein endothelial cells (HUVECs) injured by H2O2 were examined. Anti-atherosclerotic effect of scutellarin was evaluated in rats fed with high fat diet (HFD). RESULTS: Scutellarin showed potent antioxidant activity in vitro. Pretreatment of scutellarin retained the EDR of rabbit thoracic aortic rings damaged by DPPH. In H2O2 injured-HUVECs the deleterious alterations in ROS levels and antioxidant enzymes activity were reversed by scutellarin and the mRNA and protein expression of SOD1 and Nox4 were restored also. Oral administration of scutellarin dose-dependently ameliorated hyperlipidemia in HFD-fed rats and alleviated oxidative stress in rat serum, mimicking the effects of reference drug atorvastatin. CONCLUSION: Scutellarin protects against oxidative stress-induced vascular endothelial dysfunction and endothelial cell damage in vitro and prevents atherosclerosis in vivo through antioxidation. The results rationalize further investigation into the clinical use of scutellarin in cardiovascular diseases.

Theoretical Study on Free Fatty Acid Elimination Mechanism for Waste Cooking Oils to Biodiesel over Acid Catalyst.

A theoretical investigation on the esterification mechanism of free fatty acid (FFA) in waste cooking oils (WCOs) has been carried out using DMol(3) module based on the density functional theory (DFT). Three potential pathways of FFA esterification reaction are designed to achieve the formation of fatty acid methyl ester (FAME), and calculated results show that the energy barrier can be efficiently reduced from 88.597kcal/mol to 15.318kcal/mol by acid catalyst. The molar enthalpy changes (ΔrHm°) of designed pathways are negative, indicating that FFA esterification reaction is an exothermic process. The obtained favorable energy pathway is: H(+) firstly activates FFA, then the intermediate combines with methanol to form a tetrahedral structure, and finally, producing FAME after removing a water molecule. The rate-determining step is the combination of the activated FFA with methanol, and the activation energy is about 11.513kcal/mol at 298.15K. Our results should provide basic and reliable theoretical data for further understanding the elimination mechanism of FFA over acid catalyst in the conversion of WCOs to biodiesel products.

Neuroprotective effect of 20(R)-ginsenoside Rg(3) against transient focal cerebral ischemia in rats.

Gensenosides, the active ingredients of Chinese herbal medicine Panax ginseng, have a wide spectrum of medical effects, such as anti-tumorigenic, angiosuppressive, adaptogenic, and anti-fatigue activities. In the present study, we have investigated the neuroprotective effect of 20(R)-ginsenoside Rg(3) (20(R)-Rg(3)) against transient focal cerebral ischemia in male Sprague-Dawley (SD) rats. The middle cerebral artery was occluded for 2h in rats and then reperfused for 24h. The behavioral disturbance was evaluated according to neurological deficit scores, and the infarct volumes were evaluated by 2,3,5-triphenyltetrazolium chloride (TTC) staining; in addition, ischemia-mediated apoptosis was examined using the method of terminal deoxynucleotidyl transferase (TdT)-mediated d-UTP nick end labeling (TUNEL). The expressions of calpain I and caspase-3 mRNA in hippocampal CA1 region were further assayed using in situ hybridization, in order to clarify the neuroprotective mechanism of 20(R)-Rg(3). 20(R)-Rg(3) at the doses of 10 and 20mgkg(-1) i.p., but not 5mgkg(-1), showed significant neuroprotective effect in rats against focal cerebral ischemic injury by markedly reducing cerebral infarct volumes and degrading infarct rate of TTC-stained coronal brain sections, and improving behavior of the animals. Our results also suggested that 20(R)-Rg(3) (10 and 20mgkg(-1)) could significantly suppress the expressions of calpain I and caspase-3 mRNA. These results indicated that 20(R)-Rg(3) attenuates the neuronal apoptosis caused by cerebral ischemia-reperfusion injury and its neuprotective effect may be involved in the downregulation of calpain I and caspase-3.