[MicroRNA-204 Carried by Exosomes of Human Umbilical Cord-derived Mesenchymal Stem Cells Regulates the Polarization of Macrophages in a Mouse Model of Myocardial Ischemia-reperfusion Injury].

Objective To explore the role and mechanism of microRNA-204(miR-204) carried by the exosomes of human umbilical cord-derived mesenchymal stem cells(hUC-MSC) in regulating the polarization of macrophages in a mouse model of myocardial ischemia-reperfusion(I/R) injury. Methods After the hUC-MSCs were isolated,cultured,and identified,their adipogenic and osteogenic differentiation capabilities were determined.The exosomes of hUC-MSCs were separated by ultracentrifugation,and the expression of CD81,CD63,tumor susceptibility gene 101(Tsg101),and calnexin in the exosomes was determined by Nanoparticle Tracking Analysis software,transmission electron microscopy,and Western blotting.Three groups(hUC-MSC,miR-204 mimic,and negative control) were designed for the determination of the expression of miR-204 in the cells and their exosomes by qRT-PCR.The C57BL/6J mice were randomly assigned into a sham operation group,an I/R group,a hUC-MSC exosomes group,a negative control group,and a miR-204 mimic group.Except the sham operation group,the I/R model was established by ligating the left anterior descending artery.The echocardiography system was employed to detect the heart function of mice.HE staining was employed to observe the pathological changes of mouse myocardium.ELISA was employed to determine the levels of interleukin-1ß(IL-1ß),tumor necrosis factor-α(TNF-α),arginase 1(Arg-1),and IL-10 in the myocardial tissue.After the macrophages of mouse myocardial tissue were isolated,flow cytometry was employed to determine the expression of CD11c and CD206,and ELISA to measure the levels of IL-1ß,TNF-α,Arg-1,and IL-10 in the macrophages. Results hUC-MSCs had adipogenic and osteogenic differentiation capabilities,and the exosomes were successfully identified.Compared with the negative control group,the miR-204 mimic group showed up-regulated expression of miR-204 in hUC-MSCs and their exosomes(P<0.001,P<0.001).Compared with the sham operation group,the modeling of I/R increased the left ventricular end-diastolic diameter(LVEDD)(P<0.001),left ventricular end-systolic diameter(LVESD)(P<0.001),myocardial injury score(P<0.001),and the levels of IL-1ß(P<0.001),TNF-α(P<0.001),and CD11c(P<0.001).Meanwhile,it lowered the left ventricular ejection fraction(LVEF)(P<0.001),left ventricular fractional shortening(LVFS)(P<0.001),Arg-1(P<0.001),IL-10(P<0.001),and CD206(P<0.001).Compared with those in the I/R group,the LVEDD(P<0.001),LVESD(P<0.001),myocardial injury score(P<0.001),and the levels of IL-1ß(P<0.001),TNF-α(P=0.010),and CD11c(P<0.001) reduced,while LVEF(P<0.001),LVFS(P<0.001),and the levels of Arg-1(P<0.001),IL-10(P=0.028),and CD206(P=0.022) increased in the hUC-MSC exosomes group.Compared with those in the negative control group,the LVEDD(P<0.001),LVESD(P<0.001),myocardial injury score(P=0.001),and the levels of IL-1ß(P=0.048),TNF-α(P<0.001),and CD11c(P=0.007) reduced,while the LVEF(P<0.001),LVFS(P<0.001),and the levels of Arg-1(P<0.001),IL-10(P=0.001),and CD206(P=0.001) increased in the miR-204 mimic group. Conclusion The hUC-MSC exosomes overexpressing miR-204 can inhibit the polarization of macrophages in the I/R mouse model to M1-type and promote the polarization to M2-type.

The SNP Rs915014 in MTHFR Regulated by MiRNA Associates with Atherosclerosis.

BACKGROUND/AIMS: The association between the genetic polymorphisms located in either the exon or untranslated region of MTHFR and the risk of human atherosclerosis has been well-documented. This study analyzed MTHFR polymorphisms at the 3'-untranslated region for association with risk and outcome of atherosclerosis in a Chinese Han population. METHODS: The hospital based case-control study was conducted with 500 patients and 600 healthy volunteers as control enrolled. The genotyping was conducted by using Taqman probe. The potential interaction was predicted by multiple bioinformatics analysis. The relative expression of MTHFR was detected by qRT-PCR. Further confirmation was determined by dual-luciferase assay. The plasma homocysteine levels were assayed by ELISA. RESULTS: Cigarette smoking, alcohol consumption, diabetes, hypertension and low levels of serum high-density lipoprotein-C were associated with an increased risk of developing ischemic stroke. MTHFR rs915014 AG and GG genotypes were significantly associated with increased risk of rs915014 compared with the GG genotype. The qRT-PCR confirmed that MTHFR rs915014 AG or GG genotypes could facilitate miR-2861 binding leading to decreased MTHFR levels in cells. In addition, patients carrying the MTHFR rs915014 AG or GG genotypes were associated with accumulation of circulating tHcy volume and a poor atherosclerosis consequence. CONCLUSIONS: This study demonstrates that the MTHFR rs915014 is associated with increased risk of atherosclerosis and might be a shot term outcome biomarker for atherosclerosis patients.

The Effects of Long-Term Tai-Chi Practice on Blood Pressure Under Normal Conditions.

BACKGROUND: Tai-Chi is a popular form of mind-body activity that is suitable for people of all ages. Accumulating evidence have shown that Tai-Chi can help ameliorate cardiovascular diseases. However, the benefits of long-term practice of Tai-Chi on blood pressure control remains unclear. A total of 898 villagers of Chenjiagou were enrolled in this study based on certain inclusion and exclusion criteria. METHODS: All basic information and clinical data were collected by physicians. The effects of Tai-Chi on the systolic blood pressure (SBP), diastolic blood pressure (DBP) and mental status of participants were analyzed. The average practice time of Tai-Chi in the Tai-Chi group was 28.53 years (median 29 years, range 2-69 years). RESULTS: The results showed that SBP and DBP were significantly lower in the Tai-Chi group, compared with the control group and the stop group. Meanwhile, the long-term practice of Tai-Chi significantly improved the body mass index (BMI) (P=0.021). Stepwise regression results demonstrated that Tai-Chi practice, age and BMI could significantly affect blood pressure, with adjusted R2 of 0.218 and 0.159 for SBP and DBP, respectively. In addition, Tai-chi is associated with a lower rate of hypertension after age 40. However, compared with the control group, participants who practiced Tai-Chi for a short time, then stopped, showed no significant improvement in the above-mentioned measurements. CONCLUSIONS: The long-term practice of Tai-Chi was associated with better blood pressure, at least partly through the improvement of BMI and mental state. However, the short-term practice of Tai-Chi may not provide significant benefits on blood pressure in the long term.

Simultaneous determination of nine constituents by validated UFLC-MS/MS in the plasma of cough variant asthma rats and its application to pharmacokinetic study after oral administration of Huanglong cough oral liquid.

Huanglong cough oral liquid (HL), an important traditional Chinese medicine prescription for treating pediatric cough variant asthma (CVA) in Nanjing hospital of traditional Chinese medicine for many years. In this study, a selective, accurate and sensitive ultra fast liquid chromatography extreme resolution coupled with mass spectrometer (UFLC-MS/MS) method was established and validated for the simultaneous determination of nine constituents including morusin, ephedrine, praeruptorin A, praeruptorin B, luteolin, rosmarinic acid, quercetin, amygdalin, caffeic acid in CVA rat plasma sensitized and challenged with ovalbumin and cinnamaldehyde. Plasma samples were prepared by protein precipitation with four-fold amount of methanol. UFLC separation was performed on a Thermo Scientific AcclaimTM RSLC 120 C18 column (2.1 mm × 100 mm, 2.2 µm) with mobile phase containing methanol and 0.1% formic acid-water by gradient elution in 8.1 min at total flow of 0.3 mL/min. The determination of target compounds in plasma was operated by multiple reaction monitoring (MRM) mode with positive and negative electrospray ionization (ESI) source. The correlation coefficients (r) of all compounds were from 0.9930 to 0.9994 in the linear range. Lower limit of quantification (LLOQ, ng/mL) was 0.81, 2.01, 2.11, 1.17, 1.04, 0.89, 0.67, 1.45 and 0.59 for morusin, ephedrine, praeruptorin A, praeruptorin B, luteolin, rosmarinic acid, quercetin, amygdalin and caffeic acid, respectively. Intra- and inter-day accuracy and precision, extraction recovery, matrix effect, carryover effect, dilution integrity, and stability were within the limits specified. The established method was effectively applied to a pharmacokinetic study of the nine compounds in CVA rat plasma following oral administration HL exact (7.5, 15, 30 g/kg).

Feasibility study of a partially hollow configuration for zirconia dental implants.

PURPOSE: To assess the feasibility of a new shape configuration involving a partially hollow and porous lower part for dental implants. MATERIALS AND METHODS: Cylindrical zirconia dental implants coated with bioactive glass were fabricated in the laboratory. Each implant has a solid upper part and a partially hollow lower part. It is open at the bottom with holes through the lower cylindrical walls. This hollow and porous configuration permits bone growth into the lower part of the implant that, over time, forms an interlinked network to lock the implant into the alveolar bone. Biomechanical properties of the new design were evaluated through material testing and experiments with dogs. RESULTS: Mechanical testing of bending strength, hardness, fracture toughness, and fatigue life indicated that zirconia implants with the proposed partially hollow configuration can be fabricated to have structural properties comparable to or exceeding the usual requirements for implants. Animal testing suggests that there is appreciable improvement in lock-in strength and osteointegration due to the hollow and porous configuration. CONCLUSION: The new shape configuration is biomechanically feasible and further research is warranted to improve the design for human use.

Lesions of mediodorsal thalamic nucleus reverse abnormal firing of the medial prefrontal cortex neurons in parkinsonian rats.

The dysfunction of the medial prefrontal cortex is associated with affective disorders and non-motor features in Parkinson's disease. However, the exact role of the mediodorsal thalamic nucleus in the function of the prefrontal cortex remains unclear. To study the possible effects of the mediodorsal thalamic nucleus on the neurological function of the medial prefrontal cortex, a model of Parkinson's disease was established by injecting 8 µg 6-hydroxydopamine into the substantia nigra compacta of rats. After 1 or 3 weeks, 0.3 µg ibotenic acid was injected into the mediodorsal thalamic nucleus of the midbrain. At 3 or 5 weeks after the initial injury, neuronal discharge in medial prefrontal cortex of rat brain was determined electrophysiologically. The numbers of dopamine-positive neurons and tyrosine hydroxylase immunoreactivity in substantia nigra compacta and ventral tegmental area were detected by immunohistochemical staining. Results demonstrated that after injury, the immunoreactivity of dopamine neurons and tyrosine hydroxylase decreased in the substantia nigra compacta and ventral tegmental areas of rats. Compared with normal medial prefrontal cortical neurons, at 3 and 5 weeks after substantia nigra compacta injury, the discharge frequency of pyramidal neurons increased and the discharge pattern of these neurons tended to be a burst-discharge, with an increased discharge interval. The discharge frequency of interneurons decreased and the discharge pattern also tended to be a burst-discharge, but the discharge interval was only higher at 3 weeks. At 3 weeks after the combined lesions, the discharge frequency, discharge pattern and discharge interval were restored to a normal level in pyramidal neurons and interneurons in medial prefrontal cortex. These findings have confirmed that mediodorsal thalamic nucleus is involved in regulating neuronal activities of the medial prefrontal cortex. The changes in the function of the mediodorsal thalamic nucleus may be associated with the abnormal discharge activity of the medial prefrontal cortex neurons after substantia nigra compacta injury. All experimental procedures were approved by the Institutional Animal Care and Use Committee of Xi'an Jiaotong University, China (approval No. XJTULAC2017-067) on August 26, 2017.

Reliability evaluation of auxiliary feedwater system by mapping GO-FLOW models into Bayesian networks.

Bayesian network (BN) is a widely used formalism for representing uncertainty in probabilistic systems and it has become a popular tool in reliability engineering. The GO-FLOW method is a success-oriented system analysis technique and capable of evaluating system reliability and risk. To overcome the limitations of GO-FLOW method and add new method for BN model development, this paper presents a novel approach on constructing a BN from GO-FLOW model. GO-FLOW model involves with several discrete time points and some signals change at different time points. But it is a static system at one time point, which can be described with BN. Therefore, the developed BN with the proposed method in this paper is equivalent to GO-FLOW model at one time point. The equivalent BNs of the fourteen basic operators in the GO-FLOW methodology are developed. Then, the existing GO-FLOW models can be mapped into equivalent BNs on basis of the developed BNs of operators. A case of auxiliary feedwater system of a pressurized water reactor is used to illustrate the method. The results demonstrate that the GO-FLOW chart can be successfully mapped into equivalent BNs.

[Effect of 5-HT7 receptor agonist on pyramidal neurons in the medial frontal cortex in a rat model of Parkinson's disease].

OBJECTIVE: To investigate the activity of pyramidal neurons in the medial prefrontal cortex (mPFC) of normal and 6-OHDA-lesioned rats and the responses of the neurons to 5-hydroxytryptamine-7 (5-HT(7)) receptor stimulation. METHODS: The changes in spontaneous firing of the pyramidal neurons in the mPFC in response to 5-HT(7) receptor stimulation were observed by extracellular recording in normal and 6-OHDA-lesioned rats. RESULTS: Both systemic and local administration of 5-HT(7) receptor agonist AS 19 resulted in 3 response patterns (excitation, inhibition and no change) of the pyramidal neurons in the mPFC of normal and 6-OHDA-lesioned rats. In normal rats, the predominant response of the pyramidal neurons to AS 19 stimulation was excitatory, and the inhibitory effect of systemically administered AS 19 was reversed by GABAA receptor antagonist picrotoxinin. In the lesioned rats, systemic administration of AS 19 also increased the mean firing rate of the pyramidal neurons, but the cumulative dose for producing excitation was higher than that in normal rats. Systemic administration of AS 19 produced an inhibitory effect in the lesioned rats, which was partially reversed by picrotoxinin. Local administration of AS 19 at the same dose did not change the ?ring rate of the neurons in the lesioned rats. CONCLUSION: The activity of mPFC pyramidal neurons is directly or indirectly regulated by 5-HT7 receptor, and degeneration of the nigrostriatal pathway leads to decreased response of these neurons to AS 19.

Changes of synaptic structure after long-lasting LTP induced by high and low frequency tetanus in slices of the rat visual cortex.

Synaptic ultrastructural changes after long-lasting long-term potentiation (L-LTP) induced by 2 and 100 Hz tetanus were investigated by electron microscopic and stereological approach in slices of the developing rat visual cortex (postnatal days 15~21). Both 2 and 100 Hz tetanus-induced L-LTP groups showed significant increases in synaptic interface curvature, synaptic numeric density and postsynaptic density thickness, as well as significant decreases in the cleft width, as compared with the control groups. In addition, the volume density of the active zone (AZ) was increased significantly in the 100 Hz tetanus-induced L-LTP group, but not in the 2 Hz group. The mean lateral area of individual AZ in the 100 Hz group was relatively higher than that in the 2 Hz group. These data suggest that newly formed synapses in the 100 Hz tetanus-induced L-LTP group are larger than those in the 2 Hz group and that 100 Hz tetanus might trigger reorganization or synthesis of postsynaptic cytoskeleton.

Protective effects of quercetin and taraxasterol against H2O2-induced human umbilical vein endothelial cell injury in vitro.

Due to the association between inflammation and endothelial dysfunction in atherosclerosis, the blockage of the inflammatory process that occurs on the endothelial cells may be a useful way of preventing atherosclerosis. In the present study, human umbilical vein endothelial cells (HUVECs) were used to investigate the protective effects of quercetin and taraxasterol against H2O2-induced oxidative damage and inflammation. HUVECs were pretreated with quercetin or taraxasterol at concentrations ranging between 0 and 210 µM for 12 h, prior to being administered different concentrations of H2O2 for 4 h. Cell viability and levels of apoptosis were assessed through cell counting kit-8 (CCK-8) and terminal deoxynucleotidyl transferase dUTP nick end labeling assays, respectively, to determine the injury to the HUVECs. The viability loss in the H2O2-induced HUVECs was markedly restored in a concentration-dependent manner by pretreatment with quercetin or taraxasterol. This effect was accompanied by significantly decreased expression of vascular cell adhesion molecule 1 (VCAM-1) and cluster of differentiation (CD)80 for taraxasterol and that of CD80 for quercetin. In conclusion, the present study showed the protective effects of quercetin and taraxasterol against cell injury and inflammation in HUVECs and indicated that the effects were mediated via the downregulation of VCAM-1 and CD80 expression. This study has therefore served as a preliminary investigation on the anti-atherosclerotic and cardiovascular protective effects of quercetin and taraxasterol as dietary supplements.

Changes in the paired-pulse ratio after long-term potentiation induced by 2- and 100-Hz tetanus in rat visual cortical slices.

The effects of 2- and 100-Hz tetanus on long-term potentiation (LTP) of field potentials recorded from layers II/III and induced in layer IV in rat visual cortical slices were examined. Paired-pulse stimulation was used to probe the different mechanisms of LTP induced by 2- and 100-Hz tetanus. The paired-pulse ratio (PPR) decreased after the LTP induced by 2-Hz tetanus, with the changes in PPR being correlated with LTP amplitude. However, in the LTP induced by 100-Hz tetanus, the changes in PPR were not correlated with LTP expression. These experiments suggest that an enhanced probability of presynaptic transmitter release underlies LTP induced by 2-Hz tetanus, but not LTP induced by 100-Hz tetanus.

Sexual dimorphism in the induction of LTP: critical role of tetanizing stimulation.

Numerous studies have suggested that sexual dimorphism may exist in learning and memory, particularly in types involving the hippocampus. In the present study, we examined the effects of two different tetani on the induction of long-term potentiation in the CA1 region of hippocampal slices from adult female and male rats to determine the sexual differences in their responses to tetanizing stimulation. We found that the induction of LTP is sex-dependent, and that there were clear sexual differences in the responses to different tetanus patterns, but not impulse number or stimulation frequency. Multiple trains of tetani were more effective in the indution of LTP in male rats than in female ones. These findings suggest that male rats can react to a broader range of tetanizing stimulation compared with female rats. Based on our results and the findings of other studies, we propose that the interaction of gonadal hormones with Ca2+/NMDAR and the subsequent regulation of the ERK/MAP kinase pathway are critical mechanisms for sexual dimorphism in the induction of LTP.

Different effects of 2 and 100 Hz tetanus on the expression of long-lasting long-term potentiation in rat visual cortical slices.

Long-term potentiation (LTP) can be induced by various tetanic parameters in the mammalian visual cortex. However, little researches have been done on the relationship between the expression of the long-lasting LTP (late phase LTP or L-LTP) lasting more than 3 h and the tetanic parameters. In the present study, the effects of 2 Hz and 100 Hz tetanic parameters on L-LTP of the field potentials were recorded from the layer II/III of the rat visual cortical slices in response to stimulation of the layer IV. As a result, tetanic parameters that had more than 300 pulses reliably induced L-LTP in the postnatal day 15-21 rats. Obviously different L-LTP expressions were induced by 2 Hz and 100 Hz tetani. There was no difference in L-LTP expression induced by the parameters with the same frequency and different total pulses. These data suggest that L-LTPs induced by different frequency parameters may have different induction and maintenance mechanisms; L-LTPs induced by the parameters with the same frequency may have the same mechanisms.

Morphological alteration of the hippocampal synapses in rats prenatally exposed to magnetic resonance imaging magnetic fields.

The present study investigated the effects of prenatal exposure to the magnetic resonance imaging (MRI) magnetic fields on the synaptic ultrastructure of hippocampal formation of rats at different postnatal development stages. Pregnant rats with gestation of 12-18 days were exposed to the magnetic fields used for MRI clinical applications. When the offspring were 1, 2, or 5-month-old, the synaptic morphologic parameters were measured in female offspring. In the 2-month-old MRI group, the curvature of synaptic interface, the length of active zone and the surface density per unit volume (S(v)) of active zone in the dentate gyrus (DG) decreased significantly, and the width of synaptic cleft increased in the CA1 area. In the 5-month-old MRI group, the width of synaptic cleft increased, the thickness of postsynaptic density and the curvature of synaptic interface decreased significantly in the CA1 region, and the width of synaptic cleft increased in the DG. No significant change was observed in the 1-month-old group. These results suggest that prenatal exposure to the medical magnetic fields causes synaptic ultrastructural changes. The relationship of these changes with behavioral impairments was discussed.

Poly(brilliant cresyl blue)-carbonnanotube modified electrodes for determination of NADH and fabrication of ethanol dehydrogenase-based biosensor.

A single walled-carbon nanotube (SWNT) modified with poly brilliant cresyl blue (PBCB) glassy carbon electrode has been fabricated by a simple, method in order to facilitate electrocatalytic detection of NADH. At this chemically modified electrode, NADH was determined in neutral phosphate buffer solution at 0V (vs. SCE). The amperometric detection provided a wide linear current vs. concentration range (3.0-104.2 microM), a fast response time (within 5s), high sensitivity [9.89nA (muM)(-1)] and a low detection limit (1.0 microM, S/N=3). No interference was observed with a 100-fold excess of dopamine or uric acid. An ethanol biosensor also was developed using the nanocomposite modified electrode, by immobilizing ethanol dehydrogenase with carrageenan. In this case a linear ethanol concentration response was achieved in the range from 0.4 to 2.4mM and the detection limit was estimated to be 0.1mM (S/N=3). The analytical performance achieved with the of the PBCB/SWNT nanocomposite electrode is expected to the development of novel biosensors, biofuel cells, and other bioelectrochemical devices.