MCC950 Reduces Neuronal Apoptosis in Spinal Cord Injury in Mice.

BACKGROUND: Traumatic Spinal Cord Injury (SCI) is a severe condition usually accompanied by an inflammatory process that gives rise to uncontrolled local apoptosis and a subsequent unfavorable prognosis. One reason for this unfavorable outcome could be the activation of the NLRP3 inflammasome. OBJECTIVE: MCC950 is a specific inhibitor of NLRP3 that further inhibits the formation of the NLRP3 inflammasome. The purpose of this study was to determine whether the NLRP3 inflammasome was associated with the severity of local apoptosis and whether MCC950 could prevent neuronal apoptosis following SCI. METHODS: In this study, primary cortical neurons were cultured in vitro. With or without pretreatment/ posttreatment with MCC950, neurons were subjected to Oxygen-Glucose Deprivation (OGD) for 2 h and then reperfusion for 20 h. Immunofluorescence was used to determine the expression of NLRP3, ASC, and cleaved caspase-1 in neurons. In vivo, SCI model mice were established with a 5 g weight-drop method. MCC950 was intraperitoneally injected at 0, 2, 4, 6, 8, 10, and 12 days after SCI. Basso Mouse Scale (BMS) scores and footprint assays were used to assess motor function. Paw withdrawal threshold and tail-flick latency were used to assess somatosensory function. H&E, Nissl, and TUNEL staining were used to measure histological changes and apoptosis at 3 days after SCI, and scar formation was observed by Masson staining and GFAP immunohistochemical analysis at 28 days after SCI. RESULTS: Immunofluorescence analysis confirmed that MCC950 inhibited OGD-induced activation of the NLRP3 inflammasome in neurons. Behavioral tests, Masson staining, and GFAP immunohistochemical analysis showed that MCC950-treated mice had improved neuronal functional recovery and reduced scar formation at 28 days after SCI. H&E, Nissl, and TUNEL staining confirmed that there were more living neurons and fewer apoptotic neurons in MCC950-treated mice than control mice at 3 days after SCI. CONCLUSION: These results reveal that MCC950 exerts neuroprotective effects by reducing neuronal apoptosis, preserving the survival of the remaining neurons, attenuating the severity of the damage, and promoting the recovery of motor function after SCI.

Curcumin ameliorates high glucose-induced dysfunction of vasoconstriction via heme oxygenase-1 and GC pathway / 中国病理生理杂志

AIM: To explore the protective effect of curcumin on high glucose-induced decrease in contraction of isolated rat aortic rings, and to elucidate its underlying mechanism. METHODS: The thoracic aortic rings with endothelium of male Sprague-Dawley rats were mounted on a bath system. Isometric contractions of aortic rings were measured. HO activity was also evaluated. RESULTS: (1)Four hours after incubated with 44 mmol/L of glucose (high glucose),the vascular contraction responses to phenylephrine (PE) decreased compared to control group (containing 11 mmol/L of glucose). (2)Coincubation with curcumin (3×10~(-11)-3×10~(-10) mol/L) and high glucose,the high glucose-induced decrease in contraction responses to PE of arteries was partly inhibited. (3)Four hours after incubation with curcumin,the HO activity in thoracic aorta increased. ZnPP,an inhibitor of HO-1,completely abrogated the protection effect of curcumin. (4)Methylene blue,an inhibitor of guanylate cyclase (GC),partly abolished the protective effect of curcumin. CONCLUSION: Curcumin prevents the high glucose-induced decrease in contraction responses to PE in intact aortic rings. The mechanism might be mainly involved in the activation of HO-1 and GC.

Effect of pressure phase plane derived τ and K on evaluation of left ventricular diastolic function in isolated rat heart during ischemia/reperfusion / 中国病理生理杂志

AIM: To analyze and compare the changes of pressure phase plane(PPP) derived τ and K on isolated rat heart during ischemia/reperfusion, and to explore the value of PPP derived τ and K for evaluation of left ventricular diastolic dysfunction. METHODS: LVEDP, -d(p/dt)_(max), τ and K were measured and calculated during ischemia/reperfusion in Sprague-Dawley rat hearts. Meanwhile, the level of lactate dehydrogenase (LDH) in the coronary effluent was measured, and the ultrastructure changes in myocardium were observed under electron microscope. RESULTS: Compared with control group, τ increased and K reduced significantly in each ischemic group in a time dependent manner (P<0.05). With prolonged ischemia, τ was even higher and K was even lower (P<0.05). Compared with control group, except ischemia 15 min, LDH in other groups increased significantly at 10 min and 20 min after reperfusion (P<0.05). Compared with ischemia 30 min, LDH of ischemia 45 min and ischemia 60 min were even higher at 10 min and 20 min after reperfusion (P<0.05). With prolonged ischemia, the abnormal changes of the myocardial ultrastructure were observed. CONCLUSION: PPP derived τ and K may be promising indexes for quantitative assessment of left ventricular diastolic function on isolated) rat heart during ischemia/reperfusion, and indication of the severity of ischemia/reperfusion injury.

Research on a novel method for the evaluation of left ventricular diastolic function / 生物医学工程学杂志

The methods for evaluating left ventricular diastolic function completely and simply are lacking in our country at present. To solve this problem, we presents in this paper a novel method, which is developed according to certain algorithms and mathematic models and is carried out by a MATLAB program. This method mainly obtains dP/dt loops, and calculates four important indices, including left ventricular end-diastolic pressure (LVEDP), Maximal decrease in velocity of left ventricular pressure (--(dP/dt)max), Time constant of ventricular isovolumic relaxation (tau) and Chamber stiffness (Kd), according to the changes of left ventricular pressure. The results obtained from the experiment of isolated rat hearts during ischemia/reperfusion have demonstrated the usefulness and validity of this method. Therefore, with the use of tau and Kd as indicators, this is a sensitive and effective method for evaluating the left ventricular diastolic function, and it can be applied to early detection of left ventricular diastolic dysfunction.

Involvement of COX-2 in antagonism to heme oxygenase-1 on cardioprotection from anoxia/reoxygenation induced injury in rats / 基础医学与临床

Objective To investigate the role of HO-1 in the protection of rat heart from anoxia/reoxygenation induced injury and its underlying mechanism.Methods LVEDP,LVDP and dp/dtmax were analyzed by the Langendorff method in isolated rat heart.Lactate dehydrogenase(LDH), infarct area,COHb and 6-keto-PGF1? were further determined in the experiment.Results After intraperitoneal injection of HO-1 inducer hemin,CO concentration in rat blood enhanced(P

Electrophysiologic study of the biphasic effects of cyclovirobuxine D on arrhythmias / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To explore the possible mechanism of cyclovirobuxine D (CVB-D) in countering and inducing arrhythmia, by way of studying its electro-physiological effect on ventricular papillary muscles of rats in vitro.</p><p><b>METHODS</b>The transmembrane potential of rat's isolated right ventricular papillary muscles were recorded using conventional glass micro-electrode technique.</p><p><b>RESULTS</b>(1) CVB-D in concentration of 13.3-63.3 micromol/L, showed prolonging effect on the action potential repolarization time, mainly the action potential duration 50 (APD50), APD70 and APD90, in dose-dependent manner, in concentration of 33.3-63.3 micromol/L, it could inhibit the resting potential, action potential amplitude (APA) and maximum depolarization velocity (Vmax) in dose-dependent manner. (2) CVB-D also showed time-dependent effect, the effect initiated 10 min after 20 micromol/L was perfused in ventricular muscle, the APD50, APD70 and APD90 were potentiated gradually along with prolongation of action time and reached the peak at 30-40 min, without any potentiation thereafter. (3) CVB-D could markedly prolong the effective refractory period (ERP) of action potential, increase the ratio of ERP/APD. (4) CVB-D in concentration of 33.3 micromol/L could induce frequent, multifocal spontaneous arrhythmia in some cells when the action time was longer than 45 min.</p><p><b>CONCLUSION</b>CVB-D has the action of anti-ventricular arrhythmia, the mechanism is correlated with the prolongation of APD and ERP of ventricular muscle as well as the increase of ERP/APD ratio, while it also has the effect of inducing arrhythmia, the mechanism might be concerned with excessive prolongation of APD and the inhibition on RP, APA and Vmax.</p>

High glucose changes the expression of GRP78 in COX-2 dependent manner in HUVECs / 中国病理生理杂志

AIM:To investigate the effect of high glucose on the expression of an endoplasmic reticulum stress marker glucose-regulated protein 78(GRP78),and explore its underlying mechanism.METHODS:(1) Human umbilical vein endothelial cells(HUVECs) were exposed to normal glucose(5.5 mmol/L) and high glucose(30 mmol/L) for 24 h,36 h or 48 h.Cell viability was determined by MTT method.Cell apoptosis was detected by flow cytometry analysis.The expression of proteins was evaluated by Western blotting analysis.RESULTS:After treated with high glucose for 24-48 h,the expression of GRP78 increased early but decreased at 48 h of incubation,while cyclooxygenase-2(COX-2) expression increased in a time-dependent manner.COX-2 selective inhibitor nimesulide inhibited high glucose induced changes of GRP78 expression and also inhibited high glucose induced cell apoptosis.CONCLUSION:Prolonged high glucose exposure changes the expression of GRP78 in a COX-2 dependent manner in HUVECs.

COX-2 inhibitor protects rat heart against oxidative stress through a pathway independent of cyclooxygenase / 中国病理生理杂志

AIM:To investigate whether nimesulide a selective cyclooxygenase 2 (COX-2) inhibitor and piroxicam (an inhibitor of COX-1) protect the rat hearts against oxidative stress induced by hydrogen peroxide, superoxide anion or hydroxyl free radical. METHODS: Cardiac contractility, lactate dehydrogenase (LDH) and malondialdehyde (MDA) were analyzed by the Langendorff method in isolated rat hearts. Production of 6-Keto-PGF1?, a marker of COX activity, was measured in isolated rat hearts. RESULTS: Rat hearts were exposed to hydrogen peroxide (H2O2), pyrogallol (which produced superoxide anion) or Vit C+Fe2+ (which produced hydroxyl free radical) for 10 min followed by reperfusion for 30 min. H2O2 decreased cardiac contractility and increased LDH release, which was inhibited by nimesulide (3 mg/kg) LVDP 72%?10% vs 61%?11%, LDH (5.5?2.5)U/L vs (8.0?2.1)U/L, P

Inhibitory effect of iron on vasodilatation in the isolated rat aorta / 中国病理生理杂志

AIM: The objectives of the present study were to examine the effect of iron on relaxation of isolated rat aortic rings,and to elucidate the underlying mechanism. METHODS: The thoracic aortic rings of male Sprague-Dawley rats were mounted on bath system. Vasodilatation of aortic rings preconstricted with 10 -6 mol/L of phenylephrine (PE) was measured. RESULTS: (1) Exposure of endothelium-intact aortic rings to ferric ammonium citrate (FAC) for 30 min caused a significant reduction in the relaxation response to acetylcholine (ACh). Pretreatment with L-arginine (L-Arg) before incubation with FAC did not reverse the inhibition of relaxation response to ACh completely. (2) In endothelium-intact aortic rings,L-Arg relaxed the PE preconstricted vessels. Exposure to FAC for 30 min caused the decrease in the relaxation response to L-Arg. There was no difference in the relaxation response to nitric oxide donor,sodium nitroprusside, between endothelium-denuded arteries treated with or without FAC. (3) Dimethyl sulfoxide had no effect on the inhibition of relaxation to ACh by FAC in endothelium-intact rings. Pretreatment of arteries with glutathione and catalase prevented the decrease in relaxation responses to ACh induced by FAC. (4) The nitric oxide synthase activity was (56.49?2.49)?10 3U/g protein in normal aorta with endothelium,while after incubation with FAC for 30 min,it reduced to (25.15?5.75)?10 3U/g protein ( P

Interleukin-2 altered the frequency -dependent relationship of intracellular calcium in rat ventricular myocytes / 中国病理生理杂志

AIM: We examined the effect of interleukin- 2 (IL-2) on calcium handlin g of rat cardiomyocytes. METHODS: The effects of steady state an d transient chan ges in stimulus frequency on the intracellular calcium transient were investigat ed in the isolated ventricular myocytes with spectrofluorometry technique. RESULTS: Under the steady state (0.2 Hz), IL-2 at 2?10 5 U/L decr eased the peak [Ca 2+ ] i and amplitude of the [Ca 2+ ] i transient, increas ed the diastolic calcium level, and prolonged the decay of the calcium transient . At 1.25 mmol/L of extracellular [Ca 2+ ], when increasing the stimulus frequency from 0.2 to 1.0 Hz, diastolic calcium level and peak [Ca 2+ ] i as well as the amplitude of the transient were inc reased. The positive frequency relationship was blunted in the IL-2-treated myoc ytes and this was not normalized by increasing extracellular [Ca 2+ ] t o 2.5 mmol/L . The caffeine induced Ca 2+ release was increased with increase in stimu lus freq uency. IL-2 inhibited the frequency relationship of caffeine induced Ca 2+ releas e. The restitution was not different between control and IL-2 groups at the 1.25 mmol/L of extracellular [Ca 2+ ], which was slowed in IL-2-treated myo cytes when t he extracellular [Ca 2+ ] was increased to 2.5 mmol/L. CONCLUSIO NS: It is concluded that the blunted frequency response of IL-2-treated myocytes was resulted from the decrease in SR Ca 2+ release, which was related to depression of SR funct ion. Despite the evidence of depressed SR Ca 2+ uptake, the restitution o f ca lcium transient at 1.25 mmol/L of extracellular [Ca 2+ ] remains uncha nged, which maybe due to the increase in the Na +/Ca 2+ exchanger activi ty.

Effects of low-glucose on long-term potentiation in the hippocampal slices of immature and adult rats / 中国病理生理杂志

AIM: The effects of low-glucose on long-term potentiation (LTP) in the CA1 region of hippocapal slices of immature (15-16 days old) and adult (56-63 days old) rats were examined. METHODS: The technique of electrophysiology was used, and the slopes of the field excitatory postsynaptic potentials (S-EPSP) were measured. RESULTS: When slices were exposed to glucose medium at concentrations of 3 or 1.5 mmol/L, S-EPSP decreased significantly. In the slices from adult rats, only short-term potentiation was elicited by high frequency stimulation in the medium of 3 or 1.5 mmol/L glucose. However, in the slices from immature rats, LTP was still induced in the medium of 3 mmol/L glucose. CONCLUSION: Low-glucose medium depressed the synaptic transmission. In terms of the synaptic plasticity, the low-glucose endurance in immature rats was stronger than that in adult rats.

Electrophysiological changes in rat ventricular myocardium of experimental diabetes and action of CVB-D / 中国病理生理杂志

AIM: To investigate the electrophysiological changes of diabetic myocardium and effects of cyclovirobuxine D (CVB-D) on its electrophysiology. METHODS: Diabetes was induced in male SD rats, using a single injection of alloxan into tail vein. Untreated age-matched animals were used as controls. Animal electrocardiogram (ECG) was recorded by 2 weeks. Effects of CVB-D on isolated right ventricular papillary muscle from experimental diabetic rats and control group were observed by recording the transmembrane potentials with conventional glass microelectrodes. RESULTS: QT intervals in ECG and action potential duration (APD) at all levels were significantly lengthened in myocardium from week 2 of diabetes. Within the concentration of 13.3-63.3 ?mol?L~(-1), CVB-D prologated APD of diabetes in dose-dependent manner and more than that of control. Within the concentration of 33.3-63.3 ?mol?L~(-1), CVB-D depressed RP, APA, V_(max) and OS of diabetes in dose-dependent way and more than that of control. In addition, CVB-D at concentration of 20 ?mol?L~(-1) prologated APD in a time-dependent manner. The most prologation of APD was attained about 40 min in control, while more than 40 min in diabetes. CONCLUSION: The results show that QT intervals in ECG and APD at all levels are significantly lengthened in myocardium from week 2 of diabetes. CVB-D prolongates APD and inhibits RP, APA, OS and V_(max) more in diabetes than in control.

Effect of interleukin-2 on intracellular calcium levels in rat ventricular myocytes during anoxia and reoxygenation / 中国病理生理杂志

AIM: To investigate the effect of interleukin-2 (IL-2) on the intracellular calcium in electrically stimulated adult rat ventricular myocytes during anoxia and reoxygenation. METHODS: The isolated cardiac ventricular myocytes were exposed to 5 min anoxia followed by 10 min reoxygenation. Chemical anoxia was introduced by Krebs-Henseleit (K-H) solution containing 10 -3 mol/L sodium dithionite. The spectrofluorometric method was used to verify intracellular calcium transient with fura-2/AM as calcium fluorescence probe. RESULTS: It was shown that during anoxia, the amplitude of Ca 2+ transient was decreased, diastolic [Ca 2+ ] i, time to peak and time to relaxation of Ca 2+ transient were increased. All the parameters were got back but did not returned to the pre-anoxia level during reoxygenation. IL-2 at 2?10 5 U/L administrated during anoxia aggravated the effect of rexoxygenation on [Ca 2+ ] i transient. Pretreatment with a specific ? opioid antagonist, nor-BNI (10 -8 mol/L), abolished the effect induced by IL-2 during anoxia on the [Ca 2+ ] i transients, whereas specific ? opioid antagonist, naltrindole (10 -6 mol/L), did not cancel the effect. CONCLUSION: It is concluded that administration of IL-2 during anoxia aggravated the effect of reoxygenation on the [Ca 2+ ] i transients of isolated ventricular myocytes, which was mediated by cardiac ? opioid receptor pathway.

Role of heme oxygenase-1 in cardioprotection against anoxia/reoxygenation induced injury and its mechanisms / 中国病理生理杂志

AIM: To investigate the role of HO-1 in protection of rat hearts against anoxia/reoxygenation-induced injury and its underlying mechanism. METHODS: Cardiac contractility, lactate dehydrogenase (LDH) and infarct area were analyzed by the Langendorff method in isolated rat hearts. RESULTS: After intraperitoneal injection of HO-1 inducer hemin, CO concentration in rat blood enhanced (P

Puerarin protects high glucose-induced injury of vascular relaxation by activation of heme oxygenase-1 / 中国病理生理杂志

AIM:To investigate the effect of puerarin on acute high glucose-induced attenuation of ACh relaxation in isolated rat aortic rings, and to elucidate its underlying mechanism. METHODS: The thoracic aortic rings with endothelium of male Sprague-Dawley rats were mounted on a bath system. Isometric relaxation of aortic rings was measured. RESULTS: ① After incubation with high concentration of glucose (44 mmol/L), the vascular relaxation responses to ACh decreased. ② After coincubation with puerarin (10-10-10-8 mol/L) and high glucose, the high glucose-induced attenuation of ACh relaxation responses of artery was partly inhibited in a dose-dependent manner. ③ After incubation with puerarin for 2 h, the HO-1 activity of thoracic aorta increased. ZnPPIX (an inhibitor of heme oxygenase-1) abrogated the protective effect of puerarin. CONCLUSION: Puerarin prevents the acute high glucose-induced attenuation of endothelium-dependent relaxation in aortic rings. The mechanism might be involved in the activation of heme oxygenase-1.

Vasodilatation induced by Jumi extraction and its mechanisms / 中国病理生理杂志

AIM: The objectives of the present study were to examine the effect of Jumi(JM) extraction on relaxation of isolated rat aortic rings,and to elucidate its mechanisms.METHODS: The thoracic aortic rings with and without endothelium of male Sprague-Dawley rats were mounted on a bath system.Vasodilatation of aortic rings preconstricted with 10-6 mol/L of phenylephrine(PE) was measured.RESULTS: JM extraction(0.5-8 g/L) caused a concentration-dependent relaxation in aortic rings.The extent of relaxation was larger in endothelium-intact aortic rings than that in endothelium-denuded aortic rings.Both L-NAME [a nitric oxide synthase(NOS) inhibitor] and high potassium(20 mmol/L KCl) partly abolished the relaxation action of JM extraction in endothelium-intact aortic rings.Pretreatment with L-NAME also inhibited the relaxation response to JM extraction in endothelium-denuded aortic rings.After incubation with JM extraction,NOS activities enhanced both in endothelium-intact and endothelium-denuded aortic rings.CONCLUSION: JM extraction causes relaxation of aortic rings through endothelium-dependent and independent pathways.The mechanisms might be involved in NOS and endothelium-derived hyperpolarizing factor.

Electrophysiological changes in rat ventricular myocardium at different stages of experimental diabetes / 中国病理生理杂志

AIM: To explore the probable mechanisms of diabetes-induced arrhythmias. METHODS: Diabetes was induced in male SD rats,using a single injection of alloxan into tail vein. Untreated age-matched animals were used as controls. All animals were observed by 2,4,6 and 8 weeks,respectively. Transmembrane potentials were recorded with conventional glass microelectrodes. RESULTS: Action potential duration(APD) at all level (APD10,APD20,APD30,APD50,APD70,APD90) was significantly lengthened in right ventricular papillary muscle from week 2 of diabetes. At week 8,APD was more lengthened at any level of repolarization than that at week 2. No differences were observed in the maximum rate of depolarization(V_ max ),overshoot(OS) and action potential amplitude(APA) as well as the resting membrane potential(RP) from the 2th to 8th week of diabetes. CONCLUSION: The results indicate that prolongation of APD may be prominently responsible for the increased incidence of cardiac re-entry-arrhythmias and sudden death,especially at late stages of diabetes.

Ischemic preconditioning delays ischemia-induced cellular electrical uncoupling in rat heart / 中国病理生理杂志

AIM: To test whether ischemic preconditioning (IPC) del ays ischemia-induced electrical uncoupling by activation of mitochondrial ATP-se nsitive potassium channels (mitoK ATP ). METHODS: Adult rat hearts perfused on a Langendorf f apparatus were subjected to 40 min ischemia followed by 30 min reperfusion. C han ges in coupling were monitored by measuring whole-tissue resistance. RES ULTS: IP C delayed the onset of uncoupling campared to ischemic control; Blocking mitoK ATP channels before the IPC protocol abolished the delay of uncoupling. The specif ic mitoK ATP channel opener diazoxide mimicked the protective effect of IPC . The delay induced by diazoxide was reduced by 5-HD, L-type Ca 2+ channel inhibitor verapamil and a free radical scavenger N-(2-mercaptopropionyl)glycine. CONCLUSIONS: IPC delays the onset of cellular electrical uncoup ling induced by acute ischemia, in which activation of the mitoK ATP channe ls may be involved.

Salvia miltiorrhiza antagonized the alterations of contraction and intracellular calcium of rat ventricular cardiomyocytes induced by anoxia and reoxygenation / 中国病理生理杂志

AIM: To study the effect of salvia miltiorrhiza (SM) on cell contraction and intracellular calcium of enzymatically isolated rat ventricular myocytes during normoxia and anoxia/reoxygenation. METHODS: Contraction and intracellular calcium were determined with video tracking system and spectrofluorometric method, and the chemical anoxic method was employed. RESULTS: The ?d L /d t max , dL of cell contraction and the amplitude of [Ca 2+ ] i in the cardiomyocytes following SM treatment were decreased in a dose-dependent manner. During anoxia, the ?d L /d t max , dL and amplitude of [Ca 2+ ] i were decreased, while the diastolic Ca 2+ level was elevated compared with control group. All the contractile parameters and the diastolic Ca 2+ level were back toward pretreatment values during reoxygenation, but could not return to control level. After the treatment with SM (3 g/L), ?d L /d t max and dL of cell contraction and the amplitude of [Ca 2+ ] i were higher and the diastolic Ca 2+ level was lower than those in anoxia/reoxygenation group. CONCLUSION: SM antagonized effects of anoxia and reoxygenation on cell contraction and intracellular calcium in isolated ventricular myocytes.