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<b>Objective</b> To evaluate the effect of glycogen synthase kinase 3β (GSK3β) on hypoxia/reoxygenation (H/R)-induced injury of senescent renal tubular epithelial cell (RTEC) in aged mice and its regulatory mechanism. <b>Methods</b> RTEC were divided into the Young group (young RTEC with normal growth), Old group (aged RTEC induced by Etoposide), Old+Ad-shNC+H/R group [aged RTEC induced by Etoposide and then transfected with adenovirus negative control (Ad-shNC) for H/R treatment], and Old+Ad-shGSK3β+H/R group (aged RTEC induced by Etoposide and then transfected with short-hairpin RNA-expressing adenovirus with targeted silencing GSK3β for H/R treatment), respectively. Apoptosis level and mitochondrial reactive oxygen species level were detected by flow cytometry. Calcium ion level was determined by immunofluorescence staining. The expression and phosphorylation levels of GSK3β, mitochondria-associated endoplasmic reticulum membrane (MAM)-related proteins of inositol 1,4,5-trisphosphate receptor1 (ITPR1), voltage dependent anion-selective channel 1(VDAC1) and glucose-regulated protein 75 (GRP75) were detected by Western blot. The interaction between GSK3β and MAM-related proteins was analyzed by immunoprecipitation. <b>Results</b> Compared with the Young group, the apoptosis, mitochondrial reactive oxygen species and mitochondrial calcium ion levels were higher in the Old group. Compared with the Old group, the apoptosis, mitochondrial reactive oxygen species and mitochondrial calcium ion levels were higher in the Old+Ad-shNC+H/R group. Compared with the Old+Ad-shNC+H/R group, the apoptosis, mitochondrial reactive oxygen species and mitochondrial calcium ion levels were lower in the Old+Ad-shGSK3β+H/R group, and the differences were statistically significant (all <i>P</i><0.05). Compared with the Young group, the expression levels of ITPR1, GRP75 and GSK3β proteins were up-regulated, the phosphorylation levels of ITPR1 and GRP75 were increased, whereas the total protein and phosphorylation levels of VDAC1 were decreased in the Old group. Compared with the Old group, the expression level of GSK3β protein was unchanged, the total protein and phosphorylation levels of ITPR1 and GRP75 were increased, the expression level of total VDAC1 protein remained unchanged and the phosphorylation level was increased in the Old+Ad-shNC+H/R group. Compared with the Old+Ad-shNC+H/R group, the expression level of GSK3β protein was decreased, the expression levels of total ITPR1, GRP75 and VDAC1 proteins were unchanged, whereas the phosphorylation levels were decreased in the Old+Ad-shGSK3β+H/R group. Immunoprecipitation showed that GSK3β could interact with ITPR1, GRP75 and VDAC1 proteins. <b>Conclusions</b> The expression level of GSK3β is up-regulated in senescent RTEC. Down-regulating GSK3β expression may reduce the phosphorylation level of ITPR1-GRP75-VDAC1 complex, constrain the overload of mitochondrial calcium ion, protect mitochondrial function and mitigate cell damage during reperfusion.
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Objective To evaluate the effect of spliced X-box binding protein 1 (XBP1s) on hypoxia/reoxygenation (H/R) injury of mouse renal tubular epithelial cells and unravel underlying mechanism. Methods Mouse renal tubular epithelial cells were divided into adenovirus negative control group (Ad-shNC group), targeted silencing XBP1s adenovirus group (Ad-shXBP1s group), Ad-shNC+H/R group and Ad-shXBP1s+H/R group. The apoptosis level, mitochondrial reactive oxygen activity, mitochondrial membrane potential and mitochondrial calcium ion level were detected in each group. Chromatin immunocoprecipitation followed by sequencing (ChIP-seq) was employed to analyze the binding sites of XBP1s in regulating the inositol 1,4,5-trisphosphate receptor (ITPR) family. The expression levels of XBP1s and ITPR family messenger RNA (mRNA) and protein were determined in each group. Results Compared with the Ad-shNC group, the apoptosis level was higher, mitochondrial reactive oxygen species level was increased, mitochondrial membrane potential was decreased and mitochondrial calcium ion level was elevated in the Ad-shNC+H/R group. Compared with the Ad-shNC+H/R group, the apoptosis level was lower, mitochondrial reactive oxygen species level was decreased, mitochondrial membrane potential was elevated, and mitochondrial calcium ion level was decreased in the Ad-shXBP1s+H/R group (all P<0.05). Compared with the Ad-shNC group, relative expression levels of XBP1s, ITPR1, ITPR2 and ITPR3 mRNAs and proteins were down-regulated in the Ad-shXBP1s group (all P<0.05). Compared with the Ad-shNC group, relative expression levels of XBP1s, ITPR1, ITPR2 and ITPR3 proteins were up-regulated in the Ad-shNC+H/R group. Compared with the Ad-shNC+H/R group, relative expression levels of XBP1s, ITPR1, ITPR2 and ITPR3 were down-regulated in the Ad-shXBP1s+H/R group (all P<0.05). ChIP-seq results showed that XBP1s could bind to the promoter and exon of ITPR1, the exon of ITPR2, and the exon of ITPR3. Conclusions XBP1s may affect mitochondria-associated endoplasmic reticulum membrane structure and function by directly regulating ITPR transcription and translation. Down-regulating XBP1s may inhibit ITPR expression and mitigate mitochondrial damage.
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Objective:To investigate the cytopathic effect of amino acids 86-175 of rotavirus non-structural protein 4 (NSP4 86-175) on rat cardiomyocytes and the possible mechanism. Methods:Rat H9C2 cardiomyocytes were treated with NSP4 86-175 protein. Changes in the growth and morphology of the cells were observed. The activity of LDH in the cell culture medium was detected. Fluo-3AM was used to label intracellular free calcium ions and the concentrations of calcium ions in rat cardiomyocytes with and without NSP4 86-175 treatment were detected by confocal laser microscopy. The expression of Bax, Bcl-2, caspase-3, 78 kDa glucose-regulated protein (GRP78), C/EBP homologous protein (CHOP) and caspase-12 at mRNA level was detected by real-time PCR. The expression of caspase-3, caspase-8, caspase-9, GRP78, CHOP and caspase-12 at protein level was detected by Western blot. Results:Normal cardiomyocytes showed a typical myoblast-like morphology, presenting as spindle-shaped cells with clear boundaries. Obvious cytopathic effect, vacuolar degeneration, shriveled and rounded cells, and cell fragmentation were observed after the treatment with purified NSP4 86-175 protein. The activity of LDH in cell culture medium was enhanced by NSP4 86-175 protein. NSP4 86-175 protein also enhanced the fluorescence of the calcium ions in rat cardiomyocytes, promoted cell apoptosis, up-regulated the expression of apoptotic factors including caspase-3, caspase-8, caspase-9 and Bax-2, and increased the expression of classical markers of endoplasmic reticulum stress such as GRP78, CHOP and caspase-12. Conclusions:NSP4 86-175 had a cytopathic effect on rat cardiomyocytes, which might be related to the induced intracellular calcium overload, endoplasmic reticulum stress, apoptosis and necrosis. These results might be used as theoretical reference for further study on rotavirus infection and myocardial injury.
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@#Objective To investigate the protective effect and mechanism of the derivative NIM811 on hypoxia/reoxygenation injury of rat hippocampal neuron (HT22) induced by sodium disulfite (Na2S2O4).Methods The hypoxia/reoxygenation cell model was prepared with mouse HT22 cultured cells.The experiment was divided into normal control group,Na2S2O4 group,Na2S2O4+NIM811 group,and NIM811 group.Cell survival rate was detected by CCK-8,flow cytometry was used to detect apoptosis,mitochondrial membrane potential was detected by JC-1 reagent,calcium ion level in mitochondria was observed by Rhod-2 AM,and reactive oxygen species (ROS) was detected by DCFH-DA method.Results Compared with the Na2S2O4 group,after NIM811 treatment:(1)Cell activity increased by 38% (P<0.01);(2)Apoptosis decreased by 27% (P<0.01);(3)Mitochondrial membrane potential increased (P<0.01);(4)The level of calcium ions in the mitochondria decreased (P<0.01);(5)The level of reactive oxygen species (ROS) decreased (P<0.01).Conclusion NIM811 has a protective effect on the hypoxia/reoxygenation injury of mouse hippocampal neurons caused by Na2S2O4.The mechanism may be related to the maintenance of mitochondrial homeostasis and inhibition of cell apoptosis.NIM811 has therapeutic potential for future clinical treatment of ischemic stroke.
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OBJECTIVE：To study the toxicity mechanism of yunacotine-induced arrhythmia in rats. METHODS ：Totally 32 rats were randomly divided by random number table method into normal control group ，yunacotine low-dose and high-dose groups （0.09，0.14 mg/kg），aconitine group （positive control ，0.88 mg/kg），with 8 rats in each group. Administration groups were given the corresponding drugs once a day ，and normal control group was given the constant volume of normal saline ，for consecutive 7 d. After last intragastric administration ，the changes of electrocardiogram （ECG） were observed. The contents of adenosine triphosphate（ATP）in myocardial tissue and Ca 2+ in myocardial cells ，the activities of Na +-K+-ATPase and Ca 2+-Mg2+-ATPase as well as the protein expression of ranolidine receptor 2（RyR2）and Ca 2+-ATPase（SERCA2）in myocardial tissue were determined. RESULTS：Compared with normal control group ，time limit of QRS wave and QTc intervals of rats were prolonged significantly in yunaconitine low-dose group （P＜0.01）. The content of Ca 2 + in myocardial cells ， the ATP contents ， the activities of Ca2+-Mg2+-ATPase and Na +-K+-ATPase as well as the protein expression of SERCA 2 in myocardial tissue were reduced significantly （P＜0.05 or P＜0.01）. The heart rate of rats in yunaconitine high-dose group and aconitine group were increased significantly （P＜ 0.05 or P＜0.01），and time limit of QRS wave and QTc intervals were significantly prolonged （P＜0.01）；the content of Ca 2+ in myocardial cells was increased significantly （P＜0.01）；ATP content ，the activities of Ca 2+-Mg2+-ATPase and Na +-K+-ATPase，and protein expression of RyR 2 and SERCA 2 in myocardial tissue were decreased significantly （P＜0.01）. CONCLUSIONS ： Yunaconitine can induce arrhythmia in rats ，the mechanism of which may be associated with Ca 2+ overload that resulted from reducing the activities of Na +-K+-ATPase and Ca 2+-Mg2+-ATPase and down-regulating the expression of related calcium transporter RyR2 and SERCA 2.
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Background Calcium overload is one of the main reasons that cause photoreceptor apoptosis during theirdegeneration. Our recent data show that flavonoid luteolin protects mouse retinal photoreceptors in diseasedmodel. Aim To explore how luteolin affects the calcium overload in mouse retinal photoreceptors. Methods Fluo4 AM was loaded into retinal slices of wild type mice. Fluorescent images were taken every 5s to monitor thechanges of calcium signal in the soma of photoreceptor. Tissue was perfused with Ringer’s solution as control,then luteolin for 10 min and then Ringer’s as washout. During the perfusion of each solution, high K+ solution wasapplied to elicit calcium overload in photoreceptors. Fluorescent intensity of the photoreceptor soma wasmeasured and compared between control and luteolin solution. Results The high K+ induced-peak fluorescentintensity of Fluo-4 after luteolin treatment was significant higher than that perfused with control solution.Conclusion Luteolin enhances calcium overload in mouse retinal photoreceptors.
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BACKGROUND: The previous research of our group has shown that DAIa2GIP, a new analogue of glucose dependent insulin stimulating polypeptide, has a protective effect on chondrocytes, but its mechanism is not clear. OBJECTIVE: To observe the effect of DAIa2GIP on interleukin-1β (IL-1β) induced apoptosis of chondrocytes, and to explore its molecular biological mechanism. METHODS: The costal chondrocytes of Sprague-Dawley rats were extracted and identified by SABC immunohistochemistry. The third generation cells were divided into six groups: (1) normal control group; (2) IL-1β induction group; (3) DAIa2GIP+IL-1β induction group; (4) DAIa2GIP+IL-1β+pro3GIP (GIPR antagonists) induction group; (5) DAIa2GIP induction group; (6) pro3GIP induction group. After 48 hours of drug treatment, mitochondrial membrane potential was tested, cell apoptosis was detected using Annexin-V FITC Kit (phosphatidylserine eversion analysis), calcium overload of cells was determined under laser confocal microscope, and cytochrome C content were measured by ELISA. The study protocol was approved by the Animal Ethics Committee of Shanxi Medical University. RESULTS AND CONCLUSION: SABC immunohistochemical staining showed that collagen II could be developed as chondrocytes; the maintenance degree of mitochondrial membrane potential was significantly higher in the IL-1β+DAIa2GIP incubation group than the IL-1β induction group, but the potential in both groups was lower than that in the normal control group. The apoptotic rate of chondrocytes in the IL-1β+DAIa2GIP incubation group was significantly lower than that in the IL-1β induction group, but the apoptotic rate in both groups was higher than that in the normal control group. The degree of calcium overload was compared with fluorescence intensity, and the result showed that the IL-1β+DAIa2GIP incubation group had a significantly higher intensity than the IL-1β induction group, and the fluorescence intensity in both groups was higher than that in the normal control group. The release of chondrocyte mitochondrial cytochrome C in the IL-1β+DAIa2GIP incubation group was significantly lower than that in the IL-1β induction group (P < 0.01), and the release amount in both groups was significantly higher than that in the normal control group (P < 0.01). The above four indicators showed no significant difference between the IL-1β induction group and the DAIa2GIP+IL-1β+pro3GIP group, but the values in both groups were lower than those in the control group. There was no significant difference among the normal control group, DAIa2GIP induction group, and pro3GIP induction group. To conclude, DALa2GIP can effectively antagonize IL-1β induced mitochondrial dysfunction of rat chondrocytes, thus antagonizing chondrocyte apoptosis. In this process, DALa2GIP can effectively reduce the degree of calcium overload and the release of cytochrome C.
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To research the synergic effect of Chuanxiong Rhizoma(CR) and borneol(BO) on pro-tecting hippocampus and hypothalamus of the rats from global cerebral ischemia reperfusion (GCIR) injury. Methods GCIR rats were divided into five groups, i. e. sham, model, CR(1.0 g kg"1), B0(0. 16 g kg"1) and CR + BO groups. The contents of Glu, Gly and GABA in brain microdialysis solution were detected by GC-MS. [Ca2+]i of the two regions were measured using a confocal microscope. The apoptotic rate and ultrastructure were obtained by TUNEL stain and transmission electron microscopy, respectively. Results The monotherapy of CR or BO attenuated Ca2 + over-load and improved ultrastructure in both areas. Their synergy showed a better effect. CR alone reduced the apoptotic rate, increased the levels of GABA in both brain areas, while BO only decreased that of Glu. The combination even enhanced the content of Gly in hypothalamus. Conclusions Obvious synergic effects between CR and BO exist in attenuating neuroceliular ex-citotoxicity and calcium overload, while the anti-apop-totic effect might be excluded.
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Objective To investigate the effects of phosphcreatine preconditioning on lung injury induced by renal ischemia-reperfusion (IR) in rats.Methods Forty-five SPF male Sprague-Dawley rats, aged 8-10 weeks, weighing 180-220 g, were randomly divided into 3 groups using a random number table:sham operation group (group S), renal IR group (group IR), and phosphcreatine preconditioning group (group PCr), 15 cases in each group.The rats in group S recieved dissoci ation of renal pedicles and right nephrectomy, on top of which renal IR model was prepared in group IR and group PCr.phosphcreatine 150 mg/kg was injected in group PCr for 30 minutes before ischemia, where as rats in group S and group I/R recieved the normal saline at the same time.The blood samples were obtained from left ventricle at 6 hours after reperfusion, the arterial blood gas analysis was performed in order to determined the oxygen partial pressure (PaO2).Serum levels of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) were also determined.Fluo 3-AM staining and flow cytometry were used to measure the concentration of alveolar macrophage calcium ions.The lung tissue was obtained with HE staining for determination of microscope examination of pathologic changes, and weight/dry (W/D) ratio were also determined.The lung tissue cell apoptotic rate was measured by Annexin V/PI apoptosis detection reagent staining and flow cytometry.Fluo 3-AM staining and flow cytometry were used to measure the concentration of alveolar macrophage calcium ions.Results Compared with group S, the histopathological demages, W/D ratio, lung tissue cell apoptotic rate, the serum levels of MDA and the concentration of alveolar macrophage calcium ions were signifcant increased (P<0.05), whereas the PaO2 and the activity of SOD were signifcantly decreased in group IR and group PCr (P<0.05).Compared with group IR, the histopathological demages, W/D ratio, lung tissue cell apoptotic rate, the serum levels of MDA and the concentration of alveolar macrophage calcium ions were signifcant decreased (P<0.05), whereas the PaO2 and the activity of SOD were signifcantly increased in group PCr (P<0.05).Conclusion Phosphcreatine preconditioning can attenuate lung injury induced by renal I/R, the mechanism is related to inhabit oxidative stress, and reduce cell apopotosis and calcium overload.
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Objective To investigate the effects of ultrasound combined with microbubbles on intracellular Ca2+ homeostasis in carboplatin ( CBP )-treated A549 cell and its possible mechanisms of inhibiting A549 cell line activity . Methods According to whether SonoVue was used or not ,and the different dose of CBP ,the groups A-F were arranged as the ultrasound(US) group(group A) ,the ultrasound combined with microbubbles ( USMB) group( group B) ,the low dose CBP ( 100 μg/ml) + US group( group C) ,the low dose CBP+USMB group( group D) ,the high dose CBP ( 200 μg/ml)+ US group ( group E) and the high dose CBP+USMB group( group F) .A549 cells were bathed and washed by a calcium-free buffer , loaded with Ca2+ indicator fluo-4 AM . Real-time images were acquired using laser confocal microscopy .The fluorescence intensity of intracellular calcium ion concentration ([Ca2+ ]i) in individual living cell was observed and the calcium overload was analyzed . Results After ultrasound irradiation ,the normalized fluorescence intensity of [Ca2+ ]i increased rapidly ,then returned to a new homeostasis (selected cells in groups A ,B ,E ,F) or experienced a second calcium oscillation ( some cells in group C and D) . All the selected cells in group B and some cells in group C and D exhibited superimposed oscillations . The calcium overloading time in group D was longer than those of any other groups . Four cells in group A experienced delayed calcium oscillations . Compared with group A ,the selected cells in other groups exhibited a larger amplitude of calcium oscillation( all P < 0 .05) and the selected cells in group B and D exhibited calcium oscillation for a longer period of time( all P <0 .05) . Conclusions In the calcium-free buffer ,US ,USMB , CBP+ US ,CBP + USMB are direct stimuli of calcium overload in A 549 cells . SonoVue ,CBP ,CBP +SonoVue are all synergistic stimuli of calcium overload in A 549 cells irradiated by ultrasound .US ,USMB and CBP may synergistically induce calcium release from intracellular store sites in A 549 cells . Calcium overload is a possible mechanism of ultrasound combined with microbubbles in assisting CBP chemotherapy .
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Objective • To investigate the role of Rho-associated coiled coil protein kinase 1 (ROCK1) in amyloid β-protein (Aβ) induced damage of rat hippocampal neurons. Methods • The rat primary neurons were treated with Aβ40 oligopeptides to establish a neurotoxicity model. Western blotting was used to detect the protein expression of ROCK1. Its activity was detected by the kit. Confocal laser scanning was used to observe the calcium signal in neurons, and apoptosis of neurons was detected by TUNEL assay. Y-27632, an inhibitor of ROCK1, was added into the culture medium in order to observe its effect on Aβ40. Results • Aβ40 (10 μmol/L) could significantly induce calcium overload, increase ROCK1 expression and activity, and promote apoptosis in primary neurons. Furthermore, ROCK1 inhibitor could decrease all the effect induced by Aβ40. Conclusion • ROCK1 is involved in both Aβ- induced neuronal calcium overload and neurotoxicity, and ROCK1 inhibitor can antagonize the toxic effects of Aβ.
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Objective To study the effect of 20-HETE on apoptosis in cultured neonatal rat cardiomyo-cytes and investigate its mechanism. Methods Neonatal rat cardiomyocytes were cultured in vitro.CCK-8 method was used to detect the cell activity and TUNEL assay was performed to analyze the cell apoptosis. Flou-3/AM la-belled assay was applied to measure the concentration of intracellular calcium([Ca2+]i). Western blot was per-formed to measure the expressions of RyR2,SERCA2a,CaMKII and phospho-CaMKII. Results Treatment with 20-HETE reduced the activity of cardiomyocytes and induced cell apoptosis obviously,while KN-93,an inhibitor of CaMKII,blocked the effects of 20-HETE. Treatment with 20-HETE significantly increased cardiomyocytes [Ca2+]i,up-regulated the expression of RyR2,and down-regulated the expression of SERCA2a,which could be blocked by KN-93. 20-HETE also increased the expressions of CaMKII and phospho-CaMKII in cardiomyocytes, indicating 20-HETE played a role in activating the CaMKII signaling pathway. Conclusions 20-HETE leads to altered functions of cardiac sarcoplasmic reticulum calcium-transport protein RyR2 and SERCA2a via activating the CaMKII signaling pathway,which causes calcium overload and induces apoptosis in neonatal rat cardiomyocytes.
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This study was designed to investigate the role of CD36 in palmitic acid (PA)-induced apoptosis of astrocytes and the potential mechanisms of the action. MTT assay was used to detect cell viability and TUNEL assay to detect cell apoptosis. It was found that PA significantly decreased astrocyte cell viability and increased cell apoptosis. The uptake of BODIPY FL C16 by astrocytes was measured by flow cytometry. The results showed that CD36 played a key role in the process of PA uptake by astrocytes. The changes of intracellular calcium concentration were detected by FLIPR real-time fluorescence recording system. It was found that IP3R mediated PA signal to induce intracellular calcium release and finally caused endoplasmic reticulum calcium depletion. The intracellular ROS level was detected with CM-H2DCFDA fluorescence staining. The ROS level was induced by PA in astrocytes. The effect was blocked by CD36 inhibitor SSO through inhibition of the uptake of PA. PA-induced calcium overload and ROS increase were prevented by IP3R inhibitor APB. SSO, APB and antioxidant NAC all had significant inhibitory effects on PA-induced astrocyte cell viability decrease. In conclusion, CD36 mediates the translocation of PA into astrocytes, which leads to calcium overload, oxidative stress and eventually cell apoptosis.
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Objective To explore the effect of toll-like receptor 4 (TLR4), myeloid differentiation protein-2 (MD2), and stromal interaction molecular 1 (STIM1) for regulating human vascular endothelial calcium overload injury and inflammatory reaction induced by bacterial endotoxin (LPS).Methods Human umbilical vein endothelial cells (HUVECs) were cultured in Dulbecco's modification of Eagle's medium (DMEM). ① The levels of TLR4, MD2 and nuclear factor-κB (NF-κB) were detected by reverse transcriotion-polymerase chain reaction (RT-PCR) before and 0.5, 1, 6, 12, 24 hours after LPS stimulation. ② Intracellular calcium peak level was detected by confocal following probe fluo-3 AM loading in HUVEC cells induced with LPS and transfected by psiSTIM or psiTLR. ③ MD2, STIM1 or NF-κB protein level was detected by immunoprecipitation (IP) and immuno-blotting in HUVEC cells which were transfected by TLR4 inhibited expression (psiTLR) for 12 hours and followed by LPS stimulation for 6 hours. ④ HUVEC cells were randomly divided into 6 groups: control group, LPS group, PDTC 0.1 mg/L group, PDTC 1 mg/L group, psiTLR 1 h group and psiTLR 12 h group. Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were detected by enzyme linked immunosorbent assay (ELISA) in supernatant. The mRNA levels of STIM1 and NF-κB were detected by RT-PCR.Results ① The mRNA levels of TLR4, MD2, and NF-κB gradually increased after LPS induction and peaked at 6 hours (2-ΔΔCt: 23.52±2.88, 17.43±3.43, 18.13±2.99, respectively), which were statistically significant before the stimulation with LPS (2-ΔΔCt: 7.02±2.81, 5.19±3.22, 8.11±1.42, allP < 0.05). ② Extracellular calcium influx in LPS group was increased significantly higher than control group (nmol/L: 108.13±22.33 vs. 41.57±13.19, P < 0.01). Extracellular calcium influx in psiSTIM+LPS group (nmol/L: 62.61±14.12 vs. 108.13±22.33,P < 0.05) and psiTLR+LPS group (nmol/L: 50.78±8.05 vs. 109.43±20.21,P < 0.01) were both suppressed as compared with LPS group. While extracellular calcium peak level in psiTLR+psiSTIM+LPS group further decreased (nmol/L: 39.31±6.42 vs. 109.43±20.21,P < 0.01). ③ MD2 protein but not STIM1 or NF-κB can be detected in anti-TLR4 precipitates in control (ctrl-) by immunoprecipitation. MD2 protein level increased in anti-TLR4 precipitates in LPS group (ctrl+) and was suppressed in TLR4 inhibiting group (psiTLR). ④ The levels of TNF-α in PDTC 1mg/L group were significantly lower than those of LPS group (ng/L: 0.60±0.24 vs. 1.77±0.66,P < 0.01). The levels of IL-6 in PDTC 0.1 mg/L, 1 mg/L group and psiTLR 12 h group decreased significantly lower than that of LPS group (ng/L: 232.10±63.54, 134.32±37.23, 284.23±56.14 vs. 510.22±89.23, allP < 0.05). Compared to LPS group, the mRNA levels of NF-κB and STIM1 were obviously inhibited in PDTC1 mg/L group and psiTLR 12 h group [NF-κB mRNA (2-ΔΔCt): 17.22±2.35, 13.24±3.54 vs. 30.16±2.06; STIM1 mRNA (2-ΔΔCt): 12.57±2.43, 12.21±2.46 vs. 25.12±2.02, allP < 0.05]. Conclusions TLR4, MD2, NF-κB signal and SOC calcium channel STIM1 mediate LPS induced-calcium influx and inflammatory mediators level in HUVEC cells. Extracellular calcium overload and inflammatory response by endotoxin induction can be effectively inhibited by down-regulation of TLR4, NF-κB and/or STIM1.
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Aim To examine the effect of zacopride,a specific inward rectifier potassium channel(IK1)agonist,on L-thyroxine(T4)-induced ventricular remodeling and the underlying mechanism.Methods SD rats were randomly divided as control,L-thyroxine(L-thy,1 mg·kg-1·d-1,ig,10 d)model,L-thy +zacopride(5,15,50 μg·kg-1,respectively,ip),L-thy+zacopride(15 μg·kg-1)+chloroquine(7.5 μg·kg-1,ip)and L-thy+captopril(100 mg·kg-1·d-1,drinking water)groups.Echocardiography and cardiac hypertrophic indexes were measured to confirm the establishment of the ventricular remodeling model.The changes of IK1 and L-calcium current(ICa-L)were detected by whole cell patch clamp technique.The confocal microscopy and fluorescent indicator Fluo-4 were applied to examine the intracellular Ca2+ concentration([Ca2+]i)of isolated adult rat ventricular myocytes.Results L-thyroxine induced left ventricular hypertrophy with increased ratio of heart weight(HW)to body weight(HW·BW-1),ratio of left ventrical weight(LVW)to body weight(LVW·BW-1),left ventricular dimension in diastole(LVIDd),left ventricular dimension in systole(LVIDs),interventricular septum thickness(IVS)and decreased ejection fraction(EF),fractional shortening(FS)(P<0.01).Patch clamp data suggested IK1 was downregulated,while ICa-L was upregulated(P<0.01).In isolated adult cardiomyocytes,L-thyroxine increased the cell area and [Ca2+]i(P<0.01).Zacopride treatment obviously alleviated cardiac remodeling,improved cardiac function,reversed the changes of IK1 and ICa-L,and significantly attenuated intracellular calcium overload(P<0.01).The optimum dose of zacopride in vivo was 15 μg·kg-1 at which the effect was compared favourably with captopril,a classical anti-remodeling agent.Low-dose IK1 atagonist chloroquine could reverse the effect of zacopride(P<0.01).Conclusion Via activating IK1,zacopride could significantly decrease Ca2+ influx and intracellular calcium overload thereby inhibiting L-thyroxine-induced cardiac ventricular remodeling.
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Long non-coding RNA plays an increasingly important role in transcriptional, post-transcriptional and epigenetic levels. In ischemic heart disease, most studies on long non-coding RNA focused on myocardial infarction, hypertrophy and fibrosis, and a few of reports directly focused on the pathological process of myocardial reperfusion injury. Thus, the purpose of this review is to introduce the processes of long non-coding RNA in myocardial reperfusion injury field, aiming to provide a novel research and theraputic method for exploring the mechanism and molecular regulation network involed with reperfusion injury.
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Objective:To investigate the role of melatonin in calcium overload-induced heart injury.Methods:Thirty-two rats were divided into 4 groups:a control group (Control),a melatonin control group (Mel),a calcium overload group (CaP),and a calcium overload plus melatonin group (Mel+CaP).Isolated Sprague Dawley male rat hearts underwent Langendorffperfusion.Left ventricular developed pressure (LVDP) was calculated to evaluate the myocardial performance.Triphenyltetrazolium chloride staining was used to measure the infarct size of myocardium.Lactate dehydrogenase (LDH) activity in the coronary flow was determined.The expressions of caspase-3 and cytochrome c were determined by Western blot.The pathological morphological changes in myocardial fiber were analyzed by HE staining.Results:Compared with the control group,calcium overload significantly induced an enlarged infarct size (P＜0.01),accompanied by the disordered arrangement of myocardial fiber,up-regulation of cytochrome c and caspase-3 (P＜0.01),and the increased activity of LDH (P＜0.01).T hese effects were significantly attenuated by 10 μmol/L melatonin (P＜0.01).Conclusion:Melatonin can alleviate calcium overload-induced heart injury.
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The recent report from National Cardiovascular Center shows that cardiovascular diseases account for more than 40% of disease deaths among residents, so it has become the first cause of death among the residents in our country, and the mortality of coronary heart disease is increasing year by year. Revascularization can quickly open the clogged blood vessels and restore coronary blood supply, so it is an important approach for the treatment of coronary heart disease. However, the revascularization can not terminate the pathological development of coronary heart disease because it is just a local treatment method. In addition, a series of reperfusion injuries after revascularization would seriously restrict its treatment effect for coronary heart disease. Myocardial ischemia reperfusion injury is a complex pathological process, which is closely related to oxygen free radicals, calcium overload and energy metabolism disorder. The calcium overload can be seen during reperfusion in the myocardial cells, and it can cause further damages to the myocardial cells through various mechanisms. Calcium overload is a common pathway of myocardial necrosis and apoptosis, so prevention and treatment of calcium overload is an important method to prevent ischemia reperfusion. The commonly used calcium channel blockers for preventing calcium overload has made great progress, all of which can act on L-type calcium channel of vascular smooth muscle to inhibit calcium overload. However, their clinical application was restrained to a certain extent due to the single target and great side effects. Traditional Chinese medicine (TCM) is a great treasure, and many drugs in TCM have similar effects with calcium antagonists, so the development and application of such drugs would be an important task for contemporary TCM doctors to make up for the deficiency of Western medicine.
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Objective To explore the relationship between the protective effect of hydrogen sulfide (H2 S ) postconditioning against myocardial hypoxia-reoxygenation and the dynamics of actin. Methods Adult rat cardiomyocytes were isolated and the same hatch cells were divided into 4 groups (n =3):normal group (group N),hypoxia-reoxygenation group (group HR),ischemia postconditioning group (group IPTC)and H2 S postconditioning group (group S).The four groups were divided into two sub-groups with or without cytochalasin D (CyD).At the end of reoxygenation,F-actin/G-actin,intracellular calcium ion concentration (Ca2+ )and pH value were detected with laser scanning confocal microscopy, meanwhile the level of p-p38MAPK was detected with Western blot.Results The fluorescence intensity of F-actin/G-actin of group HR,group IPTC and group S were significantly higher than that of group N (P <0.05).The fluorescence intensity of Ca2+ of group HR was higher than that of group N,group IPTC and group S (P <0.05);The intensity of Ca2+ of all group with CyD treatment was higher than those without (P <0.05);The fluorescence intensity of pHi of group N and group HR with CyD treatment was higher than those without;The fluorescence intensity of pHi of group IPTC and group S was lower than those without;The flu-orescence intensity of pHi of group HR was lower than that of group N,group IPTC and group S (P <0.05), respectively;the pHi of group N and group HR sub-group with CyD treatment was higher than those without correspondingly (P <0.05),however,the pHi of IPTC and S sub-groups were lower than their corresponding groups (P <0.05).The level of p-p38MAPK in group HR was significantly higher than those of other groups (P <0.05);there was no difference among groups N,IPTC and S.Conclusion Hydrogen sulfide postcondi-tioning could promote F-actin to remodel and stabilize the cellular environment.Hypoxia-reoxygenation pro-motes the phosphorylation level of p38MAPK,which could be surpressed by H2 S postconditioning.
الملخص
OBJECTIVE To observe the effect of natrin from Naja naja atra(Chinese cobra)on intracellular free calcium overload,and to discuss the protective effect and the possible mechanism of natrin on myocardium calcium(Ca2+)and potassium(K+)ion channels in the primary cardiomyocytes of SD neonatal rats. METHODS The primary cardiomyocytes of SD neonatal rats were used,which were respectively pretreated with natrin 5,25 and 125 mg · L-1 for 24 h before injury was induced by H2O2 0.3 mmol · L- 1. The dynamic variation of intracellular calcium was monitored by laser confocal microscopy using Fluo-3 as Ca2+fluorescence probe. Additionally,the cardio myocytes of neonatal rats were pretreated for 24 h using different concentrations of natrin 5,25,125 mg · L-1 and verapamil 5 nmol · L-1,followed by exposure to H2O2 0.3 mmol · L-1 for 15 min. Then,the mRNA expressions of calcium channels subunits Cav1.2,Calm,RyR2 and potassium channel Kir6.2 were analyzed by FQ-PCR method. RESULTS Laser confocal microscopy revealed that H2O2 obviously caused calcium overload in cardiomyocytes, giving rise to 49.37% fluorescence increase in intracellular calcium compared with the control group(P<0.01). However,natrin 5,25 and 125 mg·L-1 resulted in 27.52%, 12.71% and 5.15% fluorescence increase in intracellular calcium,respectively,compared with the control group(P<0.01). Moreover, the PCR results showed that the mRNA expressions of Cav1.2, Calm and RyR2 in the myocardial cells treated with H2O2 were increased 2.78,2.26,and 5.34 times as compared with the control group,while Kir6.2 displayed a 1.79-fold expression level(P<0.01). By contrast, the combination of natrin and verapamil significantly decreased the mRNA expression of Cav1.2,Calm and RyR2,compared to the H2O2-treated group(P<0.01). Meanwhile,the expression of Kir6.2 was considerably higher than that of the H2O2-treated group(P<0.05). CONCLUSION Natrin can reduce the intracellular calcium overload of cardiomyocytes induced by H2O2 and shows a protective effect against oxidative damage for cardiomyocytes. The possible mechanism is that natrin can decrease the mRNA expression of Cav1.2,Calm,RyR2 and increase the expression of Kir6.2 of the H2O2-induced cardiomyocytes.