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Ischemia-reperfusion injury (IRI) refers to the reperfusion injury caused by the recovery of blood supply of ischemic tissues or organs, which commonly occurs in organ transplantation and other surgical procedures. IRI may cause a series of severe clinical issues, such as delayed graft function, acute kidney injury, myocardial infarction, ischemic stroke and circulatory arrest, etc. These events yield high incidence and fatality. At present, no effective solution has been available. Transient receptor potential canonical 6 (TRPC6), a member of Ca2+ channel family, is highly expressed in multiple types of cells. It may adjust many physiological functions by regulating intracellular Ca2+ concentration, which has become an important target for developing therapeutic drugs for multiple diseases. In this article, research progresses on the introduction and function of TRPC6, the association between TRPC6 and IRI and the therapeutic prospect of TRPC6 targeted drugs in IRI were reviewed, aiming to provide novel insights into the prevention and treatment of IRI during organ transplantation
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Objective@#To investigate the effect and related mechanism of homocysteine (Hcy) on calcium overload in neonatal rat atrial cells (NRICs).@*Methods@#NRICs were assigned to 9 groups after culture for 3 days: (1) control group; (2) Hcy group (0, 50, 100, 200, 500 μmol/L for 48 hours); (3) antioxidant group (NAC, 10 μmol/L for 24 hours); (4) Hcy+NAC group (500 μmol/L Hcy for 48 hours, then treated with 10 μmol/L NAC for 24 hours); (5) calcium/calmodulin dependent protein kinase Ⅱδ (CaMKⅡδ) inhibitor group (KN-93, 3 μmol/L KN-93 for 5 hours); (6) specific sodium current inhibitor group (ELE, 1 μmol/L ELE for 5 hours); (7) Hcy+KN-93 group (500 μmol/L Hcy for 48 hours, then treated with 3 μmol/L KN-93 for 5 hours); (8) Hcy+ELE group (500 μmol/L Hcy for 48 hours, then treated with 1 μmol/L ELE for 5 hours; (9) Hcy+KN-93+ELE group (500 μmol/L Hcy for 48 hours, then treated with 3 μmol/L KN-93 and 1 μmol/L ELE for 5 hours). Moreover, NRICs were also treated with CaMKⅡδ-siRNA lentivirus, and Nav1.5-siRNA lentivirus, negative lentivirus carrier containing green fluorescent protein (GFP) for 24 hours. The MOI values of the three groups were 10. Infection efficiency of lentivirus was determined by observing the percentage of GFP fluorescence under inverted fluorescence microscope after transfection for 24 hours, and cultured regularly with simultaneous Puro screening, then cells were grouped as Hcy+CaMKⅡδ-siRNA group, Hcy+Nav1.5-siRNA group and Hcy+negative group. The concentration of Ca2+ in NRICs ([Ca2+]i) of various groups was detected through Fluo-4/AM fluorescence probe, then 2', 7'- two chlorofluorescein diacetate (DCFH-DA) was used as a probe to detect reactive oxygen species (ROS) in NRICs by flow cytometry. The malondialdehyde (MDA) was detected by the activity of superoxide dismutase (SOD) and xanthine oxidase was detected by thiobarbituric acid colorimetry. The protein and mRNA expression level of CaMKⅡδ and Nav1.5 in NRICs were detected by Western blot and quantitative real-time PCR.@*Results@#(1) ROS, MDA and SOD were similar between NAC group and control group, ROS and MDA were significantly increased, while SOD was significantly reduced in Hcy group in a concentration-dependent manner. (2) [Ca2+]i: The level of [Ca2+]i was (155.57+7.25), (187.43+13.07), (248.98+27.22) and (307.36+15.09) nmol/L in 50, 100, 200 and 500 μmol/L Hcy groups, which was significantly higher than that in the control group ((123.18+7.24) nmol/L, P<0.01). In addition, the level of [Ca2+]i in Hcy+NAC group ((222.87+23.71)nmol/L) was significantly lower than that in Hcy 500 μmol/L group ((305.15+39.45) nmol/L, P<0.05), while [Ca2+]i level was similar between NAC group and the control group. (3) The protein expression of CaMKⅡδ and Nav1.5 was significantly upregulated in Hcy groups than in the control group. The protein expression level of CaMKⅡδ-Thr287 was significantly lower in NAC group than in Hcy 500 μmol/L group (P<0.01), however, there was no significant difference on the protein expression levels of CaMKⅡδ-Thr287 and Nav1.5 between NAC group and control group (all P>0.05). (4) The protein expression levels of CaMKⅡδ-Thr287 and the concentration of [Ca2+]i were significantly lower in Hcy+KN-93 group and Hcy+KN-93+ELE group than in Hcy 500 μmol/L group (P<0.05). [Ca2+]i concentration was significantly lower in Hcy+KN-93 group, Hcy+ELE group and KN-93+ELE+Hcy group than in Hcy 500 μmol/L group (P<0.05). (5) The mRNA and protein expression levels of CaMKⅡδ and Nav1.5 in each group infected with lentivirus: the GFP expression was ideal post lentivirus transfection for 24 hours (up to 90%), which was significantly lower in the CaMKⅡδ-siRNA group and Nav1.5-siRNA group than in the negative infection group (all P<0.05), which was similar between negative infection group and control group (P>0.05). Moreover, the mRNA and protein expression levels of CaMKⅡδ and CaMKⅡδ-Thr287 was significantly lower in Hcy+Nav1.5-siRNA group than in Hcy+negative infection group (P<0.05). The protein and mRNA levels of Nav1.5 were similar between Hcy+CaMKⅡδ-siRNA group and Hcy+negative infection group (P>0.05).@*Conclusions@#Hcy can induce calcium overload in NRICs by increasing oxidative stress, upregulating the sodium channel protein, and activating the late sodium current and phosphorylating CaMKⅡδ.
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Aim To explore the therapeutic effects of main active compounds of panaxadiol ( PD ) in on Alzheimer’s disease ( AD) via network pharmacologi-cal analysis and Mmolecular docking. Methods A to-tal of 107 prescriptions for AD treatment were screened by using network pharmacology, screening for the high-est frequency of ginseng and its target for AD. Use mo-lecular docking technology was used to find components with the highest score for non-receptor tyrosine kinase ( FYN) docking. Then we successfully estimatedestab-lished AD cell model with overexpressinged APP pro-teins in vitro. Next,the cell viability was detected by MTT assay,the cell damage was detected by LDH as-say,the apoptosis and intracellular Ca2+concentration were detected by flow cytometry, and phosphorylated FYN protein expression was detected by Western blot detection of . phosphorylated FYN protein expression. Results Eighteen active components of Gginseng and 29 AD-related targets were screened by the method of network pharmacology. The results of molecular doc-king showed that PD had strong binding effects with FYN. The results showed that PD could increase the survival rate of cells,reduce the release of LDH,reduce apoptosis,and improve AD cells’ intracellular Ca2+o-verload and reduce the expression of FYN-Y416 pro-tein. Conclusion The experimental results of network pharmacology were are verified and the protective effect of PD on AD may be related to inhibition of FYN signa-ling pathway.
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Objective To investigate the role of mitochondrial calcium uptake 1 (MICUI) in myocardial hypertrophy of mice and underlying mechanism.Methods The model of myocardial hypertrophy was established via incubation of mouse cardiac myocytes (MCM) with 300nmol/L angiotensin Ⅱ (Ang Ⅱ) for 48 hours in vitro.After that,MICU1 specific small interfering RNA (siRNA) was delivered to knockdown MICU1 levels in MCM.On the other hand,adenovirus-mediated over-expression of MICU 1 was transfected into MCM.Accordingly,the expressions of ANP and BNP in myocardial cells were measured by qRT-PCR.Mitochondrial membrane potential and ATP contents were detected byJC-1 assay kit and ATP assay kit,respectively.Then,Western blotting and qRT-PCR were used to detect the levels of MICU1 in myocardial cells.The mitochondrial Ca2+ contents were measured via atomic absorption flame spectroscopy.The size of myocardial cells was determined by α-actinin staining.Results Mitochondrial membrane potential and ATP contents in hypertrophic cardiomyocytes induced by Ang Ⅱ were both decreased.Meanwhile,myocardial hypertrophy significantly increased mitochondrial Ca2+ contents but decreased MICU1 levels.With the method of genetic intervention,we found that MICUI deficiency exacerbated mitochondrial Ca2+ overload,increased cell surface and elevated the expression of BNP.Conversely,the overexpression of MICU1 obviously decreased mitochondrial Ca2+ overload,cell surface of MCM and expressions of ANP and BNP.Conclusion MICU1 alleviates Ang Ⅱ-induced myocardial hypertrophy via inhibiting mitochondrial Ca2+ overload.
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To study the antagonistic effect of ginkgolide homologues on platelet-activating factor (PAF)-induced platelet aggregation and investigate its neuroprotective effect. PAF was used as a coagulant, and ginkgolides were added to the rabbit blood samples respectively. The inhibitory effect of each compound on platelet aggregation was detected by turbidimetry. In L-glutamate induced primary cortical neuron cell injury model, MTT assay was used to detect cell viability. Intracellular free Ca2+ concentration in neurons was measured by using the fluorescent Ca2+ indicator Fura-2 AM. Morphological observation and Hoechst 33258 staining were used to detect the inhibitory effect of ginkgolide on neuronal apoptosis. The results showed that the inhibitory effect on PAF-induced platelet aggregation activity in ginkgolide homologues was ginkgolide K (GK), ginkgolide B (GB), ginkgolide A (GA), ginkgolide C (GC), ginkgolide M (GM), ginkgolide J (GJ) and ginkgolide (GL) from high to low. GB and GK (1-100 μmol•L ⁻¹) could significantly reduce the cell damage caused by L-glutamate, with survival rate increasing, intracellular calcium concentration reducing and cell morphology restoring. This paper has identified the activities and characteristics of various compounds of ginkgolide homologues on PAF-induced platelet aggregation as well as its neuroprotective effect.
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Objective To explore the effect of TNF-α in intracellular Ca~(2+)-overload associated myocardial injury. Methods Thirty Wistar rats were randomly divided into three groups:control group,Ca~(2+)+-paradox group,and pentoxifylline treatment group. The intracellular Ca~(2+)-overload rat model was established by pre-filling the rats with Langendorff for 20 minutes,isolated rat hearts subjected to Ca~(2+)-depletion for 5 minutes and Ca~(2+)-repletion for 30 minites(Ca~(2+)-paradox). Changes in hemodynamics indexes were monitored continuously. TNF-α in cardiac tissues was tested by ELISA method,and nuclear factor-κB(NF-κB)in cardiac tissues was detected with Western blot. Results Dramatic depression in left ventricle contraction function was found in the Ca~(2+)-paradox hearts:significant decrease in left ventricular diastolic pressure(LVDP),markedly elevated left ventricular end diastolic pressure(LVEDP),decreased dP/dt ratio,increased TNF-α content,decreased cytosolic/homogenate NF-κB ratio. All these changes in Ca~(2+)-paradox group were significantly attenuated upon the treatment with 100 μmol/L pentoxifylline. Conclusions Activation of NF-κB and increased production of TNF-α may play important roles in cardiac injury associated with intracellular Ca~(2+)-overload.
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Objective To evaluate the effect of improving microcirculation and preventing cell Ca 2+ overload in preventing the development of acute pancreatitis (AP).Methods 278 AP patients admitted from 1990 to 1994 and from 1995 to 1999 were retrospectively analyzed. Routine conservative managements were performed in the first stage,improving microcirculation and preventing cell Ca 2+ overload were performed in the second stage.Results During the first period,there were 124 patients with AP.The conversion of mild AP to severe AP developed in 28 of 120 patients with mild AP.18 of 32 patients with severe AP developed systemic complications,24 patients developed local complications,there were 9 deaths.During the second period,154 cases were treated ,the conversion of mild AP to severe AP presented in 16 of 149 patients with mild AP. 4 of 21 patients with severe AP presented systemic complications,19 patients presented local complications, 3 patients died.Conclusion Improving pancreatic microcirculation and preventing pancreatic cell Ca 2+ overload are helpful not only to prevent the conversion of mild pancreatitis to severe pancreatitis,but also to prevent progressive pancreatic necrosis, and improve the prognosis of acute pancreatitis.
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AIM: To observe the changes of Ca-L current (ICa-L) and to investigate the mechanism of salvia miltiorrhizae (SM) for eliminating Ca~2+ overloaded in cells during acute hypoxia/reoxygenation. METHODS: The whole cell patch clamp technique was applied to study the changes of ICa-L. Different concentrations (32, 320, ~3 200 mg/L) of SM were added to the ventricular myocytes isolated from guinea pigs by enzyme digestion. RESULTS: SM (32, 320, ~3 200 mg/L) decreased the amplitude of ICa-L in a concentration-dependent manner regardless of these cells were under normoxia, hypoxia or reoxygenation. Furthermore, SM at low concentration (32 mg/L) was more effective to hypoxia or reoxygenation-treated cells than that to the cells under normoxia condition. CONCLUSION: These results indicate that SM effectively decreases the abnormal raised amplitude of ICa-L in ventricular myocytes under hypoxia or reoxygenation conditions, preventing Ca~2+ overloaded in the cells. [