DESENSITIZATION OF ACETYLCHOLINE ON THE INHIBITION EFFECTS OF BLOOD PRE SSURE IN ANESTHETIZED CANINE

Objective To investigate the desensitization of acetylcholine (ACh) on the inhibition effects of blood pressure (BP) in anesthe tized canine and build a model for studying desensitization in vivo. Methods Through changing the intervals (120, 100, 80, 60, 40, 20 seconds) of twice ACh administration (each was 15μg·kg -1,i.v.), the desensitization on the effect of systemic blood pressure of the first ACh in jection towards the subsequent ACh administration was observed. Results When ACh administration intervals were 40, 60, 80 , 100 seconds, the percentages of desensitization of ACh on systemic blood press ure were significantly increased (P<0.05). However, as the intervals were 20 and 120 seconds, the effects of twice ACh administration had no significant dif ference (P>0.05). Conclusion The results indicated that ACh contents in blo od might influence the action of next ACh administration. To some extent, the hi gher the concentration of ACh in blood, the bigger the ratio of desensitization of exogenous ACh is. In addition, this method of twice drug administration could be used as a model of studying desensitization in vivo.

Carvedilol protected diabetic rat hearts via reducing oxidative stress

Oxidative stress plays a dominant role in the pathogenesis of diabetes mellitus. Bcl-2 gene has close connection with antioxidant stress destruction in many diseases including diabetes. Carvedilol, an adrenoceptor blocker, also has antioxidant properties. To study the effect of carvedilol on the antioxidant status in diabetic hearts, we investigated carvedilol-administrated healthy and streptozotocin-induced diabetic rats. After small and large dosage carvedilol-administered for 5 weeks, hemodynamic parameters, the levels of malondialdehyde, activities of antioxidant enzymes and expression of Bcl-2 mRNA in the cardiac tissues were measured. The diabetic rats not only had cardiac disfunction, weaker activities of antioxidant enzymes, but also showed lower expression of Bcl-2. Carvedilol treatment increased activities of antioxidant enzymes and expression of Bcl-2 in healthy rats as well as diabetic rats. These results indicated that carvedilol partly improves cardiac function via its antioxidant properties in diabetic rats.

Impaired coronary microvascular endothelial function in men with metabolic syndrome

AIM: To assess coronary endothelial function of conduit and resistance vessels in patients with metabolic syndrome (MS). METHODS: Seventy-eight men (mean age, 57 years) with chest pain and angiographically normal coronary arteries were included in the study. Patients with coronary spastic angina were excluded. Changes in coronary artery diameter and coronary blood flow (CBF) in response to acetylcholine (ACh) were determined using quantitative coronary angiography and Doppler velocity measurements. Coronary flow reserve was calculated as the ratio of coronary blood velocity after adenosine triphosphate infusion relative to baseline values. Patients were divided into two groups based on the presence or absence of MS. RESULTS: There were 24 patients in the MS group (31%). The increase in CBF in response to ACh infusion was impaired in the MS group (P < 0.0001) compared to the non-MS group, whereas changes in coronary artery diameter in response to ACh infusion did not differ between the two groups. Multivariate regression analysis revealed that MS was a significant factor associated with the lesser change in CBF induced by ACh infusion at 30 μg/min (P < 0.0001, r 2 = 0.46). CONCLUSION: Coronary endothelial dysfunction was present at the level of resistance vessels but not conduit vessels in the MS patients included in our study.

Huangqi Decoction,a compound Chinese herbal medicine,inhibits the proliferation and activation of hepatic stellate cells by regulating the long noncoding RNA-C18orf26-1/microRNA-663a/transforming growth factor-βaxis

Objective Huangqi Decoction(HQD),a classical traditional Chinese medicine formula,has been used as a valid treatment for alleviating liver fibrosis;however,the underlying molecular mechanism is still unknown.Although our previous studies showed that microRNA-663a(miR-663a)suppresses the proliferation and activation of hepatic stellate cells(HSCs)and the transforming growth factor-β/small mothers against decapentaplegic(TGF-β/Smad)pathway,whether long noncoding RNAs(lncRNAs)are involved in HSC activation via the miR-663a/TGF-β/Smad signaling pathway has not yet reported.The present study aimed to investigate the roles of lncRNA lnc-C18orf26-1 in the activation of HSCs and the mechanism by which HQD inhibits hepatic fibrosis.Methods The expression levels of lnc-C18orf26-1,miR-663a and related genes were measured by quantitative reverse transcription-polymerase chain reaction.HSCs were transfected with the miR-663a mimic or inhibitor and lnc-C18orf26-1 small interfering RNAs.The water-soluble tetrazolium salt-1 assay was used to assess the proliferation rate of HSCs.Changes in lncRNA expression were evaluated in miR-663a-overexpressing HSCs by using microarray to identify miR-663a-regulated lncRNAs.RNA hybrid was used to predict the potential miR-663a binding sites on lncRNAs.Luciferase reporter assays further confirmed the interaction between miR-663a and the lncRNA.The expression levels of collagen α-2(I)chain(COL1A2),α-smooth muscle actin(α-SMA)and TGF-β/Smad signaling pathway-related proteins were determined using Western blotting.Results Lnc-C18orf26-1 was upregulated in TGF-β1-activated HSCs and competitively bound to miR-663a.Knockdown of lnc-C18orf26-1 inhibited HSC proliferation and activation,downregulated TGF-β1-stimulatedα-SMA and COL1A2 expression,and inhibited the TGF-β1/Smad signaling pathway.HQD suppressed the proliferation and activation of HSCs.HQD increased miR-663a expression and decreased lnc-C18orf26-1 expression in HSCs.Further studies showed that HQD inhibited the expression of COL1A2,α-SMA,TGF-β1,TGF-βtype I receptor(TGF-βRI)and phosphorylated Smad2(p-Smad2)in HSCs,and these effects were reversed by miR-663a inhibitor treatment.Conclusion Our study identified lnc-C18orf26-1 and miR-663a as promising therapeutic targets for hepatic fibrosis.HQD inhibits HSC proliferation and activation at least partially by regulating the lnc-C18orf26-1/miR-663a/TGF-β1/TGF-βRI/p-Smad2 axis.

Cell sheet formation enhances the therapeutic effects of human umbilical cord mesenchymal stem cells on myocardial infarction as a bioactive material

Stem cell-based therapy has been used to treat ischaemic heart diseases for two decades.However,optimal cell types and transplantation methods remain unclear.This study evaluated the therapeutic effects of human umbilical cord mesenchymal stem cell(hUCMSC)sheet on myocardial infarction(MI).Methods:hUCMSCs expressing luciferase were generated by lentiviral transduction for in vivo bio-luminescent imaging tracking of cells.We applied a temperature-responsive cell culture surface-based method to form the hUCMSC sheet.Cell retention was evaluated using an in vivo bio-luminescent imaging tracking system.Unbiased transcriptional profiling of infarcted hearts and further immunohistochemical assessment of monocyte and macrophage subtypes were used to determine the mechanisms underlying the therapeutic effects of the hUCMSC sheet.Echocardiography and pathological analyses of heart sections were performed to evaluate cardiac function,angiogenesis and left ventricular remodelling.Results:When transplanted to the infarcted mouse hearts,hUCMSC sheet significantly improved the retention and survival compared with cell suspension.At the early stage of MI,hUCMSC sheet modulated inflammation by decreasing Mcp1-positive monocytes and CD68-positive macrophages and increasing Cx3cr1-positive non-classical macrophages,preserving the cardiomyocytes from acute injury.Moreover,the extracellular matrix produced by hUCMSC sheet then served as bioactive scaffold for the host cells to graft and generate new epicardial tissue,providing mechanical support and routes for revascularsation.These effects of hUCMSC sheet treatment significantly improved the cardiac function at days 7 and 28 post-MI.Conclusions:hUCMSC sheet formation dramatically improved the biological functions of hUCMSCs,mitigating adverse post-MI remodelling by modulating the inflammatory response and providing bioactive scaffold upon transplantation into the heart.Translational perspective:Due to its excellent availability as well as superior local cellular retention and survival,allogenic transplantation of hUCMSC sheets can more effectively acquire the biological functions of hUCMSCs,such as modulating inflammation and enhancing angiogenesis.Moreover,the hUCMSC sheet method allows the transfer of an intact extracellular matrix without introducing exogenous or synthetic biomaterial,further improving its clinical applicability.