Effects of nicotine on activation of PMNs and the ICAM-1 mRNA expression of HUVEC

AIM: To investigate the effects of nicotine on activation of PMNs, adhesion of PMNs-HUVEC and expression of ICAM-1 mRNA in HUVEC. METHODS: Activation of PMNs was measured by detecting the activity of β-glucuronidase and lysozym of PMNs. Adhesion of PMNs and HUVEC was observed. Northern blot was conducted for quantitating ICAM-1 mRNA. RESULTS: Nicotine could increase the activity of β-g [(8.76± 1.01)μg/10⁷·h vs(14.87±2.00)μg/10⁷·h,P<0.05]and Lysozym [(20.0±1.5)μg/10⁷·h vs(36.5±4.4)μg/10⁷·h,P<0.05], and also could promote adhesion of PMNs-HUVEC(38.5±9.8 vs 61.0±4.4,P＜0.05). The expression of ICAM-1 mRNA was induced by nicotine in dose-dependent fashion (10^-5-10^-3mol/L).After a 2 h treatment of HUVEC with nicontine(10^-4mol/L), the level of ICAM-1 mRNA is above the control(1.23 vs 1.63) and the highest level (2.03) is at a 12 h treatment. 764-3 can obviously counteract the above effect of nicotine. CONCLUSIONS: Nicotine could activate PMNs, enhance adhesion of PMNs-HUVEC and increase the expression of ICAM-1 mRNA in HUVEC.     

Effect of transmyocardial laser revascularization on myocardial lactatic metabolism and mitochondria of myocardial cells

AIM: We studied the therapeutic effect and mechanism of transmyocardial laser revascularization (TMLR) for the acute myocardial ischemia (AMI). METHODS: 18 dogs were divided randomly and evenly into the control group, the AMI group and the TMLR group. A continuous wave Nd: YAG laser was used for TMLR. Concentration of lactate in artery and coronary sinus (A.Lat and CS.Lat), myocardial metabolic rate of lactate acid (MLR) and myocardial lactate extraction (MLE) were measured before the left anterior descending coronary artery (LAD) ligation and 60 min after the LAD ligation. Myocardial biopsy was made 4 h after the LAD ligation to quantitatively observe the shape and number of mitochondria in myocardial cells by a electric microscope. RESULTS: 60 min after the LAD ligation, CS.Lat were (7.63±4.27) mmol/L in the AMI and (5.78±3.98) mmol/L in the TMLR, respectively (P<0.05); MLR were (0.03±0.01) mmol·100 g^-1 myocardium·min^-1 in the AMI and (0.06±0.02) mmol·100 g^-1 myocardium·min^-1 in the TMLR, respectively (P<0.05); MLE were (12.04±3.04) in the AMI and (21.84±8.49)% in the TMLR, respectively (P<0.05). The volume density of mitochondria were (27.51±7.93)% in the AMI and (31.26±3.85)% in the TMLR, respectively (P>0.05). The area density of mitochondria were (1.25±0.18) μm^-1 in the AMI and (1.64±0.28) μm^-1 in the TMLR, respectively (P<0.01). The number density of mitochondria were (0.10±0.03) μm^-3 in the AMI and (0.18±0.05) μm^-3 in the TMLR, respectively (P<0.01). The average volume of mitochondria were (5.27±2.85) μm³ in the AMI and (2.80±0.54) μm³ in the TMLR, respectively (P<0.05). The average diameter of mitochondria were (2.06±0.36) μm in the AMI and (1.78±0.12)μm in the TMLR, respectively (P＜0.05). CONCLUSION: The study suggests that TMLR may effectively improve myocardial lactatic metabolism and protect the myocardial cells from ischemic injury in dogs with the AMI.     

Changes in human atrial myocyte dimension among different ages

AIM:To observe the changes in right atrial myocyte dimensions with myocardial development. METHODS: Cell length, width, length/width and cross-sectional area were measured in right atrial myocytes isolated from 12 weaning , 10 young , 13 adult human hearts. RESULTS: Cell length, width, length/width and cross-sectional area, at weanling group were (70.2±1.3) μm, (8.0±0.2) μm, (9.0±0.2) and (50.9±2.6) μm², respectively, at young group were (93.5±1.6) μm, (11.7±0.3)μm, 8.1±0.2, (109.7±5.8) μm², and (100.9±2.2) μm, (12.1±0.3) μm, 8.5±0.2, (119.0±5.5) μm² for adult group. Clearly, young myocyte lenght, width, cross-sectional area were greater than that of myocytes at weanling group(P＜0.01) but adult myocytes length/width and cross-sectional area increase slightly compared with young group. The length/width ratio has no significant change through myocyte maturity, which is between 8-9. CONCLUSIONS: Our data suggest that myocyte dimensions expect length/width ratio have increased progressively with maturity, the length/width ratio is preserved in atrial myocyte during the period of normal myocyte growth from weanling to adulthood, and these changes in myocyte dimensions are similar with ventricular myocytes changes from other mammalian species.     

Farrerol inhibits nicotine-induced proliferation of pulmonary vascular smooth muscle cells by enhancing Kv1.5 and Kv2.1 expression

AIM:To study the effect of farrerol (Far) on nicotine-induced proliferation of rat pulmonary smooth muscle cells (PASMCs), and further to explore its relationship with voltage-dependent potassium channels (Kv) 1.5 and Kv2.1. METHODS:Firstly, the effect of nicotine on the proliferation of PASMCs was detected by cell counting method, and the optimal concentration of nicotine was selected. Primary cultured PASMCs were randomly divided into 5 groups:normal control group, nicotine (1 μmol/L)group, nicotine (1 μmol/L) + Far (10^-6 mol/L, 10^-5 mol/L and 10^-4 mol/L) Far group. The activity of caspase-3 was measured by apoptosis kit, the cell viability was measured by CCK-8 assay, the apoptotic rate was analyzed by flow cytometry. The expression of Kv1.5 and Kv2.1, and apoptosis-related factors Bcl-2 and Bax at mRNA and protein levels was determined by RT-qPCR and Western blot respectively. RESULTS:Nicotine at 1 μmol/L increased the number of PASMCs to the maximum extent (P<0.01). Nicotine at 1 μmol/L significantly reduced the caspase-3 activity and enhanced the cell viability of the PASMCs (P<0.01). Farrerol at 10^-6~10^-4 mol/L eliminated the effect of PASMCs induced by nicotine in a concentration dependent manner. Compared with control group, nicotine at 1 μmol/L significantly increased the proliferation and inhibited the apoptotic rate of rat PASMCs (P<0.01). The apoptotic rate of PASMCs in farrerol intervention group was significantly higher than that in nicotine group (P<0.01). Nicotine at 1 μmol/L significantly inhibited the expression of Kv1.5, Kv2.1 and Bax but increased the expression of Bcl-2 in PASMCs (P<0.01). Farrerol at 10^-5 mol/L obviously inhibited the effect of PASMCs induced by nicotine. CONCLUSION:Farrerol eliminates nicotine-induced inhibition of caspase-3 and Bax, and enhancement of Bcl-2 in PASMCs by enhancing Kv1.5 and Kv2.1 expression.     

Effect of nicotine on systolic and diastolic function of rat aortic smooth muscle cells

AIM:To observe the effects of nicotine on systolic and diastolic function of rat aortic vascular smooth muscle cells (VSMCs). METHODS:The primary rat aortic VSMCs were cultured in vitro. After exposed to nicotine at different concentrations for 24 h, the cytoskeleton of the VSMCs was stained with rhodamine-phalloidin,the photographs of the VSMCs in different experimental groups were taken and the surface area was measured to reflect the cell contractility. Collagen contraction method was also used to determine the effect of nicotine on the contractility of rat aortic VSMCs. RESULTS:The primary rat aortic VSMCs were successfully cultured. After the VSMCs were treated with nicotine (0.1 μmol/L, 1 μmol/L, 10 μmol/L and 100 μmol/L) for 24 h, the skeleton showed a significant contraction, and the cell plate shape was obviously enhanced in a concentration-dependent manner. The results showed that 10 μmol/L was the optimal concentration of nicotine for VSMCs (P<0.01). The collagen contraction method also showed that 10 μmol/L nicotine contracted the rat aortic VSMCs. With the increase in the nicotine action time, the maximum contraction effect was observed at 60 min (P<0.01). CONCLUSION:Nicotine has a strong contractile effect on VSMCs of rat aorta, and its contractile effect is dependent on concentration and time.     

Effects of nicotine on ultrastructure and cytokine secretion of human periodontal ligamental fibroblasts

［ABSTRACT］AIM: To explore the effects of nicotine on surface morphology, ultrastructure, proliferation, cell cycle and cytokine secretion of human periodontal ligamental fibroblasts (PDLFs). METHODS: Before and after treatment with nicotine, the surface morphology and ultrastructure of PDLFs were observed under atomic force microscope and transmission electron microscope. The cell proliferation was examined by MTT assay. The cell cycle and apoptotic rate were determined by flow cytometry. The levels of basic fibroblast growth factor (bFGF), insulin-like growth factor I (IGF-I), transforming growth factor β1 (TGF-β1), intercellular adhesion molecule 1(ICAM-1), vascular cell adhesion molecule 1 (VCAM-1) and vasculr endothelial growth factor (VEGF) were detected by ELISA. RESULTS: After treatment with nicotine, pycnosis, vacuolation in the cytoplasm, and karyorrhexis were observed in the PDLFs. The rough endoplasmic reticulum expanded and mitochondria swelled. Cell proliferation was inhibited in a time- and dose-dependent manner. The cell number in G0/G1 phase increased while that in G2 phase and S phase decreased. The apoptotic rate and the rate of cycle arrest were increased with the increase in nicotine concentration. After treatment with nicotine, the secretion levels of bFGF and IGF-I declined, while the levels of ICAM-1, VCAM-1, TGF-β1 and VEGF increased. CONCLUSION: Nicotine changes the surface morphology and ultrastructure of PDLFs to apoptosis-like characters and inhibits the proliferation of the cells. Nicotine may affect the repairment of PDLFs by regulating the levels of cytokine secretion.     

优质大粒葡萄新品种'峰后'

从‘巨峰’的实生后代中选育出新品种‘峰后’,平均单粒质量12．78g,可溶性固形物含量17．87％,酸含量0．57％,口感甜、脆;果面鲜紫红色,果肉硬度0．5kg/mm^2;生长势强,抗病力强。     

Stable reversal of multidrug resistance in A549/DDP cells by shRNA targeting MRP1 gene

AIM: To reverse multidrug resistance (MDR) of A549/DDP cells with short hairpin RNA (shRNA) expression vectors. METHODS: Two multidrug resistance-associated protein 1( MRP1 ) gene-specific shRNA expression plasmids pSilencer 2.1-U6 neo-MRP1 were constructed and introduced into A549/DDP cells. MRP1 mRNA was assayed by real-time fluorescent quantitative PCR. The MRP1 function was determined by rhodamine 123(Rho123) retention and the protein expression of MRP1 was detected by immunofluorescent staining. The viability of A549/DDP cells was evaluated by MTT method. RESULTS: MRP1 shRNA expression plasmids were successfully constructed. The expression of MRP1 at mRNA and protein levels was significantly decreased after sh-MRP1-2.1-1 and sh-MRP1-2.1-2 were transfected into A549/DDP cells. The intracellular accumulation of Rho123 significantly increased from(16.93±0.58)% to (89.02±0.59)% and (82.56±1.37)%. IC₅₀ of cisplatin were decreased from (101.45±0.64) μmol/L to (38.06±0.05) μmol/L and (53.72±0.36) μmol/L. IC₅₀ of 5-fluorouracil were decreased from (263.20±2.00) μmol/L to (98.82±1.16) μmol/L and (141.81±0.49) μmol/L. CONCLUSION: The shRNA expression plasmid pSilencer 2.1-U6 neo-MRP1 can stably and permanently inhibit MRP1 gene. The sensitivity of A549/DDP cells to drug is reversed.     

Effect of G-CSF on the apoptosis induced by Ara-c in HL-60 leukemic cells

AIM: To observe the effects of methionine-induced hyperhomocysteinemia on protein C(PC), antithrombin-Ⅲ (AT-Ⅲ) and von willebrand factor (vWF).METHODS:The proliferat ion of HL-60 leukemia cell was observed by hemopoiet ic cell culture.Apoptosis was measured by the morphology of apoptosis cell, the quantitation of DNA fragmentation with the diphenylamine reaction.The change in drug sensitivity was measured by MTT.RESULTS:In group M, the levels of methionine(29.97±5.34 μmol/L) and homocysteine(13.30±2.19 μmol/L) in serum were signifficantly higher than those(14.48±1.97 μmol/L and 5.36±1.19 μmol/L, respectively, P＜0.01) of group C.The levels of AT-Ⅲ and PC of group M were signifficantly lower than those of group C (P＜0.01). The level of vWF in plasma of group M was higher than that of group C (P＜0.01). Immunohistochemistry showed that vWF expression in endothelial cells of aorta was decreased. CONCLUSION:Methionine-induced hyperhomocysteinemia had promotive effects on coagulation and inhibiting effects on antioagulation.     

Effects of airway epithelial cells on phenotype and phagocytosis of macrophages and roles of HIF-1α

AIM: To investigate the effects of airway epithelial cells on the phenotype and phagocytosis of macrophages and the roles of hypoxia-inducible factor-1α (HIF-1α).METHODS: Human bronchial epithelial (HBE) cells treated with CoCl₂ (0, 100, 200, 400 and 800 μmol/L) or transfected with HIF-1α siRNA were co-cultured with the macrophages differentiated from human monocyte line THP-1 induced by phorbol 12-myristate 13-acetate (PMA). The mRNA expression of HIF-1α in the HBE cells was detected by RT-qPCR. The expression of macrophage surface markers and the phagocytosis rate of E.coli by macrophages were analyzed by flow cytometry.RESULTS: CoCl₂ upregulated the mRNA expression of HIF-1α in the HBE cells in a concentration-dependent manner and peaked at 8 h. HBE cells treated with CoCl₂ increased the fluorescence intensity ratio of CCL3, CD163, CD206 and CCL18 in co-cultured macrophages, and the strongest effect was seen in the macrophages co-cultured with HBE cells treated with CoCl₂ at 800 μmol/L. The fluorescence intensity ratio of CCL3 in co-cultured macrophages increased most obviously at 8 h and 12 h, while the fluorescence intensity ratio of CD163, CD206 and CCL18 increased more prominently in the macrophages co-cultured for 24 h. The stimulating effects of the HBE cells transfected with HIF-1α-Homo-488 siRNA on CCL3, CD163, CD206 and CCL18 in the macrophages were significantly attenuated. The phagocytosis rate of E.coli by macrophages co-cultured with HBE cells treated with different concentrations of CoCl₂ for 24 h initially increased (up to 60 min), and then it gradually decreased. Compared with normal HBE co-culture group, the phagocytosis rate in 400 and 800 μmol/L stimulation groups decreased at each time point, and that in 800 μmol/L stimulation group was the most.CONCLUSION: In hypoxia environment, airway epithe-lial cells initially transform macrophages predominantly to an M1-phenotype. However, the long-term hypoxia-stimulated airway epithelial cells inhibit the phagocytosis of macrophages and convert them to M2 superiority. HIF-1α may be an important mediator in these processes.     

Effects of calcium channel blockers on nicotinic acetylcholine receptor current in rat chromaffin cells

AIM: To study the effects of calcium channel blockers (CCB) on nicotinic acetylcholine receptor current (I_NIC) in rat adrenal medullar chromaffin cells (RAMCs). METHODS: By using the whole-cell clamp-patch technique, we have investigated the effects of nifedipine(NIF)、ω-conotoxin GVIA and ω-agatoxin IVA on I_NIC induced by nicotine(NIC) before and after RAMCs perfusion. RESULTS: After perfusing RAMCs for 5 min, different kinds of calcium channel blockers at different concentration showed significant inhibitory effects on I_NIC induced by 50 μmol/L NIC. The peak inhibition rates of 10 μmol/L NIF、400 nmol/L ω-conotoxin GVIA and 100 nmol/L ω-agatoxin IVA were (61.7±5.1)%,(29.3±7.4)% and (17.6±7.5)%, respectively. CONCLUSION: The acute effects of different kinds of CCBs on RAMC were that they obviously inhibited I_NIC induced by NIC. These results suggest that CCBs may inhibit catecholamine secretion by directly blocking nicotinic acetylcholine receptor channel.     

Effects of hydrogen peroxide on sodium current in acutely isolated rat hippocampal CA1 neurons

AIM and METHODS: The effects of hydrogen peroxide on Na⁺ currents were studied in freshly dissociated rat hippocampal CA1 neurons using the whole-cell patch-clamp techinique. RESULTS: ①H₂O₂ caused a dose-dependent and voltage-dependent increase in the voltage-activated Na⁺ currents. The amplitudes of Na⁺ currents were increased (48.0±4.2)% and (88. 2±5. 1)% (n=10) by H₂O₂ at 10 μmol/L and 100 μmol/L, respectively. ②H₂O₂ (10 μmol/L) did not affect the activation process, but changed the inactivation process significantly. Before and after application of 10 μmol/L of H₂O₂, the half-inactivation voltage was (-64.58±1.22)mV and (-53.55±0.94)mV (n=10, P<0.01), but the slope factor was not changed. CONCLUSION: As a product of oxidation metabolism, H₂O₂ is related to some diseases in the central nervous system.     

Effect of lipopolysaccharide on viability and secretion function of human umbilical vein endothelial cells

AIM: To observe the direct effect of lipopolysaccharide (LPS) on secretion of endothelin-1 (ET-1) and nitric oxide by human umbilical vein endothelial cell and cell viability of the secretor. METHODS: The third passage of human umbilical vein endothelial cells were incubated with different concentrations of LPS (1 g/L, 100 mg/L, 10 mg/L, 1 mg/L, 100 μg/L, 10 μg/L, 1 μg/L) for 6 hours, and the culture supernatants were collected. The concentrations of ET-1 were determined by radioimmunoassay, the concentrations of nitric oxide were determined using Greiss's method. The viabilities of cells were measured by MTT method. RESULTS: The concentration of ET-1 (pg/L) of normal control group was 251.64±10.90. The concentrations of ET-1 (pg/L) of LPS treated groups were 220.85±19.14, 278.67±15.45, 306.40±11.60, 312.87±33.50, 324.38±17.02, 291.49±14.30, 282.11±13.38, respectively (each group compared with normal control group, P<0.05 or P<0.01). The concentration of NO_x (μmol/L) of normal control group was 629.46±13.36. The concentrations of NO_x (μmol/L) of LPS treated groups were 732.58±23.21, 669.87±9.32, 661.24±16.80, 650.33±13.24, 606.59±12.94, 626.75±9.83, 627.61±5.61, respectively (each group compared with normal control group, P<0.05 or P<0.01). The viabilities of endothelial cells of LPS treated groups were 74%, 81%, 86%, 88%,91%, 93%, 93%, respectively. CONCLUSION: LPS of lower concentrations had no significantly lethal effect on human umbilical vein endothelial cells, but enhanced secretion of ET-1 and inhibited NO production. LPS in higher concentrations showed significant lethal effect on human umbilical vein endothelial cells, inhibited secretion of ET-1 and enhanced NO production.     

Inhibition of miR-9 expression suppresses proliferation,invasion and migration of nasopharyngeal carcinoma cells

AIM: To investigate the effects of down-regulated miR-9 expression on the proliferation, invasion and migration of nasopharyngeal carcinoma (NPC) cells. METHODS: Human NPC CNE1 and CNE2 cells were transfected with the inhibitor of miR-9 by Lipofectamine to down-regulate the expression of miR-9, and the cells transfected with an inhibitor control were also set up. The cell proliferation and cell cycle were evaluated by CCK-8 assay and flow cytometry. The cell invasion and migration abilities were detected by Transwell invasion and wound-healing assays. Immunoblotting was applied to analyze the levels of the proteins. RESULTS: Compared with control group, inhibition of miR-9 expression in the NPC cells by transfection of the miR-9 inhibitor significantly decreased the proliferation ability (P<0.05). The percentages of the cells in G0/G1 phase ［CNE2: (57.96±1.39)% vs (47.93±1.76)%, P<0.05; CNE1: (51.24±0.88)% vs (48.29±0.39)%, P<0.05］ were significantly increased. The migration distances ［CNE2: (186.50±7.94)μm vs (247.56±15.56)μm, P<0.05; CNE1: (139.06±16.73)μm vs (230.66±14.27)μm, P<0.01］ and the invasion ability of the CNE2 cells (43.00±3.17 vs 65.80±5.20, P<0.01) were also significantly inhibited. Moreover, the tumor cells transfected with the inhibitors produced lower β-catenin. CONCLUSION: Inhibition of miR-9 expression suppresses the proliferation, invasion and migration of nasopharyngeal carcinoma cells.     

Effect of berberine on endoplasmic reticulum stress-autophagy pathway in human ovarian cancer SKOV3 cells

AIM: To investigate the regulatory effect of berberine on the endoplasmic reticulum stress-auto-phagy pathway in human ovarian cancer SKOV3 cells. METHODS: Human ovarian cancer SKOV3 cells were cultured in vitro, and berberine at doses of 12.5, 25, 50, 100, 200 and 400 μmol/L were added. After exposure for 12 h, 24 h and 48 h, the viability of the SKOV3 cells was measured by MTT assay. The cells were divided into control group, berberine (50 μmol/L) group, berberine (100 μmol/L) group, and berberine (200 μmol/L) group. After treatment with berberine for 24 h, the effects of berberine on the morphological changes of SKOV3 cells were observed under inverted phase-contrast microscope. The protein expression of microtubule-associated protein 1 light chain 3 (LC3) and ubiquitin-binding protein p62 was observed by indirect immunofluorescence method under laser confocal microscope. The protein expression of beclin-1,LC3,p62, CCAAT/lenhancer binding protein homologous protein (CHOP) and glucose-regulated protein 78 (GRP78) was determined by Western blot. RESULTS: Berberine at 12.5, 25, 50, 100, 200 and 400 μmol/L significantly decreased the viability of SKOV3 cells at 12 h, 24 h and 48 h, and the IC₅₀ values of 12 h, 24 h and 48 h were (764.7±0.3) μmol/L, (231.6±0.1) μmol/L and (96.2±0.1) μmol/L, respectively. Laser confocal microscopy showed that the LC3 and p62 proteins were scattered and the fluorescence intensity was increased, while the point-like aggregation was also observed. Berberine at 200 μmol/L obviously enhanced the co-localization of LC3 and p62 proteins. Compared with control group, the expression of endoplasmic reticulum stress-related proteins GRP78 and CHOP, and autophagy-related proteins beclin-1, LC3 and p62 in berberine (200 μmol/L) group was increased significantly (P<0.05). CONCLUSION: Berberine may promote endoplasmic reticulum stress in SKOV3 cells by regulating autophagy.     

Metallothionein protects rat hepatic nuclear nucleoside triphosphatase from hydroxyl radical-induced suppression

AIM:Metallothioneins (MTs) are cysteine-rich metal-binding proteins that exert cytoprotection during metal exposure and oxidative stress. The present study was designed to investigate whether MT can directly protect NTPase on nuclear envelope from damage induced by hydroxyl radical.METHODS:Isolated hepatic nuclei from rat liver were exposed to Fe²⁺/H₂O₂ with or without MT, and the NTPase activity on nuclei was assayed using ATP and GTP as substrate, respectively.RESULTS:Incubation of rat hepatic nuclei with the Fe²⁺/H₂O₂ (in μmol·L^-1/μmol·L^-1 : 0.1/0.5, 0.5/2.5, 1/5, 5/25) resulted in a concentration-dependent decrease in nuclear NTPase activities (P＜0.01). Incubation of hepatic nuclei with different concentrations of MT (10^-9-10^-4mol·L^-1)and Fe²⁺/H₂O₂ (1 μmol·L^-1/5 μmol·L^-1) for 10 min, nuclear NTPase activities were increased in a MT concentration-dependent fashion as compared with that of incubation with Fe²⁺/H₂O₂(1 μmol·L^-1/5 μmol·L^-1) alone. When MT was at 10^-4 mol·L^-1, TNPase activities reversed to (102±10) nmol·mg^-1 protein·min^-1(for ATP as substrated) and (131±12) μmol·g^-1 protein·min^-1(for GTP as substrate), which had no significant defferences from that of the controls (112±8 and 142±10 μmol·g^-1 protein·min^-1, respectively) (P＞0.05). In addition, incubation of hepatic nuclei with only MT had no effect on nuclear NTPase activity. CONCLUSION:These data demonstrate that hydroxyl radical generated from Fe²⁺/H₂O₂ might attack nuclear NTPase. MT antagonistically reduces toxicity of Fe²⁺/H₂O₂ system to the NTPase.     

Correlation between post-operation insulin resistance and intestinal barrier dysfunction in obstructive jaundice rats

AIM：To investigate the correlation between post-operation insulin resistance (IR) and intestinal barrier dysfunction in obstructive jaundice (OJ) rats. METHODS：The rat model of OJ was set up. The rats were randoml divided into control group (sham operation), OJ group, glucagon-like peptide 2 (GLP-2) group (challenged with GLP-2 by intraperitoneal injection) and insulin group (insulin subcutaneous injection). Peripheral blood was collected 1 d before operation and 2 h, 24 h, 48 h, 3 d and 7 d after operation. The IR index and the ratio of lactulose/mannitol (L/M) were determined. The concentration of serum resistin-like molecule (RELM) β was detected by ELISA. The relative mRNA level of RELMβ in terminal ileum enterocytes was measured by semi-quantitative RT-PCR. RESULTS：The IR index and the ratio of L/M in OJ group 3 d after operation were 10.1±1.8 and 0.66±0.08, respectively, which were higher than those at other time points (all P<0.05). The correlation coefficient between the changes of IR index and ratio of L/M was 0.86 (P<0.05). The IR index in GLP-2 group descended by 37.0% 7 d after operation (7.33±1.07 vs 4.62±0.53, P<0.05). The highest concentration of serum RELMβ was observed in OJ group 3 d after operation (0.69 μg/L±0.05 μg/L). The relative mRNA level of RELMβ in terminal ileum enterocytes was also increased obviously. The expression of RELMβ was obviously decreased in GLP-2 group and insulin group. CONCLUSION：There is closed relationship between post-operation insulin resistance and intestinal barrier dysfunction. The RELMβ is the point of intersection. Enterocytes are not only the source of post-operation insulin resistance but also the target organ.     

Effects of docosahexaenoic acid on large-conductance calcium-activated potassium channels in rat pulmonary artery smooth muscle cells

AIM：To investigate the effects of docosahexaenoic acid (DHA) on large-conductance calcium-activated potassium channels (BKCa) in rat pulmonary artery smooth muscle cells (PASMCs)．METHODS：BKCa currents in individual PASMCs were recorded by patch-clamp technique in whole-cell configuration．Calcium sparks in PASMCs caused by DHA were recorded by confocal microscopy. RESULTS：DHA activated BKCa . BKCa current densities were (30.5±6.5)pA/pF,(59.4±5.8)pA/pF, (87.2±4.3)pA/pF and (117.3±7.1) pA/pF (P<0.01) with the addition of DHA at concentrations of 0, 0.1, 1 and 10 μmol/L, respectively. Hypoxia inhibited BKCa currents in PASMCs, but this inhibition was reversed by DHA (10 μmol/L). DHA (10 μmol/L) induced an increase in ［Ca2+］i with a maximal increase rate of (71.9±4.1)%. CONCLUSION：DHA activates BKCa in rat PASMCs, leading to the vasodilation of pulmonary arteries.     

Dynamic changes of the concentration of nitric oxide in ischemic myocardium and its mechanism

AIM: The study was undertaken to explore the dynamic changes of the concentration of nitric oxide(NO) in ischemic myocardium and its mechanism.METHODS: In vivo myocardial ischemia of mice and in vitro perfused isolated heart of rat were used in the experiment. The effects of severity and time of ischemia on NO production, NOS activity and mRNA were examined, respectively. RESULTS: There was a considerable difference (P<0.01) in the concentration of NO between ischemia group [(9.12±1.40) μmol/L] and control group [(20.16±1.67) μmol/L] after Pit(30 U/kg) administration, and the concentration of NO of ischemic group significantly decreased [(9.17±1.33) μmol/L] compared with control group [(19.90±1.95) μmol/L] after 30 minutes of ischemia. Also, the concentration of NO after Pit(20 U/L) administration in K-H and 15 min of ischemia was (15.41±2.00) μmol/L and (15.09±2.00) μmol/L respectively in vitro, significantly lower than control group [(23.83±2.33) μmol/L and (23.63±2.52) μmol/L]. In addition, compared with control group, the number of NOS positive cells, NOS activity as well as mRNA expression in atrial muscle and ventricular muscle of ischemic group were markedly reduced, respectively. CONCLUSION: Myocardial ischemia could reduced the NO level in myocardium, down-regulation of NOS mRNA could be the possible mechanism.