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Objective To evaluate the differentiation of mouse tracheal epithelial cells ( MTEC) at an air-liquid interface and to investigate the influences of influenza virus on the cystic fibrosis transmem-brane conductance regulator ( CFTR) in primary cultured MTEC for further elucidating the possible mecha-nism of imbalanced fluid and salt transportation in respiratory system caused by influenza virus infection . Methods The morphology of primarily cultured MTEC was observed under inverted microscope .Trans epi-thelial electrical resistance ( TEER) was measured by a resistance meter to evaluate the integrity of cultured MTEC.An Ussing chamber apparatus was used to record the short-circuit current of primary cultured MTEC . Results The primarily cultured MTEC clustered together and had a tight pavement-like appearance under light microscope .The TEER was greater than 1000 Ωafter 6 days of culture .Influenza virus could reduce the short-circuit current of CFTR to (52.77±10.30)％in intact cell membrane and to (41.50±1.09)％in monolayer MTEC after increasing the permeability of basement membrane .It had been proved that CFTR was essential to maintaining the balance of fluid and salt transportation in respiratory system.Conclusion Mouse MTEC are efficiently cultured at a air-liquid interface and the primarily cultured cells are highly simi-lar to those in a normal physiologic state .Influenza virus may block the secretion of anions through inhibiting the function of CFTR , which may induce the development of chronic obstructive pulmonary disease and the incidence of asthma .
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Aim Bupivacaine is a kind of long-acting amide local anesthetics.This paper aims to explore the effects of bupivacaine on the short-circuit currents in human alveolar epithelial monolayers and study the possible mechanisms.Methods Short-circuit currents were recorded by ussing-chamber setup.Amiloride-sensitive currents were defined as the difference be-tween the total current and the amiloride-resistant cur-rent.ERK1 /2 phosphorylation protein levels were ana-lyzed by Western blot at 0,1 5,30 and 60 min after administration of 1 00 μmol·L -1 bupivacaine.Results Bupivacaine could inhibit the short-circuit currents in H441 monolayers dose-dependently,which could be inhibited by amiloride.Western blot analysis showed that bupivacaine increased the level of ERK1 /2 phos-phorylation.Conclusion These data demonstrate that bupivacaine can reduce the alveolar ion transport by in-hibiting the amiloride-sensitive currents,possibly by the enhancement of ERK1 /2 phosphorylation. The effects of alveolar fluid clearance following application of bupivacaine should be considered clinically when the patient is complicated with lung injury.
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Objective To explore the relationship between 1,25-dihydroxyvitamin D3(1,25-VD3)and alveolar fluid clearance(AFC)in mice in vivo,and investigate its effects in the process of lung fluid clearance. Methods KM male mice were treated with active vitamin D analogue parical-citol(daily i.p. injection)for 2 weeks,and then the in vivo AFC of these mice was measured by bovine serum albumin protein assays. western blot was applied to determine epithelial sodium channel protein levels in lungs of these mice. Results In vivo total AFC was 31.9%±3.8%in vitamin D-treated mice,and significantly lower in the vehicle-treated controls(19.7%±1.9%,P<0.05). Amiloride-sensitive AFC was increased approximate-ly 50%by vitamin D. western blot showed that the expression ofα-epithelial sodium channel was significantly elevated in paricalcitol-treated mouse lungs. Conclusion These observations suggest that vitamin D augments AFC in mice,which may be related to the augment of epithelial sodium channel protein expression. The clinical application of vitamin D therapy may ameliorate pulmonary edema of patients.
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Aims To extract,separate and identify the flavonoid constituents in Humulus Scandens and to ex-plore the relationship of monomers and alveolar fluid clearance (AFC)in mice in vivo.Methods Humulus scandens were extracted with alcohol and then isolated by the technology of Column and the structures were i-dentified by spectrometry.In vivo AFC was measured using bovine serum albumin protein assays affected by luteolin-7-O-β-D-glucoside (LGL ) and cosmsiin (AGL).Results The main constituents of flavanones in Humulus scandens were LGL and AGL.Both of them could improve the AFC.Conclusion The AFCs of LGL and AGL,compared to the blank control group, increased which explains the effect of flavonoid constit-uents on removing edema and promoting water absorp-tion.
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Objective To investigate the effect of hyperoxia on the expression and transport function of epithelial sodium channel (ENaC) in neonatal rat alveolar epithelial type Ⅱ(AT Ⅱ) cells.Methods AT Ⅱ cells were isolated from neonatal rats,and primarily cultured under hyperoxic or normoxic conditions.Western blot was applied to examine the ENaC expression,and the amiloride-sensitive Na + currents were recorded using the whole-cell patch clamp technique.Results Hyperoxia upregulate the expression of β-ENaC and γ-ENaC subunits in the neonatal rat ATⅡ cells(β-ENaC:1 d:0.43 ±0.06 vs0.32 ±0.04,P =0.047;2 d:0.73±0.06 vs 0.50±0.08,P =0.019;3 d:0.72 ±0.08 vs 0.52 ±0.06,P =0.027;γ-ENaC:1 d:0.64±0.05 vs0.53 ±0.05,P =0.044;2 d:0.76 ±0.03 vs 0.52 ±0.04,P =0.001 ;3 d:0.77 ±0.06 vs 0.61 ±0.05,P =0.025).In addition,the amiloride-sensitive Na+ currents in hyperoxia-exposed AT Ⅱ cells were also increased (1d:13.71 ±2.77 vs8.92±1.38,P＜0.001;2d:29.12±11.03 vs 10.41 ±1.80,P＜0.001),which was consistent with the upregulated expression of β-ENaC and γ-ENaC.However,the expression of α-ENaC was inhibited by hyperoxia to some extent (1 d:0.31 ± 0.05 vs 0.46 ± 0.05,P =0.025 ; 2 d:0.30 ±0.01 vs0.38±0.02,P=0.002;3d:0.37±0.06 vs 0.37 ± 0.08,P =0.983).Conclusion Hyperoxia enhanced the transport function of ENaC in neonatal rat AT Ⅱ cells.Dysfunctional transport of Na + may not be a key factor involving in pulmonary edema at the early stage of bronchopulmonary dysplasia.
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AIM To investigate the effect of ke tamine on ATP-sensitive K + currents (I K ATP ) in single airway smooth muscle (ASM) cells of asthmatic rat. METHODS Single ASM cells of asthmatic rat were isolated with enzymatic dissociation technique. Effect of ketamine on I K ATP in single ASM cells was studied using the whole-cell configu ration of patch clamp technique. RESULTS Ketamine opened the ATP -sensitive K + channel (K ATP channel) in a dose-dependent manner. When the concentrations of ketamine were 1?10 -7 ,1?10 -6 ,1?10 -5 and 1?10 -4 mol?L -1 , the amplitude values of I K ATP were increased to 63 86?19 33 pA/pF(n=8,P
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Objective To investigate the effect of carboxymethyl chitosan on sodium currents (I_(Na)) in single ventricular myocyte of rat,and to explore the mechanism of carboxymethyl chitosan at the ionic channel level.Methods Single ventricular myocyte of rat was isolated with enzymatic dissociation technique.Whole-cell patch clamp technique was used.The stimulating protocol was:holding potential—120 mV,command potential—80 mV to +20 mV,step potential 10 mV,duration 50 ms,stimulating interval 2 s.Results Carboxymethyl chitosan inhibited sodium channel in a dose-dependent manner.When holding potential was—120mV,carboxymethyl chitosan(0.1%,0.2%,0.3%) decreased the peak amplitude of I_(Na) density to 57.4%?6.7%,40.9%?5.4%and 16.1%?4.3%(P
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Objective: To observe influence of hypotension induced with diethylamine(DEA)on oxygen delivery (DO_2), oxygen consumption (VO_2)and the concentration of lactate. Method: Twelve healthy adult dogs were randomly assigned into one of the two groups. 0.001% DEA or 0.0l% sodium nitroprusside (SNP) was infused to induce mean arterial pressure(MAP) to decrease to 60% of baseline and maintaine for 30 min. During hypotension, MAP and HR were recorded. Arterial and mixed venous blood gas, and blood lactate level were measured. Result: There were no sig nificant changes in DO_2. VO_2, oxygen extraction ratio and blood lactate level in both groups. The concentration of lac tate was not increased in either group. Conclusion. The oxygen metabolism may not be affected during DEA-induced hypotention
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Objective To investigate the effect of carboxymethyl chitosan on ATP-sensitive K+ currents(IKATP) in single ventricular myocyte of rat.Methods Single ventricular myocyte of rat was isolated with enzymatic dissociation technique.Whole-cell patch clamp technique was used.The stimulating protocol was:holding potential-40 mV,command potential-100 mV to +50 mV,step potential + 10 mV,duration 200 ms,stimulating interval 6 s.Results Carboxymethyl chitosan inhibited the ATP-sensitive K+ channel(KATP channel) in a dose-dependent manner.When holding potential was-60 mV and stimulating potential was + 50 mV,carboxymethyl chitosan(0.1%,0.2%,0.3%) decreased the amplitude values of IKATP to 66.1%?9.9%,50.3%?13.3%and 39.8%?9.5%(n=7)of control,respectively.The changes of IKATP under other command potentials were consistent with this.Conclusion Carboxymethyl chitosan inhibits KATP channel in single ventricular myocyte of rat in a dose-dependent manner,and may be one of the mechanisms of antiarrhythmia.
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Aim To study effects of vigabatrin on absence-like seizures and tonic convulsions in spontaneously epileptic rats (SERs). Method Electrcorticogram and depth electroencephalographic activity in hip- pocampus of SERs were recorded with implanted electrodes after administration of vigabatrin. Results The number of absence-like seizures was significantly reduced from 100% to (54?5)%, (41?9)% and (34?4)% (P