Effect of calmodulin inhibitors on viability and mitochondrial potential of Plasmodium falciparum in culture.

Calmodulin inhibitors are toxic for a variety of protozoa. Chlorpromazine, calmidazolium, and trifluoperazine inhibited the incorporation of [3H]hypoxanthine and [3H]phenylalanine into Plasmodium falciparum organisms in cultures with 50% inhibitory concentrations varying from 5.1 microM (with calmidazolium) to 48 microM (with chlorpromazine), the former being more sensitive than the latter. However, these concentrations also immediately dissipated rhodamine 123 from the parasite mitochondrion. Similar concentrations inhibit other protozoa, as well as mammalian cells, and the possibility that mitochondrial function rather than that of calmodulin is the target of these drugs should be considered.     

Regulation of the number of functional voltage-sensitive Ca++ channels on PC12 cells by chronic changes in membrane potential

The properties of the various types of voltage-sensitive Ca++ channels (VSCC) are becoming increasingly well characterized, but the mechanisms which control the number and types of channels expressed by cells are virtually unknown. To study the regulation of VSCC in neuronal cells we have used PC12 pheochromocytoma cells. Binding of [3H]nitrendipine was used to determine the number of dihydropyridine-sensitive channels, and the uptake of 45Ca++ was used to determine the functional state of VSCC on the cell surface. Prolonged depolarization by elevation of extracellular K+ caused concomitant time and concentration-dependent decreases in both [3H]nitrendipine binding and depolarization-dependent uptake of 45Ca++. Changes in binding and ion flux plateaued at about a 50% decrease with 3 days of depolarization and an extracellular K+ concentration of 50 mM. Return of the cells to normal K+ caused the recovery of both [3H]nitrendipine binding and 45Ca++ uptake within 24 hr. Measurements of the intracellular free Ca++ concentration determined that it remained elevated for several hours with K+ depolarization, but returned to normal within 15 hr. Growth of the cells with a concentration of ionomycin, which caused a similar increase in intracellular free Ca++, also caused a loss of [3H]nitrendipine binding sites. Thus, it appears that the number of functional VSCC can be regulated by changes in intracellular Ca++ such as those associated with prolonged depolarization. However, because Ca++ channel number remained depressed while intracellular free Ca++ returned to normal, other mechanisms controlling channel number also must be involved.     

Loss of mitochondrial membrane potential is inhibited by bombesin in etoposide-induced apoptosis in PC-3 prostate carcinoma cells

Neuroendocrine secretory products and their interactions with epithelial prostate cells are currently under investigation in order to understand their significance in the pathogenesis, prognosis, and therapy of prostate carcinoma. These neuropeptides have the potential to disrupt the balance between cell death and cell growth in the tumor. Our research was based on the role of bombesin in modulating the mitochondrial membrane potential (Delta psi(m)) in cell death induced by etoposide on PC-3 cells. Cells were cultured and stained with 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolylcarbocyanine iodide (JC-1). At low membrane potentials, JC-1 produces a green fluorescence, and at high membrane potentials, it forms "J aggregates" with red fluorescence. Cells were examined in a confocal microscope. For quantitative analyses, regions of interest were selected. The size, number of pixels, and ratios between fluorescence intensity in the red and green channels in each region of interest were calculated. The loss of Delta psi(m) in etoposide-treated PC-3 cells was prevented by bombesin. The quantitative analysis of JC-1-stained cells revealed a significant decrease in the red (high Delta psi(m)) to green (low Delta psi(m)) ratio in etoposide-treated cells when compared with control cells, which was restored in the presence of bombesin (P < 0.00001). The interaction between treatments and area (P = 0.0002) was highly significant, and confirms that PC-3 cells keep their apoptosis machinery, showing an apoptotic volume decrease in response to etoposide. The protection by bombesin occurs by inhibition of apoptosis and maintenance of mitochondrial integrity. New therapeutic protocols and trials need to be developed to test drugs acting through the neutralization of antiapoptotic intracellular pathways mediated by neuroendocrine hormones.     

谷氨酰胺对白细胞介素-1β刺激下大鼠肝细胞一氧化氮的产生及线粒体膜电位的影响

目的 利用原代培养的大鼠肝细胞,观察不同浓度的谷氨酰胺(Glutamine,Gin)在体外对白细胞介素-1β(Interleukin-1β,IL-1β)刺激下肝细胞一氧化氮(Nitric oxide,NO)过度产生和线粒体膜电位降低的影响.方法 选用6周龄SD大鼠,采用原位胶原酶循环灌注消化法获取高纯度原代大鼠肝细胞,培养48 h后分别用生理盐水、IL-1β(1 nmol/L)以及IL-1β(1 nmol/L)联合不同浓度的Gln(2 mmol/L、5 mmol/L、10 mmol/L)刺激肝细胞24 h,留取细胞和上清液,采用生化法测定上清液丙氨酸转移酶(lanine aminotransfemse ALT)和NO的水平,采用荧光探针Jc-1结合流式细胞仪检测肝细胞线粒体膜电位的变化.对各组数据之间进行方差分析,明确是否具有统计学意义.结果 IL-1β刺激后肝细胞培养液ALT平均浓度为38.2 U/L、N0的平均浓度为72.7 umol/L,均显著高于生理盐水组(分别为7.4U/L和41.7 mnol/L,P<0.01),而肝细胞线粒体膜电位水平却明显低于生理盐水组(强红色荧光细胞比例分别为30.0%和62.8%,P<0.01);同时给与Gln能够抑制IL-1β刺激下肝细胞N0的产生,减轻ALT的升高以及线粒体膜电位的降低,并且这些作用随着Gln浓度的增加而增强.结论 谷氨酰胺对炎症应激导致的肝细胞损伤具有保护作用,这种保护作用可能与抑制肝细胞NO的过度产生改善线粒体呼吸功能有关.     

Effect of chronic administration of verapamil on Ca++ channel density in rat tissue.

The purpose of this study was to determine if chronic administration of verapamil could alter the density of Ca++ channels in the heart as determined by [3H]PN 200-110 binding. Initially, we compared the effects of verapamil given by s.c. injection or via implantable, slow-release verapamil pellets. We found the majority of animals treated with the pellets died within 24 hr. Those that survived exhibited significantly depressed maximal binding and Kd values for PN 200-110 binding to cardiac membranes, but binding to brain membranes was unaffected. Quantitation of the serum levels of verapamil and its metabolites by high-performance liquid chromatography demonstrated that the verapamil pellets did not release the drug evenly over a 3-week period. Most of the drug was released in toxic quantities during the 1st day after implantation. Verapamil administered by injection (2.5-30 mg/kg/day) for up to 16 weeks raised plasma verapamil levels to 25 to 250 ng/ml, but had no effect on Ca++ channel characteristics in cardiac or brain tissue. The maximal binding and Kd values for skeletal muscle PN 200-110 binding were increased only at the highest dosage for 8 weeks duration. Our results demonstrate that implantable pellets are not a reliable administration method for verapamil and cardiac Ca++ channels are highly resistant to change during chronic verapamil administration.     

Effect of reserpine pretreatment on calcium transport and Ca++-Mg++ adenosine triphosphatase activity of guinea-pig cardiac microsomes

A previous report from this laboratory showed that reserpine pretreatment, in appropriate doses and under restricted conditions, increased the inotropic responsiveness of guinea-pig hearts to calcium. The enhanced responsiveness was characterized by a selective increase in the rate of ventricular relaxation (-dP/dt). We therefore hypothesized that reserpine might alter calcium uptake or (Ca++-Mg++) adenosine triphosphatase (ATPase) activity of guinea-pig ventricular sarcoplasmic reticulum (SR). Pretreatment of guinea pigs with reserpine (2.5 mg/kg/day, 2 days) significantly elevated ATP-dependent, Tris oxalate-facilitated SR Ca++ uptake and increased the calcium-sensitive component of the SR (Ca++) ATPase activity. These changes appeared to be functionally related to a reserpine-induced potentiation of ventricular relaxation rate, as estimated by the relationship between negative and positive left ventricular dP/dt of isolated working guinea-pig hearts. An alternative dose of reserpine (5 mg/kg, -24 hr), which had been demonstrated to produce an equivalent degree of catecholamine depletion, had no effect on either the inotropic responsiveness to calcium or on the SR calcium uptake or ATPase activities. The exact mechanism for these reserpine-induced alterations in calcium homeostasis remains to be elucidated.     

Effect of forskolin on cytosolic Ca++ level and contraction in vascular smooth muscle

The effects of forskolin, an activator of adenylate cyclase, on cytoplasmic Ca++ level ([Ca++]cyt) measured simultaneously with muscle tension using fura-2-Ca++ fluorescence were examined in isolated smooth muscle of rat aorta. Forskolin decreased muscle tension and [Ca++]cyt in resting aorta whereas both norepinephrine and high K+ solution produced sustained increase in muscle tension and [Ca++]cyt. Addition of forskolin during the sustained contractions decreased muscle tension more strongly than [Ca++]cyt. Norepinephrine-induced contraction was more sensitive to forskolin than high K+-induced contraction. The inhibitory effect of forskolin was attenuated when the concentration of norepinephrine or K+ was increased. Cumulative addition of norepinephrine or K+ induced a concentration-dependent increase in both [Ca++]cyt and muscle tension and a positive [Ca++]cyt-tension correlation was observed. In the presence of 0.1 microM forskolin, the norepinephrine-induced increments in [Ca++]cyt and muscle tension were inhibited without changing the [Ca++]cyt-tension relationship. In the presence of a higher concentration (1 microM) of forskolin, muscle tension was inhibited more strongly with only a small additional decrease in [Ca++]cyt resulting in a shift of the [Ca++]cyt-tension relationship. Norepinephrine induced transient increments in [Ca++]cyt and muscle tension in Ca++-free solution and forskolin inhibited these changes. These results suggest that forskolin has concentration-dependent inhibitory effects on vascular contractility to decrease [Ca++]cyt at lower concentrations and to decrease the sensitivity of contractile elements to Ca++ at higher concentrations.     

Effects of milrinone on Ca++-sensitivity of myofibrillar Mg-adenosine triphosphatase isolated from normal human and canine hearts

Sensitization or desensitization of cardiac actomyosin to calcium has been demonstrated with several pharmacological agents. The effect of milrinone on the sensitivity of cardiac Mg-adenosine triphosphatase (ATPase) activity to calcium was studied in purified myofibrils isolated from normal human hearts (after accidental death or trauma that caused no cardiac damage as established by the attending physician) and from normal canine hearts (established by echocardiography), over a range of calcium concentrations (pCa, 8 to 5). Caffeine, a cardiac stimulant that has been shown to increase the sensitivity of myofibrillar Mg-ATPase activity to calcium in rat ventricle, was used in this study to establish its effect on canine and human myofibrils in comparison with that of milrinone. Caffeine, at concentrations of 40 mM, caused statistically significant sensitization of canine and human myofibrils to calcium. In canine myofibrils, the calcium-dependent Mg-ATPase activity increased from 11.0 +/- 1.2 to 18.8 +/- 2.6 nmol of Pi per mg of protein per min at pCa 6.73 (N = 9, P less than .05) and from 32.9 +/- 2.1 to 37.3 +/- 2.2 nmol of Pi per mg of protein per min at pCa 6.16 (N = 9, P less than .05), whereas total Mg-ATPase activity increased from 23.4 +/- 1.5 to 33.6 +/- 2.6 nmol of Pi per mg of protein per min at pCa 6.73 (N = 9, P less than .05) and from 45.2 +/- 2.2 to 52.2 +/- 2.5 nmol of Pi per mg of protein per min at pCa 6.16 (N = 9, P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of dihydrostreptomycin on active transport in isolated bacterial membrane vesicles.

Membrane vesicles prepared from bacterial cells grown in the absence of dihydrostreptomycin but subsequently incubated in the presence of dihydrostreptomycin transported proline normally, but vesicles prepared from cells grown in media to which dihydrostreptomycin was added 30 min before harvesting had a greatly impaired ability to accumulate proline. The latter cells extruded protons normally but were unable to maintain a proton gradient as effectively as normal cells. These data indicated that metabolism was required for dihydrostreptomycin to exert an effect on the bacterial cell membrane.     

Effect of palytoxin on membrane and potential and current of frog myelinated fibers.

Palytoxin is a highly toxic compound isolated form several zoanthid Palythoa species. The effects of palytoxin on the nodal membrane of frog myelinated fiber have been studied under current clamp and under voltage clamp conditions. Under current clamp conditions, palytoxin (0.1 microng/ml, 3 x 10(-8)M) induces a depolarization which is not reversed by washing. The resting potential reaches a value of -35 mV after 10 minutes. During the same period, the evoked action potential shows a gradual decline and finally disapears after about 30 minutes. The membrane depolarization is suppressed by removal of Na ions from the external medium, but only slightly diminished when tetrodotoxin (10(-6)M) is subsequently added to the external medium. When the potential of the nodal membrane is maintained at -70 mV, palytoxin (0.1 microng/ml) causes the appearance of an inward current that increases in magnitude during 30 minutes before attaining a steady-state value. The kinetics of development of that current is modified in the presence of tetrodotoxin or saxitoxin. Voltage clamp analysis shows that palytoxin causes an increase of the resting sodium permeability that is accompanied by a shift of the voltage dependence of the transient sodium permeability in the direction of membrane hyperpolarization. The shift in the voltage dependence of the transient permeability is accompanied by a decrease of the peak transient permeability. A similar shift in the potential dependence of the sodium inactivation is observed. During and after the application of palytoxin, the internal sodium concentration increases. The steady-state (potassium) conductance is also decreased at the same time as the leak current is increasing.     

Effect of ethanol and metabolic substrates on the oxidation of aminopyrine, formaldehyde and formate by isolated hepatocytes

The production of [14C]O2 from 14C-labeled aminopyrine involves the following sequence: Aminopyrine 1 leads to formaldehyde 2 leads to formate 3 leads to CO2 Ethanol has the potential to affect any of the above steps in this sequence. In isolated hepatocytes from fasted rats ethanol inhibited CO2 production from aminopyrine, but not from formaldehyde or formate. Significant inhibition was found at low levels of ethanol that do not affect aminopyrine metabolism by isolated microsomes. There was only a slight accumulation of formaldehyde and formate during the oxidation of aminopyrine to CO2, both in the absence or presence of ethanol. This suggests that step I is the rate-limiting step and the step most sensitive to ethanol. There was accumulation of formate during the oxidation of formaldehyde to CO2. Ethanol decreased this formate accumulation suggesting some inhibition of the overall rate of formaldehyde oxidation. Addition of pyruvate, lactate, fructose, xylitol and sorbitol increased the rate of CO2 production from aminopyrine, but not from formaldehyde or formate. This increase by the substrates is probably due to an increase in the availability of NADPH required for step I. There was a slight increase in the accumulation of formaldehyde or formate during the oxidation of aminopyrine to CO2 in the presence of the substrates. Pyruvate and fructose nearly completely prevented the inhibition of CO2 production from aminopyrine by ethanol. Partial prevention was noted with the other substrates. Reduction of the cellular redox state as a consequence of ethanol metabolism may interfere with the transport of NADPH out of the mitochondria and, consequently, decrease the availability of NADPH for step I.(ABSTRACT TRUNCATED AT 250 WORDS)     

赤芍总苷诱导K562细胞凋亡及对线粒体膜电位和Ca2+的影响

目的:赤芍总苷能诱导鼠HepA和S180细胞凋亡,但赤芍总苷能否抑制K562细胞增殖及其诱导K562细胞凋亡的机制尚不明确.观察赤芍总苷诱导人红白血病细胞株K562细胞凋亡及线粒体膜电位与Ca2 水平的变化,以探讨凋亡机制.方法:实验于2007-03-02/2007-10-20在北京中医药大学细胞生化实验室,国家重点实验完成.①实验材料:赤芍总苷由西安奥晶科技发展有限公司提供,批号:060417,纯度>95%.人红白血病K562细胞株购自上海中科院细胞库.②实验方法:取对数生长期的K562细胞,培养24 h后加入50 mg/L赤芍总苷进行干预,光镜下观察细胞形态.MTT显色法检测25,50,75,100,150,200,400 mg/L赤芍总苷对K562细胞增殖的抑制作用,以仅加入无血清培养基培养的为对照.③实验评估:采用Annexin V/PI双标记法检测凋亡效应,罗丹明123(Rh123)染色流式检测线粒体膜电位和荧光染料Fluo-3AM流式检测K562细胞内游离Ca2 浓度.结果:①50 mg/L 赤芍总苷作用K562细胞24 h后,出现核固缩、核碎裂和凋亡小体等形态学改变.②与对照组相比,不同质量浓度赤芍总苷能明显抑制K562细胞的增殖(P < 0.01),并具有量效关系,呈时间和剂量依赖性.③细胞线粒体经Rh123染色呈现明亮绿,不同质量浓度赤芍总苷干预组荧光强度均较对照组明显减弱,膜电位水平较高.④赤芍总苷可引起细胞线粒体膜电位下降.不同质量浓度赤芍总苷组细胞内游离Ca2 浓度均升高, 线粒体膜电位下降,与对照组比较差异显著(P < 0.01).结论:赤芍总苷诱导K562细胞凋亡的可能机制是通过减低细胞内线粒体膜电位及提高游离Ca2 水平,从而导致细胞凋亡.     

Effect of membrane potential on dialysis of calcium in a continuous-flow system.

Electical potentials across the membrane in a modified AutoAnalyzer dialyzer (Technicon) have been determined under various conditions and related to the dialysis of 45Ca. The results suggest that anomalies in the diffusion of calcium from protein and nonprotein containing streams could be due to factors other than "Donnan equilibrium effects."     

Effect of converting enzyme inhibitors on prostaglandin synthesis by isolated glomeruli and aortic strips from rats

In addition to their effect on angiotensin and bradykinin metabolism, converting enzyme inhibitors (CEI) may also alter prostaglandin (PG) synthesis. We therefore examined two CEI, SQ 14,225 (captopril) and SQ 20,881, for their in vitro effect on PG synthesis by glomeruli and aortic strips from rats. Glomeruli incubated in test tubes produced predominantly PGE2 and PGF2 alpha. Both CEI selectively stimulated PGE2 synthesis with maximal effects at 25 microM. During superfusion of glomeruli with captopril (25 microM) synthesis of PGE2 increased 5- to 10-fold and that of 6-keto-PGF1 alpha doubled. No significant change in PGF2 alpha or thromboxane B2 occurred. This effect of CEI was independent of angiotensin or bradykinin. In contrast captopril had no effect on PG synthesis by aortic strips, which produced predominantly prostacyclin assayed as 6-keto-PGR1 alpha and little PGE2 and PGF2 alpha. These results demonstrate that CEI can directly stimulate PG synthesis in glomeruli. This additional mechanism of action of CEI may require reinterpretation of the role of angiotensin based on results obtained with CEI.     

Effect of sodium taurocholate on amiloride-inhibitable sodium uptake and on intracellular pH of isolated rat hepatocytes

Evidence is accumulating that bile salts affect cellular mechanisms for the transport of inorganic electrolytes. We investigated the effect of amiloride on 22Na+ uptake rates in the presence and absence of sodium taurocholate (NaTC) and the effect of NaTC on intracellular pH (pHi) in isolated rat hepatocytes. Initial 22Na+ uptake rates (nanomoles per milligram of protein per minute) were significantly suppressed by amiloride (0.6 mmol/L), although the effect was small. NaTC significantly increased 22Na+ uptake rates. The amiloride-sensitive portion of 22Na+ uptake was significantly increased in the presence of NaTC (0.36 +/- 0.07 SEM nmol/mg protein/min vs. 0.20 +/- 0.07 nmol/mg protein/min, P less than 0.02). The pHi was estimated by using the pH probes carbon 14-labeled 5,5'-dimethyloxazolidinedione and acridine orange. NaTC caused intracellular alkalinization. Amiloride caused intracellular acidification, and the reduction of pHi by amiloride was enhanced in the presence of NaTC, although this enhancement is difficult to interpret because of the large effects of amiloride on pHi relative to those of NaTC. Our results indicate that NaTC affects sodium uptake by isolated hepatocytes probably by stimulating the Na+-H+ antiport.     

Effect of ouabain on the concentration of free cytosolic Ca++ and on contractility in cultured rat cardiac myocytes

Effects of ouabain on [Ca++]i and on contractility was measured in quin2 and fura2 loaded cultured neonatal rat cardiac myocytes. Addition of ouabain (5 x 10(-8) to 5 x 10(-6) M) to cultured myocytes exposed to balanced buffered salt solution (BSS) caused a transient increase in [Ca++]i, followed by slow oscillations for about 10 min, and by an elevated steady state level of [Ca++]i thereafter. Concentrations of ouabain between 10(-7) and 5 x 10(-7) M caused an increase in the amplitude of systolic motion (ASM) whereas concentrations above 10(-6) caused a decrease in the ASM, an increase in the beating frequency and an upward shift of the base line, indicating impaired relaxation. When ouabain was added to cardiac myocytes exposed to Ca++-free BSS the increase in [Ca++]i was not observed, but only a transient decrease. To investigate the effect of [K+]o on the ouabain-induced changes in [Ca++]i, ouabain was added to cells exposed to BSS containing low K+ concentration (1 mM instead of 5 mM in balanced BSS). In this medium the increase in ASM by ouabain was similar to that in balanced BSS. Addition of ouabain caused a transient decrease in [Ca++]i. There was no initial increase in [Ca++]i and the steady state level of [Ca++]i was not elevated as compared with the same cells before the addition of ouabain. Similar results were observed in cells loaded with quin2 or with fura2. In view of these results the mechanism of action of ouabain on cardiac myocytes is discussed.     

Effect of theophylline on membrane potential and contractile force in hamster diaphragm muscle in vitro.

Theophylline enhances the force of diaphragmatic contraction and delays fatigue. The mechanism is not known, but recent evidence suggests it may act at the cell membrane. To test this hypothesis, we studied the effect of theophylline on resting membrane potential and tension in hamster diaphragm cells. Muscle strips were obtained from five adult hamsters and placed in Krebs solution, aerated with 95% O2, 5% CO2. Resting membrane potential was measured using 3-M KCl-filled glass microelectrodes; 15-22 fibers in each strip were sampled. Force frequency curves (twitch to 100 Hz) were obtained. The muscle bath was then changed to one containing 100 mg/liter (0.55) theophylline. Resting membrane potential was -76 +/- 3 mV (mean +/- S.D.) in Krebs solution and increased to -85 +/- 3 mV (P less than 0.01) with added theophylline. Tension increased from 5% (at 100 Hz) to 20% (at 10 Hz) with theophylline. Hyperpolarization indicates an increase in intracellular to extracellular potassium concentration. Net potassium outflow occurs with each contraction, causing the cell membrane to become depolarized with repeated contractions, ultimately leading to fatigue. The hyperpolarization of the skeletal muscle cell membrane observed with theophylline may play an important role in prolonging time to fatigue.     

The influence of HIV infection and antiretroviral therapy on the mitochondrial membrane potential of peripheral mononuclear cells

OBJECTIVES: Clinical disorders occurring in HIV-infected patients on antiretroviral therapy (ART) have been linked to mitochondrial dysfunction, for example, lactic acidosis and lipodystrophy. Mitochondrial membrane potential (delta psi m) is the most direct measure of the state of energization of the mitochondria. We analysed delta psi m, of peripheral blood mononuclear cells (PBMCs) in HIV-negative, healthy subjects (n=8), HIV-infected, treatment-naive patients (n=30), and HIV-infected patients on ART (n=58). The influence of ART was analysed in six patients who started their first regimen. METHODS: The delta psi m of PBMC was measured by flow cytometry using the dye JC-1. RESULTS: The delta psi m was significantly lower in HIV-infected patients than in HIV-negative controls. This difference was detected in both treated (P = 0.0001) and untreated patients (P = 0.001). The delta psi m of PBMCs was highly correlated with CD4+ T-cell count in therapy-naive patients (P = 0.002, r = 0.546) and in treated patients (P = 0.028, r = 0.288). The delta psi m increased significantly in therapy-naive patients after starting ART (P = 0.001). Patients with lipoatrophy had significantly lower delta psi m than patients without lipodystrophy or with lipohypertrophy (P = 0.023). CONCLUSIONS: In HIV-infected persons delta psi m is significantly reduced. Patients with lipoatrophy have significantly reduced delta psi m. This is the first study showing that the delta psi m of PBMCs is highly correlated with CD4+ T-cell count in HIV infection.     

SCD1过表达影响高脂诱导鼠BRL肝细胞膜电位变化研究

目的探讨硬脂酰辅酶A去饱和酶1（SCD1）过表达影响大鼠BRL肝细胞系凋亡作用的可能机制。方法通过台盼兰染色检测不同浓度棕榈酸（PA）诱导BRL肝细胞死亡率确定下游实验PA添加浓度。培养细胞分组为非加药组和加药组。非加药组包括一般培养组（CON）、一般培养加阴性病毒组（NC）及一般培养加过表达病毒组（SCD1-LV）;加药组包括一般培养加PA组（CON＋）、一般培养加阴性病毒和PA组（NC＋）及一般培养加过表达病毒和PA组（SCD1-LV＋）。实时荧光定量聚合酶链反应（PCR）检测SCD1 mRNA表达的变化,流式细胞术测细胞线粒体膜电位（MMP）的变化,用膜电位正常细胞百分比（JC-1＋%）表示MMP改变。结果与对照组相比,400μmol/L PA诱导72 h细胞死亡率明显上升（P〈0.01）。PA诱导引起CON＋及NC＋组SCD1表达下降,SCD1-LV＋组及SCD1-LV组SCD1表达明显上升;CON＋和NC＋组JC-1＋%较低,SCD1-LV＋组JC-1＋%与对照组相似。结论用SCD1慢病毒载体感染BRL肝细胞系,SCD1表达升高,增强细胞对饱和脂肪酸的去饱和作用,过表达SCD1能降低PA诱导的脂毒性,使紊乱的MMP得到恢复。