Ovary and Ovulation: Human follicular nitric oxide pathway: relationship to follicular size, oestradiol concentrations and ovarian blood flow

Nitric oxide (NO) has been suggested to be involved in ovarianphysiology. Our aim was to study follicular nitrite and nitrate(NO₃/NO₂) levels in women undergoing in-vitro fertilization(IVF), and to examine their relationship to follicular size,oestradiol concentrations, and ovarian artery and intra-ovarianblood flow as measured by Doppler ultrasound. A total of 15patients from the IVF programme of Hadassah University Hospital,Mt Scopus, Israel, participated in the study. Detailed transvaginalultrasonographic examination was performed before ovum collection,and ovarian artery and intra-ovarian blood flow were measured.While aspirating the fofficles, the content of two to four ofthe fofficles in each ovary was collected individually, thevolume of follicular fluid measured, and NO₃/NO₂ concentrationswere determined. A statistically significant positive correlationwas found between follicular fluid NO₃/NO₂ concentrations andfollicular volume (r = 0.76), as well as between NO₃/NO₂ concentrationsand oestradiol concentrations (r = 0.63). A statistically significantnegative correlation was found between follicular fluid NO₃/NO₂concentrations and ovarian flow parameters as well as betweenNO₃/NO₂ concentrations in fofficles containing 4–5 mland ovarian artery pulsatility index.     

Effects of endothelin receptor type A antagonism and nitric oxide synthase inhibition on cerebral blood flow in hypertensive rats

Effects of the endothelin receptor type A antagonist BQ 123 and the NO synthase inhibitor L -NMMA on cerebral blood flow were studied in vivo in anaesthetized hypertensive (SHR) and normotensive (WKY) rats. The effects of acetylcholine following pre-treatment with these drugs were also studied with the microsphere method for blood flow determination in the cortex, thalamus, caudatus, pons, medulla, cerebellum and hypophysis. BQ 123 (1 mg kg^?1) induced only minor effects on cerebral blood flow in both strains (n = 8), whereas L -NMMA (N = 8; 20 mg kg^?1) reduced regional cerebral blood flow significantly in most regions (21–54%) in the hypertensive, but not in the normotensive rat. In normotensive rats pre-treated with BQ 123 intravenous administration of acetylcholine (2 μg kg^?1 min^?1) induced a widespread significant increase (20–50%) in cerebral blood flow despite a reduction of the mean arterial blood pressure, while no significant effects were seen in hypertensive animals. Intravenous infusion of acetylcholine in animals pre-treated with L -NMMA did not affect cerebral blood flow in most regions in either of the two rat strains. In conclusion, a vasodilatory response to acetylcholine was found following endothelin receptor A antagonism in the WKY rat only, suggesting a role for endothelin in the control of cerebral blood flow in this strain. Furthermore, a higher basal vasodilating nitric oxide-tone seems to be present in the hypertensive rat compared with the normotensive rat.     

Nitric oxide modulates acetylcholine‐induced vasodilatation in the hepatic arterial vasculature of the dual‐perfused rat liver

The role of nitric oxide in the modulation of hepatic arterial vascular reactivity was investigated in an isolated dual‐perfused rat liver preparation. Twelve male Wistar rats (200–250 g) were anaesthetized with sodium pentobarbitone (60 mg kg^–1 i.p.). The livers were then excised and perfused in vitro through hepatic arterial and portal venous cannulae at constant flow rates. Concentration‐dependent dose–response curves to acetylcholine (10^–8–10^–5 M ), sodium nitroprusside (10^–6–5 × 10^–4 M ), and adenosine triphosphate (ATP) (10^–8–10^–5 M ) in the hepatic artery were constructed after the tone was raised by addition of methoxamine (3 μM L^–1). Acetylcholine‐induced vasodilatation in the hepatic artery was significantly attenuated with inhibition of nitric oxide synthase by using N^G‐nitro‐L ‐arginine methyl ester (30 μM ), E_max=51.7 ± 2.8 vs. 32.5 ± 3.1 mmHg, before vs. after N^G‐nitro‐L ‐arginine methyl ester, respectively. ATP‐induced hepatic arterial vasoconstriction which was significantly enhanced with L ‐NAME, E_max=94.0 ± 9.3 vs. 127.0 ± 8.0 mmHg, before vs. after N^G‐nitro‐L ‐arginine methyl ester, respectively. Sodium nitroprusside‐induced hepatic arterial vasodilatation remained unchanged with N^G‐nitro‐L ‐arginine methyl ester, E_max=57.0 ± 3.4 vs. 57.0 ± 4.1, before vs. after N^G‐nitro‐L ‐arginine methyl ester, respectively. The data from the present study suggest that acetylcholine‐induced vasodilatation in the intrahepatic arterial vasculature of the rat liver is at least, in part, mediated by the release of nitric oxide. In addition, ATP‐induced hepatic arterial vasoconstriction is also modulated by the release of nitric oxide (*P < 0.05, Student’s paired t‐test).     

缺氧时心肌血流量的变化及一氧化氮和内皮素-1的调节作用

目的探讨一氧化氮和内皮素-1在缺氧时对心肌血流量的调节作用。方法大鼠随机分为平原组和急性缺氧组,用99mTc标记蟾蜍红细胞测定心肌血流量,用Gess法和放免法分别测量血浆和心肌NO2-、内皮素-1（endothelin-1,ET-1）含量,用双波长分光光度法测量一氧化氮氧合酶（nitric oxide synthase,NOS）活性。结果急性缺氧导致左右心室心肌血流量、血浆和心肌血NO2-、ET-1含量、NOS活性明显增高（P〈0.05）,左右心室心肌血管阻力和心肌ET-1/NO2-比值明显下降（P〈0.05）,血球压积（Hct）及心室重量指数无明显变化。结论急性缺氧时,左右心室心肌血流量增加,ET-1/NO参与了急性缺氧时心肌血流量的调节,以NO的扩血管作用为主。     

Nitric oxide and the role of blood pressure variability to the kidney

Blood pressure variability is buffered by at least two mechanisms: the arterial baroreceptor reflex and nitric oxide (NO). Only recently is the importance of blood pressure variations on cardiovascular control being investigated. Here we report of a study performed in conscious dogs, in which renovascular hypertension was induced. Reduction of renal arterial pressure (RAP) to 85 mmHg for 24 h elicited profound hypertension by 60 mmHg (vs. control: 110 ± 3 mmHg; P < 0.01). This was accompanied by reduced volume and sodium excretion (–48% of control, P < 0.01 and –80% of control, P < 0.01, respectively) and augmented renin release by more than two‐fold (P < 0.01). This intervention was compared with a protocol in which RAP was reduced to the same mean value, however, RAP oscillated by ±10 mmHg at 0.1 Hz. This manoeuvre led to a transient increase in NO₃ excretion in urine (P < 0.01), blunted antidiuresis (–14% of control) as well as antinatriuresis (–40% of control) and attenuated the increased renin release by 30% (P < 0.05). In consequence, the magnitude of blood pressure increase was only half as high as that observed during static reduction of RAP (P < 0.01). It is concluded that blood pressure oscillations to the kidney have a profound influence on water and electrolyte balance and on renin release, which alleviates the onset of Goldblatt hypertension.     

Role of extracellular and intracellular nitric oxide in the regulation of macrophage responses

We studied the role of nitric oxide in the stress response and apoptosis. Intracellular nitric oxide potentiated the stress response. However, intracellular nitric oxide suppressed the stress response in macrophages of proinflammatory and antiinflammatory phenotypes. Intracellular nitric oxide promoted apoptosis in macrophages of the proinflammatory phenotype, but inhibited this process in cells of the antiinflammatory phenotype. Exogenous nitric oxide synthesized by macrophages protected them from lipopolysaccharide-induced apoptosis. Our results indicate that nitric oxide produces various effects on the stress response and apoptosis in macrophages, which depends on modus operandi. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 141, No. 4, pp. 386–388, April, 2006     

Effects of inhibition of neuronal nitric oxide synthase on NMDA-induced changes in cerebral blood flow and oxygen consumption

This study was performed to determine whether neuronal nitric oxide synthase (nNOS) is involved in altering regional cerebral blood flow (rCBF) and oxygen consumption during N-methyl-D-aspartate (NMDA) receptor stimulation. A craniotomy was performed in rats, under isoflurane anesthesia, to expose the cerebral cortex. For the control group (n=7), an NMDA patch (10^–3 M) was applied to the exposed cortex (ipsilateral cortex, IC) for 10 min before determining rCBF and O₂ consumption. The patch was changed every 5 min. To block nNOS, 7-nitroindazole (7-NI, 25 mg/kg i.p.) was administered 30 min before NMDA application (7-NI group, n=7). The autoradiographic technique was used to determine rCBF and regional O₂ consumption was measured using cryomicrospectrophotometry. Blood pressure, heart rate, blood gases, and hemoglobin were similar between the two groups. In the control group, rCBF (108±32 ml/100 g per min) and O₂ consumption (4.8±0.8 ml O₂/100 g per min) of the IC where NMDA was applied were higher than those of the contralateral cortex (CC) (78±16 ml/100 g per min and 3.1±0.4 ml O₂/100 g per min, respectively). Neither rCBF nor O₂ consumption of the IC of the 7-NI group was statistically different from that of the CC. However, O₂ consumption of the IC of the 7-NI group was lower (3.9±1.0 ml O₂/100 g per min) than that of the IC of the control group. Our data demonstrated that a direct cortical application of NMDA increased O₂ consumption and rCBF, and that pretreatment with 7-NI not only attenuated the effects of NMDA on rCBF but also decreased the O₂ consumption during NMDA receptor stimulation. Electronic Publication     

Oxygen or low concentrations of nitric oxide reverse pulmonary vasoconstriction induced by nitric oxide synthesis inhibition in rabbits

The objective of this study was to investigate the role of nitric oxide and oxygen in the regulation of pulmonary vascular resistance, especially by means of substitution with nitric oxide after inhibition of endogenous nitric oxide formation. In artificially ventilated open-chest rabbits pulmonary vascular resistance at normoxic ventilation (F₁0₂= 21%) was 56±6cmH₂O ml^-1 mim-¹ 1000^-1 (mRU_L). N^w-nitro-L-arginine methyl ester (l-NAME, 30 mg kg^-1), an inhibitor of NO synthase, increased pulmonary vascular resistance to 122±17 mRU_L at normoxic ventilation. In response to l-NAME there was also an increase in mean arterial blood pressure. Exogenous nitric oxide (0.014-9 p.p.m. in the inhaled air) dose-dependently and reversibly counteracted the effect of l-NAME on pulmonary vascular resistance at normoxic ventilation, without affecting systemic blood pressure. In addition, the L-NAME-induced vasoconstriction was critically dependent on oxygen. Thus, during hypoxic ventilation (F₁O₂= 10%) the pulmonary vascular resistance was increased approximately four-fold by the presence of L-NAME (30 mg kg^-1), and increments in F,0₂ (21–100%) dose-dependently and reversibly counteracted the effect of L-NAME on pulmonary vascular resistance. Taken together these findings demonstrate that inhalation of low doses of NO may act as a replacement when endogenous NO synthesis is inhibited, and that pulmonary vasoconstriction induced by NO synthesis inhibition is likely to be the result of interference with oxygen-dependent regulatory mechanisms. Endogenous NO cooperates with oxygen to evoke a vasodilator component of the pulmonary hypoxic pressor response, balancing a hitherto unknown constrictor mechanism.     

Nitric oxide regulates coronary blood flow at various coronary arterial pressures in intact porcine hearts

Nitric oxide (NO) is known to regulate basal coronary blood flow (CBF). The objective of the present study was to examine the importance of NO in CBF regulation at various coronary arterial pressures (CAPs) in vivo. Experiments were performed in 11 open-chest pentobarbitone sodium anaesthetized pigs. CAP was reduced in steps by a hydraulic occluder on the mid left anterior descending coronary artery (LAD) before and after a 5-min intracoronary infusion of the inhibitor of NO synthesis, A-nitro-L-arginine (NOARG, 30 /imo\ min“¹). CAP was recorded and NOARG infused through a catheter inserted into the LAD just distal to the occluder. CBF was measured by Doppler flowmetry on the LAD. NOARG significantly reduced CBF by 11±4, 20 ± 5, 10 ± 3, 15 ± 4, 19 ± 2, 25 ± 4 and 25 ± 5 mL min^-1 100 g^-1 (mean ± SE) at CAPs of 30 (n = 6), 40 (n = 9), 50 (n= 9), 60 (n = 9), 70 (n = 9), 80 (n = 8) and 90 (n = 6) mmHg, respectively. These decrements were not statistically different, but the percentage reductions in CBF after infusion of NOARG were significantly greatest at the lowest CAPs. The slight haemodynamic alterations induced by NOARG could not explain the reductions in CBF. Thus, the reductions in CBF after infusion of NOARG were caused by inhibition of a continuous NO release from the coronary endothelium. Coronary NO contributes significantly to CBF at all CAPs between 30 and 90 mmHg. The pronounced reduction in CBF during NO inhibition at the lower CAPs indicates an important vasodilating role of intact endothelium in a region supplied by a stenosed coronary artery.     

No effect of metabolic acidosis on nitric oxide production in hypoxic and hyperoxic lung regions in pigs

Aim: In the severely ill intensive care patients metabolic acidosis and hypoxia often co‐exist. We studied the effects of metabolic acidosis on nitric oxide synthase (NOS) dependent and NOS independent nitric oxide (NO) production in hypoxic and hyperoxic lung (HL) regions in a pig model. Methods: Eighteen healthy anaesthetized pigs were separately ventilated with hypoxic gas to the left lower lobe (LLL) and hyperoxic gas to the rest of the lung. Six pigs received HCl infusion (HCl group), six pigs received the non‐specific NOS inhibitor N^ω‐nitro‐l ‐arginine methyl ester (l ‐NAME) and HCl infusions (l ‐NAME + HCl group) and six pigs received buffered Ringer’s solution (control group). NO concentration in exhaled air (ENO), NOS activity in lung tissue, and regional pulmonary blood flow were measured. Results: Metabolic acidosis, induced by infusion of HCl, decreased the relative perfusion to the hypoxic LLL from 7 (3) [mean (SD)] to 3 (1) % in the HCl group (P < 0.01), and from 4 (1) to 1 (1) % in the l ‐NAME + HCl group (P < 0.05), without any measurable significant changes in ENO from hypoxic or HL regions There were no significant differences between the HCl and control groups for Ca²⁺‐dependent (cNOS) or Ca²⁺‐independent NOS (iNOS) activity in hypoxic or HL regions. Conclusions: Metabolic acidosis augmented the hypoxic pulmonary vasoconstriction, without any changes in pulmonary NOS dependent or NOS independent NO production. When acidosis was induced during ongoing NOS blockade, the perfusion of hypoxic lung regions was almost abolished, indicating acidosis‐induced pulmonary vasoconstriction was not NO dependent.     

血流切应力调控内皮型一氧化氮合酶的分子机制

血流切应力（flowshear stress，rss）是生理或病理条件下调节血管内皮细胞产生一氧化氮的最重要的刺激因素。FSS对内皮型一氧化氮合酶（endothelial nitric oxide synthase，eNOS）的调控包括基因转录的调节、转录后的调节和翻译后的调节。eNOS基因转录以及转录后mRNA的稳定性能被FSS诱导加强。FSS通过游离钙离子浓度、磷酸化、eNOS相关蛋白以及细胞内易位等途径调节eNOS的催化活性。此外，FSS还能调控eNOS催化反应的辅助因子。     

诱导型一氧化氮合酶与Dahl-盐敏感大鼠动脉血压的调节

目的和方法:为探讨诱导型一氧化氮合酶 (iNOS)在血液动力学调控中的作用,本研究通过慢性血液动力学实验观察了静脉输入诱导型一氧化氮合酶 (iNOS)抑制剂aminogunidine(AG)对大鼠平均动脉压的影响,并测定了一氧化氮 (NO)终产物NO₂及NO₃含量(UNOx)以及iNOS活性。结果:1.iNOS特异抑制剂AG能明显放大高钠引起的Dahl盐敏感大鼠(DS)的血压上升效应;2.高NaCl输入在导致的DS大鼠血压升高的同时,能引起iNOS活性及UNOx的明显升高。结论:iNOS对DS大鼠具有重要的血液动力学调节作用。     

Effects of long‐term inhibition of neuronal nitric oxide synthase on blood pressure and renin release

Nitric oxide (NO) produced by neuronal NO‐synthase (nNOS) in macula densa cells may be involved in the control of renin release. 7‐Nitro indazole (7‐NI) inhibits nNOS, and we investigated the effect of short‐ (4 days) and long‐term (4 weeks) 7‐NI treatment on blood pressure (BP), plasma renin concentration (PRC) and glomerular filtration rate (GFR) in rats on different salt diets. Rats were divided into three groups and given low‐salt (LS), normal (C) and high‐salt (HS) diets. Each diet group was subdivided into two groups treated either with 7‐NI or vehicle. Long‐term 7‐NI‐treated rats (LS and C) showed increased BP compared with controls (LS: 149 ± 4 vs. 133 ± 3; C: 146 ± 4 vs. 127 ± 4 mmHg). Blood pressure in HS rats did not differ from that in controls. Plasma renin concentration was stimulated in LS‐rats (251 ± 64 mGU mL^–1) compared with C and HS rats (42 ± 8 and 39 ± 5 mGU mL^–1, respectively) but was not significantly affected by chronic 7‐NI treatment (350 ± 103, 49 ± 10 and 50 ± 15 mGU mL^–1 in LS, C and HS, respectively). In rats treated with 7‐NI for 4 days, no effect on BP was seen, but PRC was increased in 7‐NI treated LS rats compared with vehicle treated LS rats (107 ± 15 vs. 56 ± 1 mGU mL^–1). Stimulation of PRC in LS rats was further enhanced by 7‐NI after 4 days of treatment, but not affected in rats treated for 4 weeks. This suggests that inhibition of nNOS stimulates renin release but that this stimulatory effect in the long run might be depressed by the increase in blood pressure.     

己烯雌酚对幼年香猪睾丸与附睾雌激素受体和一氧化氮合酶表达和分布的影响

目的 探讨己烯雌酚（DES）对幼年香猪睾丸和附睾中雌激素受体（ERs）和内皮型一氧化氮合酶（eNOS）表达的影响,及DES对诱导雄性动物生精异常的作用机制。 方法 将20只20～25日龄幼年雄性香猪分成４组,对照组只注射生理盐水,实验组经腹腔每天注射DES(实验1组：0.03mg/kg;实验2组：0.3mg/kg;实验3组：3mg/kg),连续注射9d。最后１次注射24h后手术取出左侧睾丸和附睾组织经中性多聚甲醛固定,石蜡包埋,常规制备5μm石蜡切片,采用免疫组织化学SP法检测睾丸和附睾组织中ERα、ERβ和eNOS的表达。 结果 ERα只在输出小管上皮细胞胞核中表达;ERβ在输出小管上皮细胞、间质细胞及附睾管上皮细胞胞核中均有表达,在睾丸生精小管细胞胞质中也有少量表达。DES能够使ERα在输出小管中的表达率显著下降（P<0.05）。随着DES用量的增多,ERβ在输出小管和附睾管中的表达率显著升高（P<0.05）,当DES用量为3mg/kg时ERβ在输出小管和附睾管中的表达率明显高于用量0.03mg/kg和0.3mg/kg（P<0.05）。但0.03mg/kg用量的DES却使睾丸生精小管中ERβ的表达率显著性下降（P<0.05）,并在0.3mg/kg和3mg/kg用量时在睾丸生精小管中未能检测到ERβ受体的表达。eNOS在睾丸生精小管细胞和输出小管上皮细胞中都有表达,DES能促进eNOS在睾丸生精小管细胞中表达（P<0.05）而降低其在输出小管细胞中表达（P<0.05）。结论 DES明显影响ERs和eNOS在睾丸和附睾中的表达。     

Role of nitric oxide in local blood flow control in the anaesthetized dog

Intravenous infusion of N ^G-nitro-L-arginine methyl ester (L-NAME), a potent inhibitor of nitric oxide (NO) formation from L-arginine, provokes marked rises in arterial blood pressure by increasing peripheral resistance. In order to further evaluate the contribution of basal NO-formation to control of organ blood flow, regional blood flow distribution within the myocardium, kidney and brain areas was assessed using the tracermicrosphere technique in anaesthetized dogs. After L-NAME (20 mg kg^–1 i.v.) kidney perfusion was homogeneously reduced by 55% in the entire cortex and the outer medulla. Within the left ventricular myocardium regional blood flow significantly decreased only in sub epicardial layers (–12%), whereas within the entire right ventricle regional blood flow was reduced by 19–24%. A close inverse relationship was found between all changes in regional myocardial blood flows observed after L-NAME and the respective control values. No significant changes in regional blood flow in different areas of the brain were detectable after L-NAME. It is concluded that the contribution of basal NO formation varies greatly between different organs and exhibits significant regional differences within the heart. It is possible that local metabolic mechanisms may compensate functionally for the inhibition of NO synthesis.     

Role of calcium-dependent K+ channels in the regulation of arterial and venous tone by nitric oxide in pigs

Effects of inhibition of calcium-dependent potassium channels (K⁺ _Ca channels) on the regulation of arterial and venous tone by nitric oxide (NO) were studied in anaesthetized pigs following vagotomy and blockade of autonomic ganglia. Selective inhibition of K⁺ _Ca channels by charybdotoxin (CTX, 2 μg/kg iv) or iberiotoxin (IbTX, 1 μg/kg) significantly augmented mean total peripheral resistance (TPR) to levels 30–60% above control. Venous and pulmonary vascular tone were assessed by changes in effective compliances of the venous (EVC) and pulmonary (EPC) vascular beds as calculated from changes in central venous and diastolic pulmonary arterial blood pressure during haemorrhagia (−5 ml/kg) and hypervolaemia (+5 ml/kg). Blockade of K⁺ _Ca channels significantly decreased both EVC (−20 to −30%) and EPC (−30 to −50%). Both CTX and IbTX significantly diminished the vasodilation caused by the NO-donor S-nitroso-N-acetylpenicillamine (SNAP) both during control conditions and following experimental vasoconstriction induced by systemic inhibition of NO-synthesis by NG-nitro-L-arginine methyl ester (L-NAME) or infusion of vasoconstrictor agonists. Dilator effects of the adenosine 3′,5′-cyclic monophosphate (cAMP)-dependent agonist adenosine were only slightly reduced. However, blockade of K⁺ _Ca channels did not increase vasoconstriction induced by L-NAME significantly. These results suggest that activation of vascular K⁺ _Ca channels is an important mechanism by which NO attenuates the constrictor tone of resistance and capacitance vessels in vivo. + _Ca channel blockade during vasoconstriction by agonists The effects of CTX on the haemodynamic responses to infusions of AII, AVP, NA and ET-1, at doses producing similar increases in MAP of about 50 mmHg, are listed in Table 1. The increase in TPR caused by NA and ET-1 was significantly smaller after CTX, whereas the responses to AII and AVP were similar both before and after CTX. To characterize this effect of K⁺ _Ca channel blockade further, we constructed dose-response curves for AII and NA with and without pretreatment with IbTX. The results for TPR are shown in Fig. 5. The constrictor responses to the two lower doses of NA were significantly reduced by IbTX. Received: 12 February 1996 / Accepted: 31 March 1996     

Glucocorticoid and ACTH regulation of rat peritoneal phagocyte chemiluminescence and nitric oxide production in culture

In order to study the adrenocortical regulation of monocyte/macrophage functions further, leucocytes from the rat peritoneum were incubated in vitro with glucocorticoid concentrations up to 10 μmol L^?1 and with adrenocorticotropic hormone (ACTH) up to 100 μg mL^?1. The monocyte/macrophage production of reactive oxygen molecules was measured by luminol amplified chemiluminescence, and the production of nitric oxide (NO) was measured as nitrite (NO₂^?). Dexamethasone in vitro in nanomolar concentrations inhibited monocyte/macrophage chemiluminescence and also nitric oxide production; the potency was dexamethasone > methylprodnisolone > prednisolone. ACTH enhanced both activated chemiluminescence and endotoxin-induced nitric oxide production, but only at concentrations about 20–100 μg mL^?1, and there was no significant effect of physiological concentrations. In summary, the results of the present study further confirm and substantiate that glucocorticoids in low pharmacological concentrations have a general inhibitory effect on monocyte/macrophage production of reactive oxygen molecules through the specific glucocorticoid receptors, while the stimulatory effect of ACTH is only observed by very high, non-physiological concentrations. Furthermore, since low concentrations of glucocorticoids inhibited the production of these reactive oxygen molecules in vitro, indirect mechanisms involving hormones and other elements outside the immune system are not essential for the effect of glucocorticoids on monocytes/macrophages.     

低糖诱导人脐静脉内皮细胞一氧化氮与活性氧变化的研究

目的观察低浓度葡萄糖对人脐静脉内皮细胞一氧化氮（NO）与活性氧（ROS）变化的影响。方法以体外培养人脐静脉内皮细胞株HUVEC-12为研究对象,将实验分为正常对照组（5.5mmol/L葡萄糖）、低糖组（2.8mmol/L葡萄糖）、无糖组（0mmol/L葡萄糖）。分别用2.8、0mmol/L葡萄糖干预HUVEC-12细胞,经过1、2、4、12h后,硝酸还原酶法测定NO产量,化学比色法测定一氧化氮合成酶（NOS）活性,Dihydroethidium荧光探针法测定细胞内ROS水平。结果与正常对照组相比,低糖组与无糖组NO水平降低（P〈0.01）,NOS活性下降（P〈0.01）,细胞内ROS水平升高（P〈0.01）,均呈剂量依赖关系。同一浓度组内随着时间的延长,内皮细胞NO水平、NOS活性进一步降低（P〈0.01）,ROS水平进一步升高（P〈0.05）,各指标都具有浓度和时间依赖性。结论低糖可导致内皮细胞功能障碍,NO水平降低,NOS活性下降,其机制可能与低糖导致内皮细胞氧化应激损伤有关。