猪心脏移植缺血再灌注损伤中NO和NOS的表达

①目的　了解猪同种原位心脏移植术后早期一氧化氮 (NO)、一氧化氮合酶 (NOS)含量的变化 ,及其与早期缺血再灌注损伤的关系。②方法　建立猪同种原位心脏移植模型。供心在移植前低温保存 (Thomas液 ,4℃ ) 4h ,移植成功心脏复搏后 2h取材。应用组织化学方法测定心肌组织中NO、NOS的含量 ,应用核酸原位末端标记法 (TUNEL)测定心肌细胞凋亡指数 ,作为评价心肌缺血再灌注损伤的指标。以正常心肌及单纯缺血心肌组织作为对照。③结果　移植后心肌组织NO、NOS的含量较缺血组与正常组低 ,差异有显著意义 (F =2 7.2 2 9、16 .2 0 3,q =5 .716～ 6 .4 12 ,P <0 .0 1)。移植组心肌细胞凋亡指数与正常组及缺血组比较明显升高 ,差异有显著性(F =16 3.884 ,q =7.4 82、6 .975 ,P <0 .0 1)。心肌组织NO、NOS含量与心肌细胞凋亡指数呈负相关关系 (r =- 0 .886、- 0 .795 ,P <0 .0 1)。④结论　猪心脏移植后早期心肌缺血再灌注损伤所致的细胞死亡主要表现为心肌细胞凋亡 ;再灌注期间内源性NO、NOS的减少参与了心脏移植后早期缺血再灌注损伤的发生     

Inhibition of Expression of Hypoxia-inducible Factor-1α mRNA by Nitric Oxide in Hypoxic Pulmonary Hypertension Rats

Hypoxiaisadirectfactorcausinghypoxicpul monaryhypertension (HPH) .hypoxiainduciblefac tor 1α (HIF 1α)isfoundtobethemostcrucialfactorsofarwhichmediatesthecellularresponsetohypoxi a[1] .OurpreviousstudyrevealedthatoverexpressionofHIF 1andendothelin 1(ET 1…     

新生大鼠缺氧缺血性脑损伤后血清和脑组织NO、NOS变化的相关性

目的 研究缺氧缺血性脑损伤(HIBD)后血清和脑组织中NO、NOS的变化，探讨其是否存在相关性。方法 取空白对照组、假手术组、缺氧缺血后30min、2h、24h、72h大鼠血清、脑组织标本进行NO和NOS的检测。NO测定采用硝酸还原酶法，用分光光度计比色法测定NO和NOS。结果 (1)缺氧缺血组NO、NOS增高，与假手术组、空白对照组比较差异有显著性，但后两组差异无显著性。(2)新生大鼠脑缺氧缺血后NO、NOS随时间的延长而逐渐升高。(3)血清、脑组织NO、NOS的变化存在相关性。结论 新生大鼠缺氧缺血性脑损伤后血清和脑组织中NO、NOS都有不同程度的升高，而且存在相关性。可以通过血NO、NOS的检测了解脑组织的受损情况。     

Down-regulation of inducible nitric oxide synthase (iNOS) in rat with congenital hydronephrosis

BACKGROUND: Most of our knowledge concerning obstructive uropathy has been derived mainly from surgically manipulated animal models, and the pathogenesis of congenital obstructive hydronephrosis is not fully elucidated. Nitric oxide (NO) acts as an important biological modulator with diverse physiological functions, which can be either toxic or protective depending on the situation. NO is synthesized from l-arginine by nitric oxide synthase, and in the kidney iNOS is expressed spontaneously. The aim of our study is to investigate the expression of iNOS protein and its relationship with tubulointerstitial fibrosis and tubular cell apoptosis in congenital hydronephrosis. METHODS: We conducted histological studies on 18 kidneys of six-week-old-rats from an inbred colony of congenital hydronephrosis with reference to the histological grading of the affected kidney, tubulointerstitial fibrosis, renal tubular atrophy, and tubular cell apoptosis. Renal transforming growth factor-beta1 (TGF-beta1) level was determined by a sandwich ELISA assay and the expression of iNOS was analyzed by western blotting. RESULTS: Most of the hydronephrotic kidneys were markedly enlarged with dilatation of the collecting system, parenchymal thinning, tubular atrophy, interstitial infiltration and fibrosis. Renal TGF-beta1 level was higher in hydronephrotic kidneys than normal control kidneys (364.81 +/- 52.60 vs. 221.19 +/- 22.53 pg/mg protein, P < 0.05). Tubular apoptotic score in hydronephrotic kidneys was also significantly higher than in the normal control kidneys (1.97 +/- 0.42 vs. 0.14 +/- 0.02/HPF, P < 0.01). The expression of iNOS protein was lower in the affected kidneys compared with the normal control kidneys (8.79 +/- 0.78 vs. 14.00 +/- 0.83 arbitrary unit, P < 0.01). There was a negative correlation between iNOS expression and histological grading in congenital hydronephrosis. The iNOS expression also correlated negatively with renal interstitial fibrosis, TGF-beta1 level and tubular cell apoptosis. CONCLUSION: Our study confirmed the down-regulation of iNOS expression in affected kidneys from rats with congenital hydronephrosis, in which the cytoprotective effect of NO may be lost or weakened.     

缺血再灌注兔肺组织一氧化氮合酶的表达

目的 探讨兔肺缺血再灌注后一氧化氮合酶（NOS）同功酶表达变化的规律。方法 30只健康新西兰兔随机分成3组：正常组（Ⅰ组），假手术组（Ⅱ组），缺血再灌注组（Ⅲ组），每组10只。建立肺缺血再灌注模型，采用免疫组织化学方法检测再灌注肺组织内皮型（eNOS)和诱导型（iNOS)一氧化氮合酶表达的变化。结果 （1）Ⅰ，Ⅱ组肺组织未见iNOS的表达，eNOS在内皮细胞表达正常。（2）Ⅲ组肺泡上皮细胞，平滑肌细胞，内皮细胞等均可见大量iNOS表达，eNOS表达下调。结论 再灌注肺组织eNOS表达减弱，iNOS表达增强，与肺组织缺血再灌注损伤密切相关。     

妊娠肝内胆汁淤积症患者血清一氧化氮和内皮素的变化及意义

目的：探讨妊娠肝内胆汁淤积症（ICP）患者外周静脉血清、新生儿脐静脉血清中一氧化氮（NO）、内皮素（ET）、丙二醛（MDA）和超氧化物歧化酶（SOD）含量的变化及在ICP发病中的作用。方法：以ICP组28例为研究组，测定其外周静脉血清及新生儿脐静脉血清中的NO、ET、MDA和SOD，以年龄相近的24例正常孕妇作为对照组。结果：ICP患者的MDA和ET含量较正常晚期妊娠显著增高（P＜0．01），ICP患者的NO和SOD含量与对照组相比无显著性差异（P＞0．05）。母血清中NO、ET、MDA含量均较新生儿脐静脉血清中的含量高，差异有显著性（P＜0．01）。结论：妊娠期体内氧化和抗氧化失衡及ET水平的增高可能与ICP的发生、发展有关。     

Platelet nitric oxide synthase is activated by tyrosine dephosphorylation: possible role for SHP-1 phosphatase

BACKGROUND: Endothelial nitric oxide synthase (eNOS) activity in endothelial cells is regulated by post-translational phosphorylation of critical serine, threonine and tyrosine residues in response to a variety of stimuli. However, the post-translational regulation of eNOS in platelets is poorly defined. OBJECTIVES: We investigated the role of tyrosine phosphorylation in the regulation of platelet eNOS activity. METHODS: Tyrosine phosphorylation of eNOS and interaction with the tyrosine phosphatase SHP-1 were investigated by coimmunoprecipitation and immunoblotting. An in vitro immunoassay was used to determine eNOS activity together with the contribution of protein tyrosine phosphorylation. RESULTS: We found platelet eNOS was tyrosine phosphorylated under basal conditions. Thrombin induced a dose- and time-dependent increase in eNOS activity without altering overall level of tyrosine phosphorylation, although we did observe evidence of minor tyrosine dephosphorylation. In vitro tyrosine dephosphorylation of platelet eNOS using a recombinant protein tyrosine phosphatase enhanced thrombin-induced activity compared to thrombin alone, but had no effect on endothelial eNOS activity either at basal or after stimulation with bradykinin. Having shown that dephosphorylation could modulate platelet eNOS activity we examined the role of potential protein phosphatases important for platelet eNOS activity. We found SHP-1 protein tyrosine phosphatase, co-associated with platelet eNOS in resting platelets, but does not associate with eNOS in endothelial cells. Stimulation of platelets with thrombin increased SHP-1 association with eNOS, while inhibition of SHP-1 abolished the ability of thrombin to induce elevated eNOS activity. CONCLUSIONS: Our data suggest a novel role for tyrosine dephosphorylation in platelet eNOS activation, which may be mediated by SHP-1.     

诱导型一氧化氮合酶在前列腺增生组织中表达的研究

目的：探讨诱导型一氧化氮合酶(iNOS)与前列腺增生(BPH)病理生理变化的关系。方法:用免疫组化法检测10例正常和30例有膀胱出口梗阻的BPH患者膀胱和前列腺组织中iNOS的表达。结果：BPH组前列腺组织中iNOS呈阳性染色，主要分布于前列腺的上皮细胞及上皮下组织中，间质平滑肌组织中均为阴性；对照组的膀胱壁、膀胱颈部和前列腺组织中均无iNOS阳性染色。结论：iNOS仅在BPH患者前列腺组织中有特异性表达，提示它参与了前列腺增生的病理生理过程。     

Melatonin reduces nitric oxide synthase activity in rat hypothalamus

Abstract: In this report, rat hypothalamic nitric oxide synthase (NOS) activity is shown to be partially inhibited by physiological concentrations of the pineal hormone melatonin. In vitro studies demonstrate that 1 nM melatonin, which approximates the physiological concentration of the hormone at night, significantly inhibited NOS activity. In vivo studies show that administering melatonin or collecting the hypothalamus from animals at night, when endogenous melatonin levels are elevated, results in a significant decrease of NOS activity. Results also show that calmodulin may be involved in this process since its presence in the incubation medium prevents the inhibitory effect of melatonin on NOS activity.     

Functional role and histological demonstration of nitric-oxide-mediated inhibitory nerves in dog sphincter of Oddi

Abstract Nitric oxide (NO) plays an important physiological role in regulating gastrointestinal motility. Involvement of endogenous NO was evaluated in the response to non-adrenergic, non-cholinergic (NANC) nerve stimulation of the dog sphincter muscle of Oddi. Transmural electrical stimulation (TES), nicotine (10^?5M) and K⁺ (10 mM) produced only a relaxation in the sphincter muscle strips contracted with substance P, which was not potentiated by atropine. The TES-induced relaxation was abolished by tetrodotoxin (3 times 10^?7 M) and oxyhaemoglobin (1.6 times 10^?5 M), but not affected by atropine (10^?7 M), propranolol (10^?7 M), phentolamine (10^?7 M), indomethacin (10^?6 M), chole-cystokinin (CCK, 10^?8 M) and vasoactive intestinal polypeptide (VIP, 10^?8 M). The relaxation was also abolished by treatment with N^G-nitro-L-arginine (L-NA, 10^?5 M), an NO synthase inhibitor. Nicotine produced a transient relaxation, which was abolished by tetrodotoxin, hexamethonium (10^?5 M) and L-NA, but not affected by atropine and N^G-nitro-D-arginine (D-NA, 10^?5 M). The addition of K⁺ elicited a transient relaxation, which was abolished by tetrodotoxin and L-NA. The inhibitory effects of L-NA were antagonized by L-arginine (10^?3 M). The presence of neurons containing nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase was histochemically demonstrated in the sphincter of Oddi. These findings may indicate that TES, nicotine and K⁺ liberate NO from NANC inhibitory nerve which is involved in the relaxation of the dog sphincter of Oddi. The muscular tone does not seem to be regulated by cholinergic nerves under the experimental conditions used.