Neurochemical coding in the myenteric plexus of the upper gastrointestinal tract of hibernating hamsters

As part of our investigation of the plasticity of autonomic nerves in physiological and pathological conditions, we have examined the effect of hibernation on the neurochemical content of myenteric nerves and nerve cell bodies of the upper gastrointestinal tract of the non-seasonal hibernator, the golden hamster. Age matched hamsters kept at room temperature and those kept at 5°C but failed to hibernate, were used as controls. Possible changes in nerve fibers and nerve cell bodies containing the general neuronal marker, protein gene product 9.5, the peptides, vasoactive intestinal polypeptide, substance P (SP) and calcitonin gene-related peptide (CGRP), the catecholamine synthesizing enzyme tyrosine hydroxylase and the enzyme responsible for synthesizing nitric oxide, nitric oxide synthase, were examined in the oesophagus, proventriculus and proximal and distal stomach of the golden hamsters using immunohistochemical techniques. The results of the present study revealed a significant increase in the number of nerve cell bodies and density of nerve fibers containing SP-immunoreactivity and increased number of CGRP-immunoreactive cell bodies but not the other markers examined in the proximal stomach and proventriculus. In contrast, there was no change in the distribution of any of the neuroactive substances examined in the myenteric plexus of the oesophagus and distal stomach. It is suggested that the change in the environment of the hibernating hamsters perturbs the normal digestive physiology in the proximal stomach and proventriculus that is reflected by the selective changes in SP- and CGRP-containing enteric nerves; these changes may be part of protective reflex mechanisms to the environmental changes resulting from hibernation, where upgrading of nerve cell bodies expessing CGRP and SP has occurred.     

The effect of nitric oxide donors on nitric oxide synthase-expressing myenteric neurones in culture.

Previously, we demonstrated that intestinal inflammation leads to a postinflammatory loss of nitric oxide synthase (NOS)-expressing myenteric neurones and motility disturbances. Here, we investigated whether high NO concentrations could be responsible for the decrease in NOS neurones. Myenteric neurone cultures, prepared from guinea-pig small intestine, were incubated with NO donors [sodium nitroprusside (SNP) and 3-morpholinosydnonimine (SIN-1)]. After fixation, NOS neurones were identified by NADPH diaphorase staining and neurone-specific enolase (NSE)-positive neuronal content was assessed with an enzyme-linked immunosorbent assay (ELISA)-based method. Twenty-four hours incubation with SIN-1 (10(-3) mol L(-1)) or SNP (10(-4) mol L(-1) or higher) reduced the number of NADPH diaphorase-positive neurones. SNP incubation did not affect the NSE-positive neuronal content. Shorter incubations (SNP: 4 and 12 h) had no significant effect. The SNP-induced reduction was reversed by glutathione (GSH), but not by NO- or O-scavengers, whereas GSH depletion enhanced the decrease. The NO-dependent guanylate cyclase-blocker 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) did not affect the SNP effect. This reduction can be explained by either specific apoptosis of NOS neurones or downregulation of NOS activity. However, TdT-mediated X-dUTP nick end labelling (TUNEL stainings argue in favour of the latter. In conclusion, the NO donor SNP decreases the number of NOS-expressing myenteric neurones time and concentration dependently, without affecting the amount of neuronal material. Glutathione plays an important protective role.     

Role of neuronal and inducible nitric oxide synthases in the guinea pig ileum myenteric plexus during in vitro ischemia and reperfusion

Background Intestinal ischemia and reperfusion (I/R) injury leads to abnormalities in motility, namely delay of transit, caused by damage to myenteric neurons. Alterations of the nitrergic transmission may occur in these conditions. This study investigated whether an in vitro I/R injury may affect nitric oxide (NO) production from the myenteric plexus of the guinea pig ileum and which NO synthase (NOS) isoform is involved. Methods The distribution of the neuronal (n) and inducible (i) NOS was determined by immunohistochemistry during 60 min of glucose/oxygen deprivation (in vitro ischemia) followed by 60 min of reperfusion. The protein and mRNA levels of nNOS and iNOS were investigated by Western‐immunoblotting and real time RT‐PCR, respectively. NO levels were quantified as nitrite/nitrate. Key Results After in vitro I/R the proportion of nNOS‐expressing neurons and protein levels remained unchanged. nNOS mRNA levels increased 60 min after inducing ischemia and in the following 5 min of reperfusion. iNOS‐immunoreactive neurons, protein and mRNA levels were up‐regulated during the whole I/R period. A significant increase of nitrite/nitrate levels was observed in the first 5 min after inducing I/R and was significantly reduced by N^ω‐propyl‐l ‐arginine and 1400 W, selective inhibitors of nNOS and iNOS, respectively. Conclusions & Inferences Our data demonstrate that both iNOS and nNOS represent sources for NO overproduction in ileal myenteric plexus during I/R, although iNOS undergoes more consistent changes suggesting a more relevant role for this isoform in the alterations occurring in myenteric neurons following I/R.     

Inhibitors of advanced glycation end-products prevent loss of enteric neuronal nitric oxide synthase in diabetic rats.

Gastrointestinal dysfunction is common in diabetes, and several studies indicate that loss of neuronal nitrergic inhibition may play an important role in its pathogenesis. However, the mechanisms responsible for this effect remain largely unknown. We have previously shown that advanced glycation end-products (AGEs) formed by non-enzymatic glycation dependent processes, can inhibit the expression of intestinal neuronal nitric oxide synthase (nNOS) in vitro acting via their receptor, receptor for AGEs. We now hypothesized that this effect may also be important in experimental diabetes in vivo. We aimed to evaluate the role of AGEs on duodenal nNOS expression and the effects of aminoguanidine (a drug that prevents AGE formation) and ALT-711 (AGE cross-link breaker) in experimental diabetes. Streptozotocin induced diabetic rats were randomized to no treatment, treatment with aminoguanidine (1 g L(-1) daily through drinking water) at the induction of diabetes, or treatment with ALT-711 (3 mg kg(-1) intraperitoneally), beginning at week 6. A fourth group was used as healthy controls. We performed real time polymerase chain reaction, Western blotting and immunohistochemistry to detect nNOS expression. AGE levels were analysed using sandwich ELISA. Diabetes enhanced accumulation of AGEs in serum, an effect that was prevented by treatment with aminoguanidine and ALT-711. Further, diabetic rats showed a significant reduction in duodenal nNOS expression by mRNA, protein and immunocytochemistry, an effect that was prevented by aminoguanidine. ALT-711 had similar effects on nNOS protein and immunohistochemistry (but not on mRNA levels). The generation of AGEs in diabetes results in loss of intestinal nNOS expression and may be responsible for enteric dysfunction in this condition. This study suggests that treatment directed against AGEs may be useful for the treatment of gastrointestinal complications of diabetes.     

Vasoactive intestinal peptide and nitric oxide promote survival of adult rat myenteric neurons in culture

Several motility disorders originate in the enteric nervous system (ENS). Our knowledge of factors governing survival of the ENS is poor. Changes in the expression of vasoactive intestinal peptide (VIP) and nitric oxide synthase (NOS) in enteric neurons occur after neuronal injury and in intestinal adaptation. The aim of this study was to evaluate whether VIP and nitric oxide (NO) influence survival of cultured, dissociated myenteric neurons. Neuronal survival was evaluated after 0, 4, and 8 days in culture. Influence of VIP and NO on neuronal survival was examined after culturing in the presence of VIP, NO donor, VIP antiserum, or NOS inhibitor. A marked loss of neurons was noted during culturing. VIP and NO significantly promoted neuronal survival. Corroborating this was the finding of an enhanced neuronal cell loss when cultures were grown in the presence of VIP antiserum or NOS inhibitor.     

Peripheral neuropathy in the spontaneously diabetic BB-Wistar-rat

Summary Peripheral nerves of the diabetic insulin-dependent BB-Wistar-rat were studied ultrastructurally. Conspicuous early changes consisted of mitochondrial accumulation of glycogen in the axons and the development of honey-combed Schwann cell-axon networks. The later stages of the diabetic syndrome showed axonal dwindling and disintegration in both myelinated and unmyelinated fibers. The present findings are compared with those of other experimental diabetic models.Supported in part by grants from the Canadian Diabetic Association. The Juvenile Diabetic Foundation (79B377), and the Medical Research Council of Canada (MA-7117)     

Inhibition of nitric oxide synthase aggravates brain injury in diabetic rats with traumatic brain injury

Studies have shown that hyperglycemia aggravates brain damage by affecting vascular endothelial function. However, the precise mechanism remains unclear. Male Sprague-Dawley rat models of diabetes were established by a high-fat diet combined with an intraperitoneal injection of streptozotocin. Rat models of traumatic brain injury were established using the fluid percussion method. Compared with traumatic brain injury rats without diabetic, diabetic rats with traumatic brain injury exhibited more severe brain injury, manifested as increased brain water content and blood-brain barrier permeability, the upregulation of heme oxygenase-1, myeloperoxidase, and Bax, the downregulation of occludin, zona-occludens 1, and Bcl-2 in the penumbra, and reduced modified neurological severity scores. The intraperitoneal injection of a nitric oxide synthase inhibitor N(5)-(1-iminoethyl)-L-ornithine(10 mg/kg) 15 minutes before brain injury aggravated the injury. These findings suggested that nitric oxide synthase plays an important role in the maintenance of cerebral microcirculation, including anti-inflammatory, anti-oxidative stress, and anti-apoptotic activities in diabetic rats with traumatic brain injury. The experimental protocols were approved by the Institutional Animal Care Committee of Harbin Medical University, China(approval No. ky2017-126) on March 6, 2017.     

Afferent nerve sensitivity is decreased by an iNOS-dependent mechanism during indomethacin-induced inflammation in the murine jejunum in vitro

Abstract Evidence exists that visceral afferent sensitivity is subject to regulatory mechanisms. We hypothesized that afferent sensitivity is decreased in the small intestine during intestinal inflammation by an inducible nitric oxide synthase (iNOS)‐dependent mechanism. C57BL/6 mice were injected twice with vehicle or 60 mg kg^?1 indomethacin subcutaneously to induce intestinal inflammation. Afferent sensitivity was recorded on day 3 from a 2‐cm segment of jejunum in vitro by extracellular multi‐unit afferent recordings from the mesenteric nerve bundle. In subgroups (n = 6), iNOS was inhibited selectively by L‐N6‐(1‐iminoethyl)‐lysine (L‐NIL) given either chronically from day 1–3 (3 mg kg^?1 twice daily i.p.) or acutely into the organ bath (30 μmol L^?1). The indomethacin‐induced increase of macroscopic and microscopic scores of intestinal inflammation (both P < 0.05) were unchanged after pretreatment with L‐NIL. Peak afferent firing following bradykinin (0.5 μmol L^?1) was 55 ± 8 impulse s^?1 during inflammation vs 97 ± 7 impulse s^?1 in controls (P < 0.05). Normal firing rate was preserved following L‐NIL pretreatment (112 ± 16 impulse s^?1) or acute administration of L‐NIL (108 ± 14 impulse s^?1). A similar L‐NIL dependent reduction was observed for 5‐HT (250 μmol L^?1) and mechanical ramp distension from 20 to 60 cmH₂O (both P < 0.05). Intraluminal pressure peaks were decreased to 0.66 ± 0.1 cmH₂O during inflammation compared to 2.51 ± 0.3 in controls (P < 0.01). Afferent sensitivity is decreased by an iNOS‐dependent mechanism during intestinal inflammation which appears to be independent of the inflammatory response. This suggests that iNOS‐dependent nitric oxide production alters afferent sensitivity during inflammation by interfering with signal transduction to afferent nerves rather than by attenuating intestinal inflammation.     

Sepiapterin reverses the changes in gastric nNOS dimerization and function in diabetic gastroparesis

Background We have demonstrated previously that in vivo supplementation of tetrahydrobiopterin (BH₄); a co‐factor for neuronal nitric oxide synthase (nNOS) significantly restored delayed gastric emptying and attenuated nitrergic relaxation in diabetic rat. In this study, we have investigated whether supplementation of sepiapterin (SEP), a precursor for BH₄ biosynthesis via salvage pathway restores gastric emptying and nitrergic system in female diabetic rats. Methods Diabetic rats (streptozotocin‐induced) were supplemented with BH₄ or SEP (20 mg kg^?1 body weight). Gastric nitrergic relaxation in the presence or absence of high glucose and SEP were measured by electric field stimulation. Gastric muscular strips from healthy or diabetic female rats were incubated in the presence or absence of high glucose, SEP and/or methotrexate (MTX). Nitric oxide release was measured colorimetrically by NO assay kit. The expression of nNOSα and dimerization was detected by Western blot. Key Results In vitro studies on gastric muscular tissues showed that MTX, an inhibitor of BH₄ synthesis via salvage pathway, significantly decreased NO release. In vivo treatment with MTX reduced both gastric nitrergic relaxation and nNOSα dimerization. Supplementation of SEP significantly attenuated delayed gastric emptying in diabetic rats. In addition, SEP supplementation restored impaired nitrergic relaxation, gastric nNOSα protein expression, and dimerization in diabetic rats. Conclusions & Inferences The above data suggests that supplementation of SEP accelerated gastric emptying and attenuated reduced gastric nNOSα expression, and dimerization. Therefore, SEP supplementation is a potential therapeutic option for female patients of diabetic gastroparesis.     

冰片促血脑屏障开放与一氧化氮含量改变的关系初探

目的 :探讨内皮细胞型一氧化氮合成酶 (e NOS)与冰片促血脑屏障 (BBB)开放作用的关系。方法 :采用链菌素亲生物素 -过氧化氢酶法 (S- P法 )染色和抗 e NOS抗体的免疫组化方法 ,观察正常与脑外伤情况下服用冰片后大鼠脑微血管内皮细胞 (EC)中 e NOS表达量的变化。结果 :脑外伤时 ,因 EC受损 ,e NOS表达减弱 ,冰片可增加生理、病理状态下大鼠脑微血管内皮细胞中 e NOS的表达量。结论 :NO与冰片促 BBB开放作用有一定联系     

NOS在棕色田鼠胃肠道各段肌间神经丛分布的比较

目的：解释棕色田鼠(Microtus mandarinus)消化道对其生活史特征的适应性调节机制。方法：用NAD-PH-黄递酶组织化学法对NOS在棕色田鼠胃肠肌间神经丛的分布进行比较研究。结果：棕色田鼠胃肠肌间神经丛NOS阳性神经元形态各异，大小悬殊数倍；神经节和阳性神经纤维构成网络结构，阳性神经元可呈“串珠”状和“U”形排列。NOS阳性神经元分布密度在胃肠道各段差异较大：结肠密度最高，回肠次之，胃和盲肠比回肠低，比十二指肠和空肠高。结论：棕色田鼠NOS阳性神经元在胃肠道各节段肌间神经丛的分布特点可能是与其食性和生理机能相适应的。     

NOS在棕色田鼠胃肠道各段肌间神经丛分布的比较

目的:解释棕色田鼠(Microtus mandarinus)消化道对其生活史特征的适应性调节机制.方法:用NAD-PH-黄递酶组织化学法对NOS在棕色田鼠胃肠肌间神经丛的分布进行比较研究.结果:棕色田鼠胃肠肌间神经丛NOS阳性神经元形态各异,大小悬殊数倍;神经节和阳性神经纤维构成网络结构,阳性神经元可呈"串珠"状和"U"形排列.NOS阳性神经元分布密度在胃肠道各段差异较大:结肠密度最高,回肠次之,胃和盲肠比回肠低.比十二指肠和空肠高.结论:棕色田鼠NOS阳性神经元在胃肠道各节段肌间神经丛的分布特点可能是与其食性和生理机能相适应的.     

Regional variation in the neurochemical coding of the myenteric plexus of the human colon and changes in patients with slow transit constipation

Abstract There are differences in the structure and function between regions of the colon. In patients with slow transit constipation the activity of all regions is markedly slowed. Counts of colonic neurones in slow transit constipation have been semiquantitative and led to varying results. We have applied new methods of quantification of markers in whole mounts of the colonic myenteric plexus to compare density of innervation between regions and between normal patients and those undergoing resection for severe constipation. Whole mounts of colonic myenteric plexus were made from specimens removed for cancer treatment (controls) and cases of severe constipation. All neurones were labelled by anti‐human neuronal protein antibodies. Neurones synthesizing acetyl choline were labelled for choline acetyltransferase (ChAT) and those for nitric oxide by antisera to nitric oxide synthase (NOS). Four populations of neurones were distinguished and quantified according to the two selective markers, ChAT and NOS. In the normal major populations were NOS alone (51% of ascending colon neurones and 44% of descending colon neurones) and ChAT alone (41% ascending colon, 48% descending colon). Nitric oxide synthase/ChAT and NOS‐/ChAT‐comprised only small populations. In all regions in severe constipation, the percentage of NOS‐only colonic myenteric neurones was raised (54% ascending colon, 49% descending colon) and ChAT only was reduced (36% ascending colon, 42% descending colon). The other populations were not changed. Accurate quantification of neuronal populations in whole mounts of human colon reveals inter‐regional differences in innervation and marked changes in innervation in cases of very severe constipation.     

帕金森病大鼠胃肠功能障碍和肌间神经丛一氧化氮变化的研究

目的探讨6-羟基多巴胺(6-hydroxydopamine,6-OHDA)诱导的SD大鼠帕金森病(PD)模型胃肠功能障碍及肌间神经丛一氧化氮的变化。方法 60只SD大鼠随机分为对照组和6-OHDA组,每组30只,以6-OHDA诱导制备PD大鼠模型。4w后收集大鼠1h粪便排出量;计算粪便含水量;测定餐后2h大鼠胃内固体食物残留率。采用免疫组化法检测胃肠神经丛神经元型一氧化氮合酶(nNOS)表达变化;反转录聚合酶链式反应技术(RT-PCR)检测胃、结肠组织nNOS mRNA水平的变化。结果与对照组相比,6-OHDA组1h粪便湿重、干重、及含水量明显降低,胃内固体食物残留率明显增加(均P<0.01);胃窦和结肠肌间神经丛nNOS阳性区平均积分光密度明显降低(P<0.01);胃窦、结肠组织nNOS mRNA水平明显降低(P<0.01)。结论 PD大鼠胃肠功能障碍可能与胃肠神经系统nNOS水平降低有关。     

Role of nitric oxide in the brain during lipopolysaccharide-evoked systemic inflammation

Although the inducible isoform of nitric oxide synthase (iNOS) is a well-established source of nitric oxide (NO*) during inflammation of the central nervous system (CNS), little is known about the involvement of constitutive isoforms of NOS (cNOS) in the inflammatory process. The aim of this study was to compare the responses of the expression and activity of iNOS and the two cNOS isoforms, neuronal and endothelial (nNOS and eNOS, respectively), in the brain to systemic inflammation and their roles in the cascade of events leading to degeneration and apoptosis. A systemic inflammatory response in C57BL/6 mice was induced by intraperitoneal injection of lipopolysaccharide [LPS; 1 mg/kg body weight (b.w.)]. The relative roles of the NOS isoforms were evaluated after injection of NG-nitro-L-arginine (NNLA; 30 mg/kg b.w.), which preferentially inhibits cNOS, or 1400W (5 mg/kg b.w.), an inhibitor of iNOS. Biochemical and morphological alterations were analyzed up to 48 hr after administration of LPS. Systemic LPS administration evoked significant ultrastructural alterations in brain capillary vessels, neuropils, and intracellular organelles of neurons, astrocytes, and microglia. Apoptotic/autophagic processes occurred in many neurons of the substantia nigra (SN), which coincided with exclusive enhancement of iNOS expression and activity in this brain region. Moreover, inhibitors of both iNOS and cNOS prevented LPS-evoked release of apoptosis-inducing factor (AIF) from SN mitochondria. Collectively, the results indicate that synthesis of NO* by both the inducible and constitutive NOS isoforms contribute to the activation of apoptotic pathways in the brain during systemic inflammation.     

癫痫患儿血清一氧化氮和一氧化氮合酶含量的变化及意义

目的　探讨癫疒间 患儿血清一氧化氮 (NO)、一氧化氮合酶 (NOS)的变化及意义。方法　利用ELISA方法 ,测定 5 8例癫疒间 患儿 (癫疒间 组 )和 2 3名健康儿童 (对照组 )血清中NO、NOS的含量 ,并分组比较不同条件下其含量的变化。结果　癫疒间 组血清NO、NOS的含量分别为 (5 .86± 1.2 1) μmol/ml和 (2 8.2 6± 8.4 9)U/ml,较对照组的 (3.78± 0 .74 ) μmol/ml及 (17.86± 4 .5 8)U/ml明显升高 (P <0 0 1) ;发作近期为 (7.31± 1.2 7)μmol/ml和 (31.2 5± 11.35 )U/ml,明显高于发作间期 (4 .2 7± 0 .6 6 ) μmol/ml和 (2 4 .15± 7.85 )U/ml(P <0 0 1) ;癫疒间 组EEG异常者为 (7.18± 1.35 ) μmol/ml和 (34.4 8± 8.5 6 )U/ml,明显高于EEG正常者 (4 .0 4± 0 .75 ) μmol/ml和 (2 2 .85± 7.4 5 )U/ml(P <0 0 1) ;但与发作类型、病程及是否接受治疗无关 (P >0 0 5 )。结论　癫疒间 发作近期血中NO、NOS生成增加 ,NO作为内源性调质参与癫疒间 发作病理生理过程     

诱导型一氧化氮合酶在脑胶质瘤中的表达及意义

目的:探讨诱导型一氧化氮合酶(ｉＮＯＳ)在脑胶质瘤的中表达及意义。方法:检测４Ｏ例脑胶质瘤中ｉＮＯＳ蛋白,分析ｉＮＯＳ与胶质瘤恶性程度的相关关系。结果:①对照组无ｉＮＯＳ表达,胶质瘤组ｉＮＯＳ阳性表达率为６２．５%;②低恶性与高恶性度肿瘤ｉＮＯＳ表达不同;③胶质瘤恶性程度与ｉＮＯＳ染色深浅及阳性细胞数百分比之间呈正相关关系。结论:ｉＮＯＳ产生的ＮＯ参与了胶质瘤从低恶性度向高恶性转化的发展过程,对实体脑肿瘤的生长及侵袭有重要作用,是高级别肿瘤区别于低级别肿瘤的一个重要的病理学特点。     

Fall in density, but not number of myenteric neurons and circular muscle nerve fibres in guinea-pig colon with ageing

Abstract  In guinea-pig ileum, ageing has been associated with a decrease in enteric neurons. This study examined guinea-pig colon and measured changes in gut dimensions, neuron size, density and ganglionic area. Changes in motor nerve fibres in the circular muscle were also measured. Myenteric neurons in whole-mount preparations of mid-colon from 2-week, 6-month, and 2-year-old guinea-pigs were labelled immunohistochemically with the neuronal marker human neuronal protein HuC/HuD, and numbers of neurons mm⁻², neuronal size, ganglionic area mm⁻², gut length, circumference and muscle thickness were measured. Corrected numbers of neurons mm⁻² and ganglionic area mm⁻² accounting for growth of the colon were calculated. Additionally, nerve fibres in circular muscle cross-sections were labelled with antibodies against nitric oxide synthase (NOS) and substance P (SP) and the density of nerve fibres in circular muscle was measured. The numbers of neurons mm⁻² decreased by 56% (from 2 weeks to 2 years) with no change in neuron size. Total neuron numbers decreased by 19% ( P  = 0.14) when adjusted for changes in length and circumference with age. The percentage area of NOS- and SP-immunoreactive (IR) nerve fibres in the circular muscle decreased ( P  < 0.001), but the total area of NOS and SP-IR nerve fibres increased ( P  < 0.01) due to an age-related increase in muscle thickness. The density of myenteric neurons in guinea-pig mid-colon halved from 2 weeks to 2 years, but when the increase in colon dimensions was considered, the number of neurons decreased by only 19%. The percentage area of motor nerve fibres in the circular muscle decreased with no change in total volume of nerve fibres.     

人工合成E-选择素对大鼠局灶性脑缺血再灌注损伤后脑组织一氧化氮合酶表达的影响

目的 探讨人工合成E-选择素对大鼠局灶性脑缺血/再灌注（I/R）损伤后脑组织一氧化氮合酶（NOS）及血清一氧化氮（NO）含量的影响.方法 采用改良的Zea Longa法建立脑I/R损伤模型.66只雄性SD大鼠随机分为对照组、模型组和人工合成E-选择素治疗组（治疗组）.治疗组大鼠采用股静脉注射人工合成E-选择素10 mg·kg-1.应用硝酸盐还原法测定血清中NO含量和免疫组化法检测缺血区脑组织神经型一氧化氮合酶（nNOS）、诱导型一氧化氮合酶（iNOS）阳性细胞数.结果 ①NO：以对照组NO含量为正常生理数据,模型组脑缺血2h/再灌注2～24h NO含量呈上升趋势,24 h时达高峰,72 h有所降低但仍高于对照组,各时间点与对照组比较明显增高（P＜0.01）;治疗组NO变化趋势同模型组,NO含量较模型组减少（P＜0.05）,较对照组增多（P＜0.01）.②NOS：以对照组nNOS、iNOS阳性细胞数为正常生理数据,模型组nNOS阳性细胞在脑缺血2h/再灌注2h后开始表达,12h达高峰,至24h开始降低,各时间点与对照组比较明显增高（P＜0.01）;模型组iNOS阳性细胞在脑缺血2h/再灌注2h开始出现,并持续增多,随时间延长呈上升趋势,24h达高峰,至72 h出现下降,各时间点与对照组比较明显增多（P＜0.01）;治疗组各时间点nNOS、iNOS阳性细胞变化趋势同模型组,但较模型组减少（P＜0.05）,较对照组增多（P＜0.01）.结论 大鼠脑I/R损伤后脑组织NOS活性表达增多,NO浓度升高导致脑组织损伤;人工合成E-选择素通过降低NOS表达,减少NO释放、减轻炎症反应和脑I/R损伤,起脑保护作用.