The changes in semen quality,arginase activity and nitric oxide level in dexamethasone-treated rams

This study was made to investigate the effects of intramuscular administrations of dexamethasone on seminal plasma nitric oxide levels and arginase activity, and some spermatological parameters in rams. Ten Akkaraman rams weighing 50–60 kg and 2 years old were used as material in this study. The study was performed during the breeding season (September–November) for rams. The semen was collected by artificial vagina at 1st, 4th, 24th, 48th, 72nd and 96th hours for control group before dexamethasone administration. For treatment group, 0.25 mg/kg dexamethasone was administered and semen was collected at the time points described for control group. Spermatological characteristics of semen samples (semen volume, pH, sperm motility, density and abnormal sperm rate), seminal plasma arginase enzyme activities and nitric oxide levels were determined. It was determined that the administration of dexamethasone was detected to decrease seminal plasma arginase activity (p < .05 and .01) and nitric oxide level (p < .05), semen volume (p < .05 and .01), mass activity (p < .05 and .01), sperm density (p < .05) and sperm motility (p < .05 and .01), and to increase abnormal sperm rate (p < .05 and .01). In conclusion, dexamethasone is not recommended to be used during the breeding season as it damages the sperm quality of the rams.     

Relationships between seminal plasma arginase activity and spermatological parameters in rams

This study was conducted to evaluate the correlation between seminal plasma arginase activity and spermatological parameters in rams. In this study, five fertility-proven Awassi rams were used as material. Six ejaculates were collected from each ram by an artificial vagina. Spermatological parameters (semen volume, mass activity, sperm motility and concentration and abnormal sperm rate) were immediately determined in each ejaculate. For enzyme assay, the semen samples were centrifuged and stored at -20 °C for the analysis of arginase activity. The average seminal plasma arginase activity was 0.61 ± 0.20 U (mg protein)(-1) . There was a positive correlation between arginase activity and semen volume (r = 0.412, P < 0.05), semen mass activity (r = 0.610, P < 0.01), sperm motility (r = 0.447, P < 0.05) and sperm concentration (r = 0.808, P < 0.01). However, there was a negative correlation between arginase activity and abnormal sperm rate (r = -0.424, P < 0.05). In conclusion, this study clearly suggests that there is a significant correlation between seminal plasma arginase activity and spermatological parameters. In light of these results, seminal plasma arginase activity may be a biochemical criterion for determining sperm quality besides classical semen analysis parameters in rams.     

白细胞精子症患者精液中一氧化氮和UA含量的关系分析

目的探讨白细胞精子症不育者精液中白细胞(WBC)密度、一氧化氮(NO)和尿酸(UA)之间的关系。方法依据WHO诊断标准,选择白细胞精子症不育者40例,非白细胞精子症不育者35例,生育者30例,采用过氧化物酶染色法进行精液WBC密度计数；采用镀铜镉还原荧光法检测NO代谢产物硝酸盐(NO_3)；UA含量测定采用尿酸酶。过氧化物酶偶联法。结果白细胞精子症组精液NO含量为(106．95±4．13)μmol/L、WBC为(1．985±0．696)×10~9/L,而UA含量(166．9±68．1)μmol/L,生育组NO含量(41．31±3．67)μmol/L、WBC为(0．038±0．024)×10~9/L和UA含量为(398．6±52．3)μmol/L。NO和WBC显著高于对照组,UA显著低于对照组(P＜0．01),UA与NO及WBC均呈显著性负相关(r=-0．795,P＜0．01：r=-0．857,P＜0．01)。结论白细胞精子症患者精液NO产生增多致UA含量下降,使精子中毒受损。提示临床在治疗时应加用抗氧化药物,可提高疗效。     

Significance of nitric oxide and its modulation mechanisms by endogenous nitric oxide synthase inhibitors and arginase in the micturition disorders and erectile dysfunction

Abstract:   Evidence indicates that nitric oxide (NO) deficiency contributes to micturition disorders, especially in the afferent pathway and erectile dysfunction (ED). Two possible causes of NO deficiency are substrate ( l -arginine) limitation and increased levels of endogenous inhibitors of NO synthase (particularly asymmetric dimethylarginine: ADMA) in plasma and tissues. Elevated tissues of ADMA and N^G-monomethyl-L-arginine (L-NMMA) have been reported to be associated with impaired NO-mediated urethral, trigonal and cavernosal relaxations by pelvic ischemia. Also, plasma ADMA may help to identify underlying cardiovascular disease in men with ED. Decreased l -arginine availability to NO synthase is due to the shunting of l -arginine into other pathways such as arginase. Interaction between NO synthase and arginase has been reported to be involved in NO-mediated urethral and prostatic relaxations. Also, increased arginase activity in cavernosal tissues likely contributes to the ED that accompanies diabetes mellitus and aging. Therefore, arginase inhibition has been reported to enhance the NO-dependent physiological process for erectile function.     

The role of nitric oxide in sepsis--an overview

Nitric oxide (NO) is normally produced in the endothelium by the constitutive isoform of the NO synthase. This physiological production of NO is important for blood pressure regulation and blood flow distribution. Several lines of evidence suggest that a hyperproduction of NO by the inducible form of NO synthase (iNOS) may contribute to the hypotension, cardiodepression and vascular hyporeactivity in septic shock. Lipopolysaccarides and cytokines, such as tumor necrosis factor, interleukin-1 and interferon-gamma, have been shown to induce iNOS in the endothelium, vascular smooth muscle cells, macrophages and different parenchymal cells. Treatment with inhibitors of NO synthesis has been shown to improve hemodynamic variables and survival in several animal models of septic shock. In human septic shock, inhibition of NO synthesis has been shown to alter hemodynamic variables in short-term studies, but it is uncertain whether this treatment has beneficial long-term effects. The aim of this review is to give an overview of the physiological role of NO and to discuss the role of NO in sepsis and the potential therapeutic implications of NO as a target in treatment of human septic shock. A main new aspect of this review is a critical discussion of previous reports measuring plasma nitrite/nitrate during septic shock and an evaluation of the validity of interpreting these data as evidence for a hyperproduction of NO. This review also emphasizes that many septic patients have preexisting endothelial dysfunction and lung diseases, which may contribute to adverse effects by systemic inhibition of NO synthesis. Another new aspect of the present review is a focus on the lack of direct evidence of iNOS expression in human septic shock.     

L-arginine, the substrate of nitric oxide synthase, inhibits fertility of male rats

Aim: To examine the effect of L-arginine, the substrate of nitric oxide (NO) synthase, on reproductive function ofmale rats. Methods: Male rats were gavaged with either L-arginine (100 or 200 mg·kg~(-1)·d~(-1)), D-arginine (200mg·kg~(-1)·d~(-1)) or vehicle (0.9% NaCl) for seven consecutive days. Their sexual behaviour and fertility were evaluat-ed using receptive females. Results: L-arginine (200 mg/kg) had no significant effect on sexual competence (interms of sexual arousal, libido, sexual vigour and sexual performance). In mating experiments, the higher dose of L-arginine effectively and reversibly inhibited fertility, whilst the lower dose and the inactive stereoisomer D-arginine hadno significant effect. The antifertility effect caused by L-arginine was due to a profound elevation in the preimplantationloss mediated possibly by impairment in epididymal sperm maturation, hyperactivated sperm motility and sperm capaci-tation. Conclusion: Elevated NO production may be detrimental to male fertility     

Kidney damage after renal ablation is worsened in endothelial nitric oxide synthase -/- mice and improved by combined administration of L-arginine and antioxidants

Aim Reduction in nitric oxide (NO) levels during kidney failure has been related to the reaction of NO with superoxide anions to yield peroxynitrite which possesses the biological activity responsible for renal damage. However, stimulation of the NO pathway ameliorates the progression of kidney failure. Thus, it is unclear whether NO prevents or acts as the compound responsible for the cytotoxicity observed during kidney failure. Methods We evaluated the development of kidney failure in animals that were wild type and deficient in endothelial NO synthase (eNOS (?/?)) and tested the effects of an antioxidant treatment and NO precursors on the generation of superoxide anion and kidney failure parameters. Results In wild‐type mice, five‐sixths nephrectomy increased proteinuria from 3.0 ± 0.35 to 14.5 ± 0.76 mg protein/24 h (P < 0.05), blood pressure from 83.1 ± 1.8 to 126.6 ± 1.7 mmHg (P < 0.05), and superoxide production from 1.4 ± 0.6% to 74.3 ± 0.8% (P < 0.05). The effects of five‐sixths nephrectomy on the eNOS (?/?) mice were greater compared with wild‐type mice. Proteinuria increased from 6.7 ± 0.5 to 22.7 ± 2.0 mg protein/24 h (P < 0.05), blood pressure increased from 93.3 ± 0.9 to 151.2 ± 3.4 mmHg (P < 0.05), and superoxide production increased from 12.9 ± 0.5% to 99.8 ± 1.3% (P < 0.05). The nitrotyrosine levels were lower in eNOS (?/?) mice as compared to wild‐type mice. A combination of L‐arginine and antioxidant treatment ameliorated renal damage. The effect was improved in wild‐type animals. Conclusion Our data support the relevance of NO as an antagonist to superoxide in renal tissues and suggest that the loss of this mechanism promotes the progression of kidney failure.     

男性不育精液中NO与UA含量的关系

目的探讨人精液中一氧化氮(NO)与尿酸(UA)含量的关系,及对精子质量的影响。方法参照WHO标准方法,进行精液常规分析,按精子密度、活动率不同分为(正常、＜20、20～40、＞40) 4个组。采用镀酮镉还原荧光法检测NO代谢产物硝酸盐(NO_3~-)。采用尿酶一过氧化物酶偶联法检测精液尿酸含量。结果70例不育组精液中尿酸含量和NO含量为(236．4±47．8)μmol/L、(78．7±1．6)μmol/L与正常生育组(398．6±52．3)μmol/L、(41．8±1．6)μmol/L呈显著性差异(P＜0．01)。将尿酸含量与NO含量进行相关性分析,两者呈显著性负相关(r=-0．96,P＜0．05)。不育各精子密度和活动率组精液尿酸含量随精子密度及活动率增加而上升,NO含量随之下降(P＜0．01)。结论精液尿酸含量测定可作为评价精子受活性氧损害的重要指标,证明尿酸对活性氧尤其在医学领域极为重视的NO损害精子具有保护性作用。     

iNOS/NO对结直肠肿瘤发生发展的影响

一氧化氮（nitric oxide,NO）具有广泛的生物学活性。近年来发现一氧化氮（NO）、一氧化氮合成酶（nitric oxide synthase-2,NOS-2）与结直肠肿瘤的发生、发展密切相关,它与环氧化酶（cy-cloxygenase-2,COX-2）之间存在复杂的调控机制。对NO清除剂、NOS抑制剂和释放NO的非甾体抗炎药的研究为结直肠肿瘤的防治提供了一个思路。     

人精液中NO与TP、Alb及Tf含量的关系

目的 探讨人精液一氧化氮（NO）与总蛋白（TP）、白蛋白（Alb）和转铁蛋白（Tf）含量的关系。方法参照WHO标准方法，进行精液常规分析。采用镀铜镉还原荧光法检测N0代谢产物硝酸盐（NO3^-），用双缩脲法检测TP，溴甲酚绿法测定Alb，用免疫散射比浊法检测Tf含量。结果 不育活率异常组、少精子和无精子症组的NO含量明显高于正常生育组，TP、Alb和Tf含量明显低于正常生育组，两组之间存在高度显著性差异（P〈0.01），不育组NO含量与TP、Alb和Tf含量呈显著性负相关（r=-0．88、r=-0．98、r=-0．68，P均〈0．05）。结论 精液蛋白质含量测定有助于精子质量的评价，对男性不育症的诊治有一定的指导意义，NO对精子运动能力及蛋白质的分泌利用有抑制作用，这对不育症的机制研究有重要价值。     

一氧化氮及一氧化氮合酶与吗啡耐受关系的新进展

疼痛治疗中长期给予吗啡易导致严重的耐受问题.多年来,针对耐受机制的研究表明NMDA/NO级联反应参与耐受的发生及发展.一氧化氮(nitric oxide,NO)主要是由一氧化氮合酶(nitric oxide synthase,NOS)催化其惟一前体--L-精氨酸生成NO和瓜氨酸.研究者们证实了大鼠鞘内吗啡耐受后脊髓内NOS尤其是nNOS的表达增高,耐受机制主要通过N-甲基-天门冬氨酸(N-methyL-D-aspartate,NMDA)受体的激活以及胞内钙离子浓度的升高来调节NOS的活性而触发NMDA/NO级联反应,继而影响耐受的发展.诸多研究给予吗啡的同时给予NOS抑制剂可以阻止耐受的发生,甚至在耐受形成后应用NOS抑制剂也可以翻转已经建立的耐受.但证实NOS各亚型在耐受中的具体作用仍不明确,需开展相关的研究进一步阐述其间的关系.     

Effects of H2O2 exposure on human sperm motility parameters,reactive oxygen species levels and nitric oxide levels

Research has revealed that reactive oxygen species (ROS) negatively affect sperm function, both in vivo and in vitro. Sperm preparation techniques for assisted reproductive technologies (ART) are potential causes for additional ROS production. This study aimed to correlate the concentration of exogenous H₂O₂ with sperm motility parameters and intracellular ROS and nitric oxide (NO) levels to reiterate the importance of minimising ROS levels in ART. Human spermatozoa from 10 donors were incubated and exposed to different exogenous H₂O₂ concentrations (0, 2.5, 7.5 and 15 μm ). Subsequently, motility was determined using computer‐aided semen analysis, while ROS (2,7‐dichlorofluorescin diacetate) and NO (diaminofluorescein‐2/diacetate) were analysed using fluorescence‐activated cell sorting. Results showed that H₂O₂ did affect the sperm parameters. Exogenous H₂O₂ was detrimental to motility and resulted in a significant increase in overall ROS and NO levels. A significant increase in static cells was seen as well. It is important to elucidate the mechanisms between intracellular ROS levels with sperm motility parameters. While this experiment demonstrated a need to reduce exogenous ROS levels during ART, it did not illustrate the cause and effect relationship of intracellular ROS and NO levels with sperm motility. Further research needs to be conducted to define a pathological level of ROS.     

Effect of hemodialysis on plasma nitric oxide levels

Nitric oxide (NO) is produced in excess in various pathological states, including sepsis and hepatic cirrhosis, and appears to be related to inflammatory status. In uremia, one would expect the levels of NO to increase. We aimed to determine whether hemodialysis (HD) would remove NO from the systemic circulation of uremic patients. Blood was collected before, after, and 1 day after HD from 12 uremic patients. Plasma nitrite and nitrate (NOx-) levels were measured by colorimetric Greiss reaction and cGMP was measured by an enzyme immunoassay kit. Our study demonstrated that uremic patients have high plasma NO levels, and HD led to a significant drop in plasma NOx- level (63 +/- 15% reduction). The level rose back to the pre-HD level on the following day. Plasma cGMP in the patients also decreased significantly after HD (27 +/- 14% reduction). In conclusion, we hypothesized that HD might be a possible approach for the removal of excess NO in pathological conditions such as sepsis and hepatic cirrhosis.     

Aspirin decreases human sperm motility and vitality,chelates seminal calcium,but insignificantly reduces seminal nitric oxide production

Lately, there is a systematic research consensus that reveals adverse effects of aspirin on semen quality characteristics; however, such consensus is lacking further confirmation by human studies. Therefore, here, we asked whether sperm motility and vitality are affected in the presence of aspirin at 0.1 and 1 mM in the ejaculated semen, and whether such effect may be due to an alteration in seminal calcium ions or seminal nitric oxide production. Forty-three semen samples from different normozoospermic men were recruited in this study. Sperm motility was measured by Makler counting chamber, and sperm vitality was measured by Eosin test. Calcium chelating effect of aspirin and seminal nitric oxide production was measured spectrophotometrically. Aspirin at both tested concentrations significantly (p < .05) reduced progressive grade-a motility and vitality of spermatozoa. Additionally, aspirin was found to have significant ability (p < .05) to bind seminal calcium ions, but insignificantly reduced the amount of seminal nitric oxide. In conclusion, sperm motility and vitality were reduced in the presence of aspirin at 0.1 and 1 mM in semen. Such reduction may be attributable to the ability of aspirin to chelate seminal calcium ions, but not to an alteration in the amount of nitric oxide produced.     

The role of nitric oxide in cardiac surgery

The release of nitric oxide (NO) from coronary endothelial cells is impaired following reperfusion; however, several experimental studies have found that it exerts a cardioprotective effect during myocardial ischemiareperfusion. Thus, attempts have been made to supplement NO production exogenously during reperfusion when endogenous NO release may be diminished. Conversely, other studies suggest that NO exacerbates reperfusion injury by inducing the production of peroxynitrite. NO has also been reported to provide beneficial effects as a selective pulmonary vasodilator to relieve pulmonary hypertension. A loss of NO-mediated relaxation caused by the dysfunction of endothelial cells is characteristic of intimal hyperplasia, and nitrosovasodilators have proven efficient against atherosclerotic coronary heart disease, which may be attributable to their antiplatelet effects as well as to vasodilation. Furthermore, protamine sulfate, which is rich inl-arginine, is thought to augment NO production by supplying exogenousl-arginine, or to act on endothelial cell receptors to stimulate the production of NO. This review summarizes the current role of NO in cardiac surgery.     

Improvement of penile erection, sperm count and seminal fructose levels in vivo and nitric oxide release in vitro by ayurvedic herbs

In the present study, the effect of four Vajikaran Rasayana herbs on penile erection, sperm count, seminal fructose content in vivo and nitric oxide (NO) release in vitro was assessed. Lyophilised aqueous extracts of Asparagus racemosus Willd. (AR), Chlorophytum borivilianum Sant. F. (CB), Curculigo orchioides Gaertn. (CO), and Dactylorhiza hatagirea (D. Don) Soo (DH) were orally administered at 100 mg/kg body weight to Wistar strain male albino rats. Penile erection index and sperm count were determined by visual observation; the seminal fructose concentration was measured spectrophotometrically using resorcinol reagent; and NO release was assessed in a mouse macrophage cell line (RAW264) spectrophotometrically using a commercial Griess reagent kit. Penile erection index, sperm count, seminal fructose concentration and in vitro NO release were the parameters measured. A significant effect on the sperm count, seminal fructose content and penile erection index was observed upon treatment with the extracts. The effect of extracts on inducible NO release in vitro directly correlated with the enhanced erectile function in vivo. The aphrodisiac claims attributed to the four Vajikaran Rasayana herbs were tested and a distinctive effect of all extracts tested was observed, with C. borivilianum showing a highly significant response for all parameters measured in vivo and in vitro. The present study also provides a good correlation between the in vivo improvement of penile erection and in vitro NO releasing activity of the extracts. Increase in seminal fructose levels and sperm count further validates the role of these herbs in improving reproductive function.     

Beneficial effects of statins on the microcirculation during sepsis: the role of nitric oxide

This review describes the laboratory evidence and microvascularmechanisms responsible for the beneficial effects of statinsin sepsis. During sepsis, changes occur within the microcirculationincluding alterations in arteriolar tone influencing blood pressure,adaptations to endothelial cell integrity causing leakage ofproteins and macromolecules, and adhesion and migration of leucocytesthrough the vascular endothelium. Statins are widely used ascholesterol-lowering agents, but appear to have anti-inflammatoryactions during sepsis. We have discussed the effects of statinson specific pathological processed within the microcirculationand focused on the role of nitric oxide (NO). The main mechanism by which statins appear to be an effectivetreatment for sepsis is increased expression of endothelialnitric oxide synthase (eNOS), in conjunction with down-regulationof inducible nitric oxide synthase. Combined, this results inan increase in physiological concentrations of NO, thus restoringendothelial function. Laboratory studies have therefore suggestedthat enhancement of eNOS activity during sepsis may lead torestoration of microvascular tone, maintenance of microvascularintegrity, and inhibition of cell adhesion molecules. However,other mechanisms independent of lipid-lowering effects, includingantioxidant activity and alterations in the development of vascularatherosclerosis, may also contribute to the beneficial effectsof statins. We have also addressed the influence on the effectsof statins of lipid solubility and pre- and pro-phylactic administration.     

男性不育症患者精浆一氧化氮与细胞因子相关性研究

目的：探讨男性不育症患者精浆一氧化氮（NO）与肿瘤坏死因子α（TNFα）、白介素6（IL－6）、白介素8（IL－8）的相互关系及其在发病中的作用。方法：测定男性不育症患者80例精浆中NO2^-、TNFα、IL－6、IL－8含量,并同健康已育男性对照。TNFα、IL－6、IL－8测定用ELISA法,二氧化氮离子（NO2^-）测定用萘乙胺盐比色法。结果：男性不育症患者精浆NO2^-、TNFα、IL－6、IL－8含量显著高于正常对照组（P＜0．01,P＜0．05）。NO2^-与TNFα、IL－6、IL－8呈正相关。结论：NO、TNFα、IL-6、IL－8参与男性不育症的发病,监测不育症患者精浆中NO及TNFα、IL－6、IL－8在诊断及治疗上有指导意义。     

外源性一氧化氮对前列腺癌细胞作用的研究

目的研究外源性一氧化氮(NO)对前列腺癌细胞株生长的影响及作用机制.方法以硝普钠(SNP)为一氧化氮供体,不同浓度的SNP作用前列腺癌细胞,采用MTT法测细胞的生存率,Tunel法和流式细胞仪检测细胞的凋亡情况,通过RT-PCR法检测细胞p21^waf1/cip1基因的表达.结果前列腺癌细胞生存率与低浓度的SNP成正比,而与高浓度的SNP成反比.高浓度的SNP可作用于细胞的G1期,诱导细胞凋亡,p21^waf1/cip1的表达也随之上调.结论低浓度的SNP促进前列腺癌细胞的生长;高浓度的SNP促进细胞的凋亡,p21^waf1/cip1的上调可能是高浓度的SNP诱导前列腺癌细胞凋亡的机制之一.     

左旋精氨酸对急性胰腺炎的作用

探讨左旋精氨酸（Ｌ－Ａｒｇ）在大鼠急性水肿性胰腺炎（ＡＥＰ）中的作用。方法观察倍数剂量Ｌ－Ａｒｇ治疗ＡＥＰ大鼠后,血浆和胰组织一氧化氮（ＮＯ）浓度、血浆淀粉酶、平均动脉压（ＭＡＰ）、胰组织病理的变化。结果ＡＥＰ大鼠血浆、胰组织ＮＯ浓度明显降低,Ｌ－Ａｒｇ５０、１００ｍｇ／ｋｇ升高血浆、胰组织ＮＯ浓度,改善了大鼠ＡＥＰ;Ｌ－Ａｒｇ８００、１６００ｍｇ／ｋｇ体重使ＮＯ浓度过度升高,加重ＡＥＰ成为急性出血坏死性胰腺炎（ＡＨＮＰ）;胰组织病理评分与血浆、胰组织ＮＯ浓度呈正相关。Ｌ－Ａｒｇ对ＭＡＰ的影响较小。血浆淀粉酶除８００ｍｇ／ｋｇ体重组明显降低外,其余各组间无明显差异。结论Ｌ－Ａｒｇ因升高ＮＯ浓度而参与了大鼠ＡＥＰ的病理过程。