Evaluation of the role of L-arginine on spermatological parameters,seminal plasma nitric oxide levels and arginase enzyme activities in rams

The purpose of this study is to investigate the effects of L-arginine on spermatological parameters, seminal plasma nitric oxide levels and arginase enzyme activities. Fertile rams that are 2–3 years old and weighing 50–60 kg were used as material. The semen was collected by artificial vagina at 1st, 4th, 24th, 48th, 72nd, 96th and 120th hours for the control group before L-arginine administration. For treatment groups, L-arginine was administered intraperitoneally at a dose of 5 mg kg⁻¹ bw⁻¹ and semen was collected at the time point described for the control group. Spermatological characteristics of semen samples (semen volume, pH, sperm motility, concentration and abnormal sperm rate), seminal plasma nitric oxide levels and arginase enzyme activities were determined. Increased seminal plasma nitric oxide level (p < .01), seminal plasma arginase activity (p < .01), semen volume (p < .05), semen mass activity (p < .05), sperm motility (p < .05) and concentration (p < .01) and decreased abnormal sperm rate (p < .05 and p < .01) were observed by L-arginine administration. In conclusion, it may be concluded that L-arginine application in rams during the breeding season may have positive effects on rams' reproductive performance.     

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.     

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。     

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。     

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.     

Effect of diclofenac on semen quality: A review

Diclofenac is an effective nonsteroidal anti-inflammatory drug and one of the most prescribed medicines worldwide. So far, there are many published articles that directly link between diclofenac and semen quality; however, hitherto, there is no collective review or comprehensive discussion that reveal such imperative link. Therefore, this work reviews and judges the association between diclofenac administration and semen quality, henceforth male infertility. As a tool to accomplish this scientific input, Scopus, Embase and PubMed databases have been searched for all original articles using the keywords “diclofenac” versus “semen” and “sperm” since August 1987 through November 2020. In summary, diclofenac appears to induce negative effects on both qualitative and quantitative measures of sperm; however, this conclusion requires confirmation by human studies. The detected negative effects of diclofenac on semen quality measures may be owed to reduced levels of gonadal hormones, decreased antioxidant defence mechanism, increased oxidative stress, altered concentrations of nitric oxide that are required to maintain normal sperm physiology and reduced synthesis of prostaglandins.     

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。     

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.     

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。     

The activity of inducible nitric oxide synthase in rejected skin xenografts is selectively inhibited by a factor produced by grafted cells

BACKGROUND: Production of nitric oxide (NO) by graft infiltrating macrophages has been suggested as an important effector mechanism of allograft rejection. Expression of the gene for the inducible NO synthase (iNOS) and the production of NO in rejected graft has been demonstrated in various models of allotransplantation. However, whether NO plays a role in rejection of skin xenografts has not been documented. METHODS: Explants of rejected skin allografts or xenografts (rat to mouse) were cultivated in vitro and the production of NO, interleukin (IL)-2, IL-4, IL-10 and interferon-gamma (IFN-gamma) by graft infiltrating cells was determined by the Griess reaction or ELISA. Effects of supernatants from cultures of xenograft explants on the expression of gene for iNOS, accumulation of iNOS protein and NO production were determined by RT-PCR or Western blots. Molecular mass of the factor with the suppressive activity was characterized by filtration on chromatography Sephacryl S-200 Superfine column. In addition, the effects of 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (AMT), a selective iNOS inhibitor, on survival of skin xenografts were tested. RESULTS: While explants of rejected mouse skin allografts produced substantial amounts of NO, undetectable or only very low levels of NO were found in supernatants from cultured rat skin xenografts. Cocultivation of bacterial lipopolysaccharide (LPS)-stimulated mouse macrophages which produce high quantities of NO, with pieces of rejected xenografts, but not of syngeneic grafts, allografts or normal rat skin, completely inhibited production of NO. Production of IL-6 and IL-10 by LPS-stimulated macrophages was not inhibited under the same conditions. The inhibition of NO production was mediated by a factor which was produced by rejected rat xenograft and which was eluted from chromatography Sephacryl S-200 Superfine column in a fraction representing a molecular mass of 67 kDa. The factor did not inhibit the expression of the gene for iNOS, reduce the level of iNOS protein in stimulated macrophages, or function as a scavenger of NO. Rather, the factor inhibited the function of iNOS. The finding that NO does not play an important role during rejection of skin xenografts is supported by the observation that treatment of graft recipients with AMT, a specific iNOS inhibitor, did not enhance xenograft survival, while the same treatment resulted in prolongation of survival of skin allografts. CONCLUSION: The results thus demonstrate that a 67-kDa molecule produced by rejected rat skin xenografts selectively inhibits iNOS activity in graft infiltrating macrophages. We suggest that NO does not play a significant role in rejection of skin xenografts as it does in the case of allograft rejection.     

Caffeine increased progressive motility of human spermatozoa in normozoospermic and asthenozoospermic semen samples and enhanced activity of seminal creatine kinase

Even though the effect of caffeine on humans' health has been revealed in various research studies, its effect on semen quality has yet to be well explained. Here, we measured the effect of caffeine at 1, 5, 10 and 20 mM on motility of human spermatozoa in normozoospermic and asthenozoospermic semen samples, level of seminal nitric oxide, chelation of seminal calcium ions and activity of seminal creatine kinase. Fifty-one normozoospermic and ten asthenozoospermic semen samples were recruited in this study. Sperm motility was evaluated by Makler counter, and seminal nitric oxide, seminal-free calcium and activity of seminal creatine kinase were measured spectrophotometrically. Caffeine at 10 mM significantly (p < .05) increased progressive motility of spermatozoa in both tested groups. Also, caffeine significantly increased (p < .05) activity of creatine kinase and insignificantly (p > .05) altered nitric oxide and free calcium levels in seminal plasma. In conclusion, progressive motility of human spermatozoa was found to be higher in the presence of caffeine at 10 mM in normozoospermic and asthenozoospermic semen samples; this increase, albeit partially, could be due to increased activity of seminal creatine kinase, but not to increased production of nitric oxide or chelation of free calcium ions.     

The relationship between varicocele and semen nitric oxide concentrations

We investigated the relationship between seminal plasma nitric oxide (NO) concentrations and conventional semen parameters in patients with varicocele. Semen samples were obtained from infertile patients with varicocele (n=55) and from normal controls (n=48). The mean NO concentration in the seminal plasma of patients with varicocele was significantly higher than that of the controls (P < 0.01). A significant negative correlation was noted between NO and sperm motility (r=−0.29, P=0.003), NO and sperm concentration (r=−0.26, P=0.008) and NO and normal morphology (normal %) (r=−0.25, P=0.01). It was concluded that increased NO production may influence sperm production, motility and morphology in patients with varicocele. Received: 21 February 2000 / Accepted: 20 June 2000     

Evaluation of semen quality in 1808 university students,from Wuhan,Central China

The aim of this study was to evaluate the semen quality of university students in Wuhan, the largest city in the world in terms of the number of university students. All student sperm donors recorded in the Hubei Province Human Sperm Bank from 1 March 2010 to 31 December 2013 were screened. At last, a total of 3616 semen samples from 1808 university student sperm donors were eligible and retrospectively analyzed. Each donor''s semen parameters were averaged over two samples and compared with the World Health Organization criteria, and a generalized linear regression model was used to examine several determinants of semen quality. We found that the mean and median values were 3.0 ml and 2.8 ml for semen volume, 50.2 × 10⁶ ml⁻¹ and 50.0 × 10⁶ ml⁻¹ for sperm concentration, 148.1 × 10⁶ and 142.1 × 10⁶ for total sperm count, and 58.6% and 60.0% for total sperm motility. About 85.0% of donors had parameters that were all normal. Season and duration of abstinence were critical factors affecting semen quality. We also found a decrease in sperm concentration during the 4 years observation; however, this may not be a strong evidence to confirm the declining trend of semen quality. In conclusion, semen quality of university students in Wuhan was not optimal and should be paid high attention, long-term observation and further study should be carried out to confirm the present situation.     

Regulation of nitric oxide synthesis in uraemia

Nitric oxide (NO) is a cell-to-cell mediator involved in theregulation of vascular tone and in the mechanisms of host defence.Since uraemic syndrome is characterized by abnormalities inblood pressure and flow and by impairment of white cell function,we studied the regulation of nitric oxide synthase (NOS) activityby uraemic plasma. We used three different cellular types havingdifferent levels of NOS activity: tEnd. 1 murine endothelialcell line transformed by mT oncogene of polyomavirus had a highNOS activityand expressed endothelial-NOS (eNOS) and inducible-NOS(iNOS) isoforms; human endothelial cells from cord umbilicalvein (HUVEC) had low enzymatic activity and expressed only eNOS;finally, J774 murine macrophage line was characterised by iNOSinduced after treatment with cytokines. We demonstrated thatmost (79%) of end-stage uraemic plasma studied inhibited NOSactivity in tEnd.1 and in cytokine induced -J774, whereas theywere ineffective on HUVEC. Twenty percent of plasma samples(14 of 67) activated NOS activity in tEnd.1 and in J774 cells,but not in HUVEC, suggesting the presence of molecule(s) whichinfluence iNOS. The effect of plasma was not dependent on thetype of haemodialysis treatment. A great number of plasmas frompatients with moderate renal failure also inhibited NOS activityin tEnd.1, suggesting that the accumulation of molecules affectingNOS was caused by the renal failure rather than the haemodialytictreatment. However, the haemodialysis modified the effect of plasmas onNOS activity. Plasma taken after haemodialysis session showeda reduced inhibitory activity in tEnd.1 and in some cases itenhanced NOS activity. Simultaneously, molecules reducing NOSactivity accumulated in the ultrafiltrate. The plasma concentrationof N^G-N^G dimethyl-L-arginine (asymmetrical dimethylarginine,ADMA), an inhibitor of NOS, increased in end-stage uraemic patientsand was reduced by haemodialysis. However, the concentrationsreached in uraemic plasmas were lower than the ADMA ICM₅₀ ontEnd.1 NOS, indicating that this compound contributes with othermolecules to the inhibitory effect of uraemic plasma. Haemodialysisreduced also the enhanced effect exerted by some plasmas onNOS in J774. Therefore, the effect of endstage uraemic plasmaon NOS activity derive from the balance between inhibitors andactivators.     

Iron deficiency suppresses ileal nitric oxide synthase activity

Intestinal motility disorders are more common in women of childbearing age who are prone to iron deficiency anemia. The neurotransmitters nitric oxide (NO) and acetylcholine (ACh) play a key role in ileal smooth muscle relaxation and contraction, respectively. Iron-containing heme is known to be a cofactor for nitric oxide synthase (NOS), the enzyme responsible for NO production. Therefore we tested the hypothesis that iron deficiency would downregulate ileal NOS activity without affecting the ileum’s response to ACh. Twelve adult female prairie dogs were fed either an ironsupplemented (Fe+) (200 ppm) (n = 6) or an iron-deficient (Fe-) (8 ppm) (n = 6) diet for 8 weeks. Ileal circular muscle strips were harvested to measure responses to ACh and electrical field stimulation. Under nonadrenergic noncholinergic (NANC) conditions, Nω-nitro-L-arginine (L-NNA), an NOS inhibitor, and VIP_10-28, a vasoactive intestinal peptide (VIP) inhibitor, were added prior to electrical field stimulation. NANC inhibitory responses are expressed as a percentage of optimal relaxation from EDTA. The excitatory response to ACh was similar in both groups (1.1 ± 0.3 N/cm² vs. 1.5 ± 0.3 N/cm², P = 0.45). The inhibitory response to electrical field stimulation under NANC conditions was greater in the Fe+ group (34.7 ±2.9%) compared to the Fe-group (23.9 ±3.2%; P <0.01). L-NNA eliminated the inhibitory response in the Fe+ group (0.02 ± 0.02%) but not in the Fe-group (8.38 2 2.15%; P <O.Ol). VIP_10-28 led to greater relaxation in the Fe+ animals (45.8 ± 6.6%) than in the Fe-animals (23.4 ±5.8%; P <0.05). Both L-NNA and VIP_10-28 had no inhibitory response (0.02 ± 0.02%) in the Fe+ animals, whereas the Fe-animals had some residual inhibition (2.54 ±1.04%; P <0.05). These data suggest that ileal NANC relaxation is due to NOS and that iron deficiency results in (1) decreased NANC relaxation, (2) a compensatory relaxation due to a non-NOS, non-VIP mechanism, and (3) a normal excitatory response. We conclude that iron deficiency suppresses ileal NOS activity. Supported by grant ROI-DK44279-07 from the National Institutes of Health. Presented at the Forty-First Annual Meeting of The Society for Surgery of the Alimentary Tract, San Diego, Calif., May 2l–24, 2000.     

Paradoxical increase in nitric oxide synthase activity in hypercholesterolaemic rats with impaired renal function and decreased activity of nitric oxide.

BACKGROUND: We have shown that acute exposure of oxidized low-density lipoprotein (OX-LDL) induces vasoconstriction in renal vessels and reduces glomerular filtration rate (GFR) in an isolated perfused rat kidney model by decreasing the activity of nitric oxide (NO). L-arginine has a protective role against OX-LDl-induced vasoconstriction. Micropuncture studies have demonstrated that short-term diet-induced hypercholesterolaemia is associated with decreased GFR and renal blood flow and increased glomerular capillary pressure. This may be mediated by decreased activity of NO. METHODS: Rats were made hypercholesterolaemic by supplementing the standard chow with 4% cholesterol and 1% sodium cholate. A group of rats on hypercholesterolaemic diet also received L-arginine in the drinking water. After 4 and 6 weeks, blood samples and 24-h urine samples were collected for the measurement of biochemical parameters. After 6 weeks, all rats were subjected to isolated perfusion of kidneys at a constant pressure of 100 mmHg. During isolated perfusion, the unused contralateral kidney was taken for morphological studies and for assessing the activity of nitric oxide synthase enzyme by beta-NADPH diaphorase histochemistry. RESULTS: Rats fed a high-cholesterol diet had LDL levels 3-6 times greater than the rats fed standard chow. Rats that received L-arginine in the drinking water had serum L-arginine levels 5-6 times greater than control rats. At 6 weeks, creatinine clearance was significantly lower in the rats on the high-cholesterol diet compared to the rats on standard chow and rats on high-cholesterol diet plus L-arginine. Twenty-four-hour urinary total nitrate and nitrite excretion in the hypercholesterolaemic rats was 1.5-2 times greater than that of control rats. Twenty-four-hour urinary cGMP excretion was significantly lower in the rats on a high-cholesterol diet, but in the rats on high-cholesterol diet and L-arginine, 24-h urinary cGMP excretion was not significantly different from that of control rats. During isolated perfusion of kidneys, renal perfusate flow was found to be significantly reduced in the kidneys taken from the rats on a high-fat diet compared to controls. L-arginine supplementation in the drinking water almost completely reversed the effect of a high-fat diet. Inulin clearance was also significantly reduced in kidneys on a high-fat diet in contrast to controls but not in kidneys on high fat-diet and L-arginine. Basal cGMP excretion in urine was significantly lower in the kidneys taken from the rats on a high-fat diet compared to controls. L-arginine supplementation restored the basal cGMP excretion in these kidneys. NO synthase (NOS) enzyme activity as assessed by NADPH diaphorase activity showed that kidney sections taken from the rats on a high-fat diet showed more intense staining, indicating increased activity compared to the kidney sections taken from the rats on a normal diet. CONCLUSION: Though activity of NO is diminished in hypercholesterolaemic rats with impaired renal function, there is a paradoxical increase in NO production and NOS activity. L-arginine reverses the effects of a high-fat diet.     

Activity of nitric oxide synthase in mature and immature human spermatozoa

Nitric oxide (NO) is known to be involved in multiple signal transduction pathways of male germ cells, including sperm capacitation. In somatic cells, NO production was found to be part of apoptosis signalling. The aim of our study was to further clarify the role of NO in spermatozoa by investigation of NO synthase activity with regard to sperm maturity and sperm apoptosis signalling. Semen specimens from 19 healthy donors were subjected to density gradient centrifugation to separate the predominantly mature and immature sperm fraction. NO synthase activity was evaluated using diaminofluoresceine‐2‐diacetate by FACS. Apoptosis signalling was monitored by flowcytometric analyses of caspase‐3 (CP3) and integrity of the transmembrane mitochondrial potential (TMP). TUNEL assay was used to detect DNA fragmentations. Maturity of human spermatozoa was associated with increased NO synthase activity and inactivated apoptosis signalling (lower levels of disrupted TMP, active CP3 and DNA fragmentations, P < 0.05). Activation of apoptosis signalling was significantly negatively correlated to NO production, indicating a rather anti‐apoptotic effect of NO. This might underline the recently proposed role of NO in physiological sperm signal transduction, e.g. during capacitation.     

大鼠肝缺血／再灌注后肝组织一氧化氮和不同亚型一氧化氮合酶的变化

目的探讨一氧化氮（NO）和一氧化氮合成酶（NOS）在肝缺血／再灌注（I／R）过程中的变化和作用。方法健康雄性SD大鼠24只，随机分为3组（每组8只）：①正常对照组，术中只分离肝周围韧带，不做肝门阻断及再灌注。②I/R组，进行45min的部分肝门阻断及60min的再灌注。③L-精氨酸（L—Arg）组，缺血前20min经阴茎背静脉注射L—Arg（300mg／kg），余同②组。实验结束后，取下腔静脉血2ml，并迅速切取缺血肝组织。检测血清丙氨酸转氨酶（ALT）、门冬氨酸转氨酶（AST）、乳酸脱氢酶（LDH）；测定肝组织中超氧化物歧化酶（SOD）、丙二醛（MDA）、黄嘌呤氧化酶（XOD）、一氧化氮（NO）和一氧化氯合成酶（NOS）等指标；观察光镜和电镜下肝组织学变化。结果与正常对照组相比，I／R组iNOS升高，NO降低；L-Arg组NO、eNOS均高于I／R组。2、3组比1组大鼠的肝组织病理损害重、肝功能差，L—Arg组病理损害较I／R组明显减轻、肝功能改善。结论NO对大鼠肝I／R损伤具有保护作用．不同亚型NOS的变化参与其中。     

Pentoxifylline increases the level of nitric oxide produced by human spermatozoa

Pentoxifylline (PF) is a xanthine derivative drug primarily used to treat peripheral vascular disorders. It is currently used in assisted reproductive technologies to enhance human sperm motility. However, the mechanism by which this enhancement occurs is not fully understood. Given that nitric oxide has been identified as a trigger to sperm motion, we asked whether nitric oxide modulates the stimulatory effect of PF on sperm motility. A total of 41 semen samples from infertile males were studied. Nitric oxide production in the presence of 5 mm PF was tested using different bio‐analytical methods (spectrophotometry, fluorometry and fluorescence microscopy). The spectrophotometric determination showed higher levels of nitrite, an indirect measure for nitric oxide, in sperm samples supplemented with PF compared to controls. The fluorometric experiment showed higher 4, 5‐diaminofluorescein triazole, a product from the reaction between nitric oxide and 4, 5‐diaminofluorescein diacetate, after adding PF to spermatozoa. The fluorescence microscopy images of the spermatozoa supplemented with PF showed higher green fluorescence, indicating higher 4, 5‐diaminofluorescein triazole levels, compared to controls. It is concluded that PF enhances nitric oxide production in human spermatozoa, which explains, at least in part, the mechanism by which PF stimulates human sperm motility.     

精液FSH、LH、PRL和T水平与精子质量关系的研究

目的探讨人精液中性激素水平与精子质量的关系。方法参照WHO标准方法,进行精子密度、活动率检测,按不同密度和活动率分为4个组。采用ELISA法分析FSH、LH、PRL和T水平。用脱氧核苷酸末端转移酶(TdT)介导的缺口末端标记(TUNEL)法检测生殖细胞的凋亡。结果68例不育者精子密度和活动率随精液性激素水平减少而下降,呈显著性正相关(P均<0.01),生育组精液中FSH、LH、PRL和T水平分别为(1.73±0.15)mIU/ml、(2.28±0.21)mIU/ml、(6.44±0.30)ng/ml、(1.95±0.11)ng/ml,生殖细胞凋亡率为(4.71±1.23)%,与不育组(1.35±0.18)mIU/ml、(1.86±0.32)mIU/ml、(5.96±0.31)ng/ml、(1.55±0.13)ng/ml和(19.36±2.04)%相比有显著性差异(P<0.01)。不育组FSH、LH、PRL、T水平与生殖细胞的凋亡率呈显著性负相关(r分别为-0.89、-0.94、-0.91、-0.98)。结论精液低性激素水平可使睾丸生殖细胞凋亡率增加,精子密度和活率下降而致男性不育。