The effects of pentoxifylline on the generation of reactive oxygen species and lipid peroxidation in human spermatozoa

Summary. The aims of this study were to compare the in vitro effects of 3.6 mM and 7.2 mM pentoxifylline on the ability of spermatozoa to generate reactive oxygen species (ROS) and on lipid peroxidation (LPO). Semen samples were obtained from 10 asthenozoospermic men who had been previously identified as producing ROS after addition of Phorbol 12-myristate 13-acetate (PMA) during the screening of patients attending with male factor infertility. Spermatozoa were prepared by a swim-up technique from unprocessed semen and divided into 3 aliquots. To the control aliquot [A] an equal volume of BWW medium was added. To aliquots B and C an equal volume of BWW medium containing pentoxifylline was added to obtain final concentrations of 3.6 and 7.2 mM, respectively. ROS production was measured from peak luminescence (mV 10⁻⁷ sperm) using a lucigenin chemiluminescent probe. LPO was also measured in the medium surrounding the spermatozoa after 30 min exposure to pentoxifylline using the thiobarbituric acid (TBA) assay for malondialdehyde (MDA). The reduction in ROS production was significantly greater in the samples exposed to 7.2 mM pentoxifylline as compared with the control and 3.6 mM pentoxifylline samples. There was no significant difference in peak luminescence between control and 3.6 mM pentoxifylline specimens. Both concentrations of pentoxifylline caused comparable reductions in MDA concentration in the medium ( P <0.05) surrounding the spermatozoa compared with control after 30 min exposure. Extracellular ROS generation may damage surrounding healthy spermatozoa. These findings suggest that higher concentrations of pentoxifylline are protective against ROS release in susceptible spermatozoa and may also reduce collateral LPO.     

Effect of pentoxifylline on experimentally induced lipid peroxidation in human spermatozoa

We demonstrated previously that pentoxifylline in millimolar concentrations can inhibit superoxide anion production by human spermatozoa. In the present study we have examined the effects of the same concentrations of pentoxifjrlline on experimentally induced lipid peroxidation, as measured by malondialdehyde formation in the thiobarbituric (TBA) assay. Under the experimental conditions used, preincubation of spermatozoa with pentoxifjdline led to a significant dose-dependent stimulation (p<0.005) of malondialdehyde production amounting to 10.77 ± 2.35%, 13.45 ±2.99% and 17.4 ± 1.99% (mean ± SEM) for 1.9, 3.7 and 11.2 mmol/l pentoxifylline, respectively. In the presence of 11.2 mmol/l pentoxifylline, an increase in iron-catalysed lipid peroxidation potential was detected in samples of spermatozoa from 29 infertile men, regardless of their initial levels of malondialdehyde. The results of this study indicate that pentoxifylline might further augment the ferrous ion-stimulated decomposition of pre-accumulation lipid hydroperoxides in the sperm plasma membrane and thus promote malondialdehyde generation in the TBA assay.
It is concluded that the stimulatory effect of pentoxifjdline on iron-induced lipid peroxidation may have an adverse effect on the quality of sperm suspensions prepared for in vitro fertilization, a possibility which should be investigated further.     

脂质过氧化抑制剂对大鼠肾脏低温保存的保护作用

目的　探讨脂质过氧化抑制剂预处理对大鼠肾脏低温保存的作用及其机制。方法　对低温保存的大鼠肾脏进行脂质过氧化抑制剂U74 0 0 6F的预处理 ,观察肾组织中脂质过氧化代谢产物丙二醛含量及诱导型一氧化氮合酶表达水平的变化。结果　U74 0 0 6F预处理可降低肾组织氧化反应水平 ,减少诱导性一氧化氮合酶的表达。结论　U74 0 0 6F预处理通过抑制细胞脂质过氧化减轻氧化反应和细胞因子带来的损伤 ,对低温保存的肾脏起到保护作用     

脂质过氧化抑制剂对大鼠肾脏低温保存和移植的保护作用

目的：探讨脂质过氧化反应对肾脏低温保存和移植的影响及其作用机制。方法：对大鼠肾脏低温保存和移植前进行脂质过氧化抑制预处理,观察移植肾脏功能和形态的变化,肾组织丙二醛（MDA）含量及白细胞介素－2（IL－2）、细胞间粘附分子－1（ICAM－1）、诱导型一氧化氮合酶（iNOS)的表达水平。结果：与对照组相比,治疗组肾脏形态和功能的异常均减轻,IL－2、ICAM－1、iNOS的表达水平和MDA含量明显降低,结论脂质过氧化抑制剂可减轻细胞脂质过氧化反应,对移植肾脏的形态和功能起到保护作用。     

Effects of methylprednisolone and dextromethorphan on lipid peroxidation in an experimental model of spinal cord injury

Objective. This study examines the effects of agents purported to improve recovery following spinal cord trauma, methylprednisolone sodium succinate, dextromethorphan, and the combination of both, on the post-traumatic alterations of membrane lipid metabolism. Methods. After sparing ten rats for a control group (G1) and performing T3–T6 laminectomies in 150 rats, spinal cord injuries were accomplished in 120 of 150 Wistar rats with an aneurysmal clip compression at the level of T4-5 for 30 sec. Hence the G2 group (n 30) included the "only laminectomy/sham" group. The 120 injured animals were subdivided into four equal groups (n 30 each). Group G3 underwent no therapy, G4 methylprednisolone (MP), G5 dextromethorphan (DM), and G6 MP+DM therapies. Groups G2–G6 were killed ten by ten at 10 min, 30 min, and 120 min after the operation. We measured tissue (MDA) and blood malonyldialdehyde (MDAb), (a product of lipid peroxidation) levels as an indicator of oxidative damage by thiobarbituric acid method and activity levels of antioxidant enzymes superoxide dismutase and glutathione peroxidase in erythrocytes. Intergroup and intragroup results were compared statistically. Results. Methylprednisolone was able to keep the levels for all parameters close to baseline except for 30-min MDA, MDA_b, and SOD values. But their results were all different from those of G3. Dextromethorphan was successful in this respect at 30-min GSH-Px and 120-min SOD and GSH-Px, and all values were also different from G3 values except for 10-min MDA, SOD, and GSH-Px. Combined therapy was not able to keep levels close to baseline for all parameters, but they were different from G3's except for the GSH-Px values. Methylprednisolone values displayed minimal alterations according to baseline at 120 min. Dextromethorphan was relatively unsuccessful at 10 min. Combined therapy did not show benefit superior to MP/DM single therapies. Electronic Publication     

Effect of lipid peroxidation on beating frequency of human sperm tail

Summary. The tail beat frequency (TBF) of sperm was measured with a sperm-head fixation method which was based on the tendency of sperm to attach its head to the surface of a glass slide. Ferrous sulphate, a promotor of lipid peroxidation, inhibited TBF within 5 min of mixing with sperm. This inhibition can be reversed dose-dependently by superoxide dismutase, catalase, glutathione, and albumin. It was concluded that TBF could be a new pharmacological model for studying the effect of lipid peroxidation and antioxidant on sperm motility. Both enzymatic and non-enzymatic antioxidants can be screened with this method.     

The effect of pentoxifylline on penile cavernosal tissues in ischemic priapism-induced rat model

Introduction

Priapism is defined as persisting (>4 h), painful and abnormal tumescence that can occur without sexual stimulation. Three subtypes priapisms are seen—the non-ischemic priapism, intermittent and the ischemic priapism. In ischemic priapism, there is an abnormality in the veno-occlusive mechanism, resulting in venous stasis and accumulation of deoxygenated blood within the penile cavernosal tissue. Cavernosal tissue necrosis develops after extended period of ischemia and is eventually replaced by fibrotic tissue. It may results in erectile dysfunction if not treated promptly. Although, standard treatment of the ischemic priapism is penile aspiration and intracavernosal alpha-adrenergic agents, new oral agents have been investigated to reduce the cavernosal damage. In this study, the effect of different doses of pentoxifylline on cavernosal tissues was evaluated.

Materials and methods

Thirty-six male Wistar albino rats, age 5.5–6 months and weighing 250–300 g, were used in this study. The rats were randomly divided into five groups. In Group 1 (n = 7), the control group, only penectomy was performed. In Group 2 (n = 8), after 1 h of ischemic priapism, penectomy was performed. Group 3 (n = 7) received daily a 10 mg oral pentoxifylline for 4 weeks after 1 h of ischemic priapism, group 4 (n = 7) received a daily 30 mg oral pentoxifylline for 4 weeks after 1 h of ischemic priapism, and group 5 (n = 7) received a daily 100 mg oral pentoxifylline for 4 weeks after 1 h of ischemic priapism. At the completion of a 4-week period, penile tissues were obtained. Before penile tissues were obtained, intracavernosal pressures measured with electrical field stimulation and smooth muscle collagen ratio were evaluated pathologically.

Results

Electrical field stimulation-induced intracavernosal relaxation decreased in group 2 compared with group 1 (p < 0.05). Electrical field stimulation-induced relaxation enhanced in the group 3, 4 and 5 compared to group 2 (p < 0.05). In group 2, the collagen density was significantly higher than group 1. Administration of pentoxifylline reduced the collagen density caused by ischemic priapism in groups 3, 4 and 5 compared with group 2.

Conclusion

The results of the present study showed that ischemic priapism caused damage in the penile tissues of rats, and treatment with pentoxifylline reduced the harmful effects of ischemic priapism.     

瑞芬太尼预先给药对兔心肌缺血再灌注时脂质过氧化反应的影响

目的 评价瑞芬太尼预先给药对兔心肌缺血再灌注时脂质过氧化反应的影响.方法 家兔40只,雌雄不拘,体重1.5～2.5 kg,随机分为5组(n=8),Ⅱ组、Ⅲ组和V组采用静脉注射垂体后叶素2.5 U/kg的方法制备急性心肌缺血模型,Ⅰ组和Ⅳ组给予等容量生理盐水.Ⅲ组静脉注射吗啡3.3 mg/kg后30 min给予垂体后叶素前;Ⅳ组静脉输注瑞芬太尼3.3μg·kg-1·min-130 min时给予生理盐水;V组静脉输注瑞芬太尼3.3μg·kg-1·min-1 30 min时给予垂体后叶素.于给予垂体后叶素前即刻(T1)、给予垂体后叶素后24 h(T2)、48 h(T3)时采集颈内静脉血样,测定血清心肌肌钙蛋白I(cTnI)浓度.取心肌组织,测定超氧化物歧化酶(SOD)活性及丙二醛(MDA)含量.电镜下观察心肌组织超微结构.结果 与Ⅰ组比较,Ⅱ组血清cTnI浓度和心肌组织MDA含量升高,心肌组织SOD活性降低(P＜0.01);与Ⅱ组比较,Ⅲ组及V组血清cTnI浓度和MDA含量降低,心肌组织SOD活性升高(P＜0.05或0.01).电镜下Ⅴ组心肌损伤程度轻于Ⅱ组.结论瑞芬太尼预先给药可抑制脂质过氧化反应,从而减轻兔心肌缺血再灌注损伤.     

氨溴索预先给药对单肺通气患者炎性反应及脂质过氧化反应的影响

目的 评价氨溴索预先给药对单肺通气患者炎性反应及脂质过氧化反应的影响.方法 选择开胸手术患者45例,年龄37～64岁,体重53～65 kg,ASAⅠ或Ⅱ级,随机分为3组(n=15),双肺通气组(TLV组)、单肺通气组(OLV组),单肺通气+氨溴索组(OLV+AMB组)于单肺通气前25 min开始静脉输注氨溴索1 mg/kg(100 ml,4 ml/min),TLV组和OLV组静脉输注等容量生理盐水.OLV组和OLV+AMB组于麻醉诱导前(T0)、单肺通气前即刻(T1)、单肺通气0.5 h(T2)、1 h(T3)、2 h(T4)、恢复双肺通气后1 h(T5)、2 h(T6)和术后24 h(T7)时,TLV组于上述对应时点,采集桡动脉血样,测定血清TNF-α、IL-6、IL-8浓度和SOD活性,进行WBC和中性粒细胞(PMN)计数.结果 与TLV组比较,OLV组血清IL-6、IL-8、TNF-α浓度升高,SOD活性降低,WBC和PMN计数升高(P<0.05或0.01);与OLV组比较,OLV+AMB组血清IL-6、IL-8和TNF-α浓度降低,SOD活性升高,WBC和PMN计数降低(P<0.05或0.01).结论 氨溴索1 mg/kg预先给药可减轻单肺通气患者炎性反应及脂质过氧化反应.     

己酮可可碱预处理对大鼠供肝冷缺血损伤影响的实验研究

目的　探讨已酮可可碱预处理供者及肝脏对供肝冷缺血损伤的影响。方法　Wistar大鼠按处理方法的不同分为 4组 :对照组、供者预处理组 (实验 1组 )、供肝预处理组 (实验 2组 )、供者及供肝联合预处理组 (实验 3组 ) ,预处理使用己酮可可碱。各组动物均在供肝冷保存 6h后行原位肝移植 ,门静脉血流恢复后第 30min、3h及 2 4h取门静脉血测定肿瘤坏死因子 (TNF α)、丙氨酸转氨酶(ALT)、天冬氨酸转氨酶 (AST)及谷胱甘肽S转移酶 (GST)的水平。结果　门静脉复流后 30min、3h时血清TNF α水平 ,各实验组明显低于对照组 ,实验 3组显著低于实验 1组及实验 2组 (P <0 .0 5) ;30min及 3h时血清GST水平 ,各实验组明显低于对照组 (P <0 .0 5) ,实验 3组显著低于实验 1组及实验 2组 (P <0 .0 5) ;30min及 3h时血清ALT水平 ,各实验组明显低于对照组 ,实验 3组显著低于实验1组及实验 2组 (P <0 .0 5) ;2 4h时前述各指标各实验组明显低于对照组 ,实验 3组显著低于实验 2组 (P <0 .0 5) ;30min时血清AST水平 ,各实验组明显低于对照组 ,实验 3组显著低于实验 1组及实验 2组 (P <0 .0 5)。结论　己酮可可碱预处理对供肝的冷缺血再灌注损伤有一定的保护作用     

Effect of vitamin E on human sperm motility and lipid peroxidation in vitro

Aim: To assess the protective efficacy of vitamin E to counteract the reactive oxygen species (ROS) mediated damage onsperm motility, viability and lipid peroxidation. Melhods: Human semen samplns were obtained from the local hospi-tal. The split seminal fractions freed of seminal plasma v, ere reeonstimted in Ringer-Tymde and subjected to varied vita-min E concentrations (0.1-2 mmol/L), Results: Dose-dependent improvement in both motility and viability accom-panied by concomitant decrease in malondialdehyde (MDA an end product of lipid peroxidation) following vitamin Esuppllementation was noticed. Conclusion: Vitamin E protects against the ROS mediated damage on spermatozoa.Vimmth E supplementation could be of clinical importance for prolonged spermatozoal storage whenever needed.     

老年男性骨密度与脂质过氧化相关性研究

对９８例男性老年人的骨密度、血清超氧化物歧化酶（ＳＯＤ）、过氧化脂质（ＬＰＯ）、丙二醛（ＭＤＡ）、谷光甘肽（ＧＳＨ）进行测定，旨在研究老年人骨密度值变化与衰老的关系。结果：老年人ＢＭＤ、ＳＯＤ、ＧＳＨ随年龄增长逐渐减少，ＢＭＤ与ＳＯＤ、ＧＳＨ水平呈正相关，与ＬＰＯ、ＭＤＡ水平呈负相关。表明老年人骨密度与其衰老生化指标呈显著相关。老年人骨密度的丢失可作为衰老的重要指标之一。     

Evidence for only a moderate lipid peroxidation during ischemia-reperfusion of rat kidney due to its high antioxidative capacity

The extent of lipid peroxidation after ischemia-reperfusion (I-R) injury in rat kidney has been controversial. After I, xanthine oxidase (XO) is thought to be the main oxygen radical-generating system and malondialdehyde (MDA) is considered to be a marker of lipid peroxidation (LPO). In young rats (10 weeks old) a unilateral warm I of 40 and 60 min duration with subsequent R up to 1 h was conducted. Beside the “footprints” of oxidative stress, the cytosolic antioxidative capacity, expressed as superoxide anion (SOA) scavenging capacity, and the renal catalase were also investigated. There was only a moderate and transient increase of renal MDA 5 and 10 min after the onset of reoxygenation (133.57/70.67 and 97.84/91.57 vs. 49.47 nmol/g ww in preischemic controls). ATP breakdown (to 83/65 from 2947 nmol/g ww) with consecutive accumulation of hypoxanthine (up to 1105 nmol/g ww) at the end of ischemic period and the subsequent rapid decline of hypoxanthine by XO during reperfusion were used for an assessment of the SOA-generating capacity of these kidneys. Superoxide dismutase (SOD) activity, glutathione (GSH) and the high activity of catalase (18000 U/g ww) remained nearly unchanged during R. Only 1/25–1/50 of the kidney cytosol was able to scavenge the whole amount of SOA generated by the total XO activity of rat kidney. Thus, it could be analytically and stoichiometrically shown that after IR there is only a moderate oxidative stress in kidneys of young rats; this is due to their high SOA-scavenging capacity compared with their SOA-generating ability. Received: 7 August 1998 / Accepted: 9 October 1998     

The effects of memantine on lipid peroxidation following closed-head trauma in rats

Memantine is an uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist. Unlike other NMDA antagonists, it has been used clinically for years for the treatment of Parkinsons disease, spasticity, and dementia without serious side effects. We aimed to investigate the therapeutic efficacy of memantine on a closed head trauma model. A total of 132 adult male Sprague–Dawley rats were randomly divided into four groups: sham-operated, control (closed head trauma), sham-vehicle (closed head trauma + saline), treatment (closed head trauma + memantine, 10 mg/kg, i.p.). A cranial impact was delivered to the skull, just in front of the coronal suture, over the left hemisphere, from the height of 7 cm. Saline or memantine were applied 15 min after trauma. Rats were euthanased 0.5, 1, 2, 6, 24, 48 h after trauma. Brain tissue samples were taken 5 mm away from the left frontal pole and also from the corresponding point of the contralateral hemispheres. Malondialdehyde activity (MDA) was considered to reflect the degree of lipid peroxidation. The MDA levels continued to increase for the first 2 h after the injury, then started to decrease gradually. Memantine treatment significantly reduced lipid peroxidation levels in the treatment group compared with other groups (P<0.01). The findings of the present study indicate that memantine provides beneficial effects after closed head trauma in rats.     

Alpha-tocopherol and ginkgo biloba treatment protects lipid peroxidation during ischemic period in rat groin island skin flaps

Oxygen-derived free radicals have been implicated in the causation of cellular injury during low-flow ischemia and during reperfusion of previously completely ischemic tissue; they are also believed to be the causative factor in the no-reflow phenomena. Modulation of these free radical substances has been suggested as a means of decreasing the amount of tissue loss due to ischemia and subsequent reperfusion. Pretreatment of tissues with a variety of agents has been reported to minimize the production of oxygen radicals and augment tissue survival after an ischemic insult. Further evidence of free radical involvement in skin flap necrosis in a rat groin island skin flap model is presented. In addition, the effects of two different free radical scavengers, alpha tocopherol (20 mg/kg intraperitoneally once daily for a week) and ginkgo biloba (5 mg/kg orally twice a day for a week) have been investigated and compared. Since malonyldialdehyde (MDA) is the end product of lipoperoxidation which occurs in cellular membranes in an ischemic period - dependent manner, MDA levels in tissue homogenates were measured 60, 90, and 120 min after an ischemic insult. MDA levels significantly increased in a time-dependent manner during the ischemic period in the control group. Results from the determination of tissue MDA levels at biopsy sites of radical scavenger treated groups compared with the placebo group showed that the ginkgo biloba-treated rat samples had significantly lower MDA levels than control samples only at the 120 min ischemic period (p<0.01). However, protection of lipoperoxidation in alpha tocopherol-treated rat samples was detected after both the 90 and 12 min ischemic periods (p<0.01), and the magnitude of these decreased MDA levels in alpha tocopherol-treated samples was found to be greater than it was after ginkgo biloba treatment. Decreasing free radicals during reperfusion by using these agents, preferably alpha tocopherol, may be beneficial in modulating the no-reflow phenomenon and subsequent reperfusion injury, and may help to improve tissue salvage.     

已酮可可碱干预大鼠继发性脊髓损伤的实验研究

目的:探讨已酮可可碱(PTX)对大鼠继发性脊髓损伤的干预作用。方法:采用Allen重物打击法(W D)制作大鼠脊髓损伤模型,120只致伤SD大鼠分为3组,A组为单纯脊髓损伤组;B组为损伤后甲强龙(M P)干预组;C组为损伤后已酮可可碱(PTX)干预组。分伤后4h、8h、24h、3d、7d5个时间点,观测损伤部位脊髓组织的丙二醛、超氧化物歧化酶含量及病理形态,TUNEL标记细胞凋亡情况,比较各组间差别。结果:B、C组各时间点损伤部位脊髓组织中丙二醛含量较A组明显下降(P<0.05),超氧化物歧化酶含量较A组明显升高(P<0.05),病理形态改变较轻;B、C组凋亡细胞少于A组(P<0.05),B组和C组间无显著性差异(P>0.05)。结论:已酮可可碱可显著抑制氧自由基生成,减少神经细胞凋亡,对继发性脊髓损伤起到保护作用。     

Inhibition of lipid peroxidation by some dihydropyridine derivatives

The efficacy of dihydropyridine derivatives in inhibiting lipid peroxidation was studied using modified Buege and Austs method. The method first involves keeping a decapitated rat head at 37°C for 30min in order to induce global ischemia. Then, the cortex is removed and homogenized, and the homogenate is subsequently exposed to air for 30min for reoxygenation. Finally, the amount of thiobarbituric acid-reactive substances (TBAR) is measured. With this method, nisoldipine, nimodipine, nitrendipine, nifedipine and nicardipine were all shown to have an antioxidant activity that correlated with their lipophilicity, which was determined by their octanol/water partition coefficients.(Sakamoto A, Ohnishi S.T, Ogawa R: Inhibition of lipid peroxidation by some dihydropyridine derivatives. J Anesth 7: 193–197, 1993)     

Further evidence of lipid peroxidation in post-enteropathic haemolytic-uraemic syndrome

Lipid peroxidation may play a role in the pathogenesis of the haemolytic-uraemic syndrome (HUS). Thirteen children with the post-enteropathic form of HUS were studied using conjugated diene lipids as markers of in vivo lipid peroxidation. Levels of total conjugated diene lipids and 9,11-linoleic acid, the principal conjugated diene in human plasma, were greater in the acute phase of this disorder than in controls. The ratio of plasma vitamin E to lipid was lower than that in children with other renal diseases, and the expected positive correlation between vitamin E and lipids did not hold for HUS patients. These data provide further evidence of lipid peroxidation in HUS and a disturbance in the metabolism of the principal lipid-bound anti-oxidant vitamin E.     

非创伤性缺血预处理对肺缺血-再灌注损伤的保护作用

目的探讨非创伤性缺血预处理(N-WIP)对肺缺血-再灌注(I/R)损伤的保护作用。方法将40只新西兰大白兔随机分为对照组、I/R组、经典肺缺血预处理组(C-IP组)及非创伤性双下肢缺血预处理组(N-WIP组),每组10只。测定各组血氧分压(PaO2)、肺湿/干重比以及血清和肺组织中超氧化物歧化酶(SOD)的活性、丙二醛(MDA)的含量及谷胱苷肽过氧化物酶(GSH-PX)的活性。结果再灌注后,I/R组的PaO2逐步下降,以再灌注30min内下降速率最快,N-WIP组和C-IP组相应时段的PaO2优于I/R组(P<0.01);N-WIP组和C-IP组SOD和GSH-PX的活性均优于I/R组(P<0.01,P<0.05),肺湿/干重比和MDA的含量均低于I/R组(P<0.05,P<0.01)。结论非创伤性双下肢缺血预处理和经典肺缺血预处理均可以诱导机体产生同等强度的抗脂质过氧化作用,减轻缺血-再灌注对肺造成的损伤。