Prostaglandin levels in seminal plasma and sperm extracts of the domestic turkey, and the effects of cyclooxygenase inhibitors on sperm mobility

Mating behaviors in ovoviviparous black rockfish (Sebastes schlegelii): molecular function of prostaglandin E2 as both a hormone and pheromone

Prostaglandins (PGs) are profound hormones in teleost sexual behavior, especially in mating. PGs act as pheromones that affect the olfactory sensory neurons of males, inducing the initiation of a series of mating behaviors. However, the molecular mechanism by which PGs trigger mating behavior in ovoviviparous teleosts is still unclear. In the present study, we employed the ovoviviparous black rockfish (Sebastes schlegelii), an economically important marine species whose reproductive production is limited by incomplete fertilization, as a model species. The results showed that when the dose of PGE2 was higher than 10 nmol/L, a significant (P < 0.05) increase in mating behaviors was observed. Dual-fluorescence in situ hybridization indicated that PGE2 could fire specific neurons in different brain regions and receptor cells in the olfactory sac. After combining with specific neurons in the central nervous system (CNS), a series of genes related to reproduction are activated. The intracerebroventricular administration of PGE2 significantly increased lhb levels (P < 0.05) in both sexes. Moreover, steroidogenesis in gonads was also affected, inducing an increase (P < 0.05) in E2 levels in males and T levels in females. PGE2 levels were also increased significantly (P < 0.05) in both sexes. The present study revealed that PGE2 can activate mating behavior in black rockfish in both hormone and pheromone pathways, leading to variations in sex steroid levels and activation of reproductive behaviors. Our results provide not only novel insight into the onset of mating behaviors in ovoviviparous teleosts but also solutions for the incomplete fertilization caused by natural mating in cage aquaculture.

Supplementary Information

The online version contains supplementary material available at 10.1007/s42995-023-00214-w.

Arachidonic Acid Pathways and Male Fertility: A Systematic Review

Arachidonic acid (AA) is a polyunsaturated fatty acid that is involved in male fertility. Human seminal fluid contains different prostaglandins: PGE (PGE₁ and PGE₂), PGF_2α, and their specific 19-hydroxy derivatives, 18,19-dehydro derivatives of PGE₁ and PGE₂. The objective of this study is to synthesize the available literature of in vivo animal studies and human clinical trials on the association between the AA pathway and male fertility. PGE is significantly decreased in the semen of infertile men, suggesting the potential for exploitation of PGE agonists to improve male fertility. Indeed, ibuprofen can affect male fertility by promoting alterations in sperm function and standard semen parameters. The results showed that targeting the AA pathways could be an attractive strategy for the treatment of male fertility.

Contaminants of Emerging Concern (CECs) and Male Reproductive Health: Challenging the Future with a Double-Edged Sword

Approximately 9% of couples are infertile, with half of these cases relating to male factors. While many cases of male infertility are associated with genetic and lifestyle factors, approximately 30% of cases are still idiopathic. Contaminants of emerging concern (CECs) denote substances identified in the environment for the first time or detected at low concentrations during water quality analysis. Since CEC production and use have increased in recent decades, CECs are now ubiquitous in surface and groundwater. CECs are increasingly observed in human tissues, and parallel reports indicate that semen quality is continuously declining, supporting the notion that CECs may play a role in infertility. This narrative review focuses on several CECs (including pesticides and pharmaceuticals) detected in the nearshore marine environment of False Bay, Cape Town, South Africa, and deliberates their potential effects on male fertility and the offspring of exposed parents, as well as the use of spermatozoa in toxicological studies. Collective findings report that chronic in vivo exposure to pesticides, including atrazine, simazine, and chlorpyrifos, is likely to be detrimental to the reproduction of many organisms, as well as to sperm performance in vitro. Similarly, exposure to pharmaceuticals such as diclofenac and naproxen impairs sperm motility both in vivo and in vitro. These contaminants are also likely to play a key role in health and disease in offspring sired by parents exposed to CECs. On the other side of the double-edged sword, we propose that due to its sensitivity to environmental conditions, spermatozoa could be used as a bioindicator in eco- and repro-toxicology studies.

The Role of Selected Natural Biomolecules in Sperm Production and Functionality

Emerging evidence from in vivo as well as in vitro studies indicates that natural biomolecules may play important roles in the prevention or management of a wide array of chronic diseases. Furthermore, the use of natural compounds in the treatment of male sub- or infertility has been proposed as a potential alternative to conventional therapeutic options. As such, we aimed to evaluate the effects of selected natural biomolecules on the sperm production, structural integrity, and functional activity. At the same time, we reviewed their possible beneficial or adverse effects on male reproductive health. Using relevant keywords, a literature search was performed to collect currently available information regarding molecular mechanisms by which selected natural biomolecules exhibit their biological effects in the context of male reproductive dysfunction. Evidence gathered from clinical trials, in vitro experiments and in vivo studies suggest that the selected natural compounds affect key targets related to sperm mitochondrial metabolism and motion behavior, oxidative stress, inflammation, DNA integrity and cell death. The majority of reports emphasize on ameliorative, stimulating and protective effects of natural biomolecules on the sperm function. Nevertheless, possible adverse and toxic behavior of natural compounds has been indicated as well, pointing out to a possible dose-dependent impact of natural biomolecules on the sperm survival and functionality. As such, further research leading to a deeper understanding of the beneficial or adverse roles of natural compounds is necessary before these can be employed for the management of male reproductive dysfunction.

Use of antioxidants and time of cold storage: effects over viability parameters and enzymatic levels in semen of rainbow trout (Oncorhynchus mykiss, Walbaum, 1792)

The cold storage of milt implies potentials alterations in its quality because the storage generates as main process, free radicals that produce spermatozoa membrane lipids damage with the consequent motility and fertilising capacity disruptions. To decrease the damage generated by free radicals the cells have antioxidant defences (proteins, enzymes, and low molecular weight substances). The objective of the present study evaluated the time storage effect and different antioxidants prepared in spermatic diluents on sperm viability of O. mykiss milt stored at 4°C. The two-way ANOVA denoted that the time storage and antioxidant influence have significant effects separated or combined on viability parameters (sperm motility and viability, proteins concentrations and superoxide dismutase enzymatic activity in seminal plasma). In contrast, only the storage time affected the fertilising capacity and catalase enzymatic activity in seminal plasma. The resulting analysis can conclude that the antioxidant presence improves the viability of cold stored milt, especially the transport conditions and the antioxidants allow the fecundity despite motility decrease.

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.

The Female Response to Seminal Fluid

Seminal fluid is often assumed to have just one function in mammalian reproduction, delivering sperm to fertilize oocytes. But seminal fluid also transmits signaling agents that interact with female reproductive tissues to facilitate conception and .pregnancy. Upon seminal fluid contact, female tissues initiate a controlled inflammatory response that affects several aspects of reproductive function to ultimately maximize the chances of a male producing healthy offspring. This effect is best characterized in mice, where the female response involves several steps. Initially, seminal fluid factors cause leukocytes to infiltrate the female reproductive tract, and to selectively target and eliminate excess sperm. Other signals stimulate ovulation, induce an altered transcriptional program in female tract tissues that modulates embryo developmental programming, and initiate immune adaptations to promote receptivity to implantation and placental development. A key result is expansion of the pool of regulatory T cells that assist implantation by suppressing inflammation, mediating tolerance to male transplantation antigens, and promoting uterine vascular adaptation and placental development. Principal signaling agents in seminal fluid include prostaglandins and transforming growth factor-β. The balance of male signals affects the nature of the female response, providing a mechanism of ‟cryptic female choiceˮ that influences female reproductive investment. Male-female seminal fluid signaling is evident in all mammalian species investigated including human, and effects of seminal fluid in invertebrates indicate evolutionarily conserved mechanisms. Understanding the female response to seminal fluid will shed new light on infertility and pregnancy disorders and is critical to defining how events at conception influence offspring health.

Age at mating and male quality influence female patterns of reproductive investment and survival

The trade-off between the allocation of resources toward somatic maintenance or reproduction is one of the fundamentals of life history theory and predicts that females invest in offspring at the expense of their longevity or vice versa. Mate quality may also affect life history trade-offs through mechanisms of sexual conflict; however, few studies have examined the interaction between mate quality and age at first mating in reproductive decisions. Using house crickets (Acheta domesticus), this study examines how survival and reproductive trade-offs change based on females' age at first reproduction and exposure to males of varying size. Females were exposed to either a large (presumably high-quality) or small male at an early (young), middle (intermediate), or advanced (old) age, and longevity and reproductive investment were subsequently tracked. Females mated at a young age had the largest number of eggs but the shortest total lifespans while females mated at older ages produced fewer eggs but had longer total lifespans. The trade-off between age at first mating and eggs laid appears to be mediated through higher egg-laying rates and shorter postmating lifespans in females mated later in life. Exposure to small males resulted in shorter lifespans and higher egg-laying rates for all females indicating that male manipulation of females, presumably through spermatophore contents, varies with male size in this species. Together, these data strongly support a trade-off between age at first reproduction and lifespan and support the role of sexual conflict in shaping patterns of reproduction.

(+)-Catechin and (-)-epigallocatechin gallate: are these promising antioxidant therapies for frozen goat semen?

ABSTRACT The aim of this study was to evaluate the effects of different concentrations of (+)-catechin or (-)-epigallocatechin gallate (EGCG) on goat semen freezability. Poolsof semen were processed (Experiment 1: 0, 15, 25, 50, 75, or 100µM (+)-catechin; Experiment 2: 0, 15, 25, 50, 75, or 100µM EGCG) and frozen. After thawing, the samples were evaluated for kinematics, plasma membrane (PMi) and acrosome integrity, morphology, and oxidative stress, at 0 and 1h. In Experiment 1, at 0h, VSL and VAP were greater (P<0.05) with 15µM than with 50 and 100; WOB was lower (P<0.05) with 100µM than with 0, 15, and 25; and BCF was higher (P<0.05) with 75 and 100µM than with 0. In turn, in Experiment 2, progressive motility was higher (P<0.05) with0 and 15µM than with50 and 75; LIN was lower (P<0.05) with75 and100µM than with0 and 15; WOB was higher (P<0.05) with0 and 15µM; and PMi was greater (P<0.05) with100µM than 0. Thus, (+)-catechin or EGCG at higher concentrations inhibits the kinematics of frozen goat sperm, in a transitory way, and 100µM of EGCG preserves the PMi.

Conservative Nonhormonal Options for the Treatment of Male Infertility: Antibiotics, Anti-Inflammatory Drugs, and Antioxidants

The nonhormonal medical treatment can be divided into empirical, when the cause has not been identified, and nonempirical, if the pathogenic mechanism causing male infertility can be solved or ameliorated. The empirical nonhormonal medical treatment has been proposed for patients with idiopathic or noncurable oligoasthenoteratozoospermia and for normozoospermic infertile patients. Anti-inflammatory, fibrinolytic, and antioxidant compounds, oligo elements, and vitamin supplementation may be prescribed. Infection, inflammation, and/or increased oxidative stress often require a specific treatment with antibiotics, anti-inflammatory drugs, and/or antioxidants. Combined therapies can contribute to improve sperm quality.

Asthenozoospermia and membrane remodeling enzymes: a new role for phospholipase A2

Phosholipase A2 (PLA2 ) activity in the seminal plasma and in sperm heads is closely related to sperm motility and male fertility. Therefore, the purpose of this study was to investigate the possible involvement of different isoforms of phospholipase in asthenozoospermia. To accomplish this, cPLA2 , phospho-cPLA2 , iPLA2 , and sPLA2 were evaluated by immunofluorescence and immunoblot analyses in spermatozoa obtained from 22 normozoospermic men and 28 asthenozoospermic patients. We found significant differences in cPLA2 and its phosphorylated/activated form, iPLA2 , and sPLA2 content and distribution in normal and asthenozoospermic patients. cPLA2 was localized in heads, midpieces, and tails of all spermatozoa as constitutive enzyme, less expressed in the tail of spermatozoa with low progressive motility. While active phospho-cPLA2 distribution was homogeneous throughout the cell body of control-donor spermatozoa, lower levels were detected in the tails of asthenozoospermic patients, as opposed to its strong presence in heads. Low immunofluorescence signal for iPLA2 was found in astenozoospermic patients, whereas sPLA2 was significantly lower in the heads of asthenozoospermic patients. Spermatozoa with low progressive motility showed differences both in terms of total specific activity and of intracellular distribution. cPLA2 , iPLA2 , and sPLA2 specific activities correlated positively and in a significantly manner with sperm progressive motility both in normozoospermic men and asthenozoospermic patients. In conclusion, PLA2 s are expressed in different areas of human spermatozoa. Spermatozoa with low motility showed differences in total specific activity and enzyme distributions. We speculated that PLA2 expression and/or different distribution could be potential biomarkers of asthenozoospermia, one of the major causes of male factor infertility.

Mating for male-derived prostaglandin: a functional explanation for the increased fecundity of mated female crickets?

Direct benefits are considered to be the driving force of high female mating rates, yet species in which females do not receive material resources from males still experience increased fitness from mating frequently. One hypothesis suggests that substances within the ejaculate may boost survival or offspring production. If these materials are limiting to females, they will require continual renewal via mating and could provide a functional understanding of how high mating rates lead to increased female fitness. Using the Texas field cricket, Gryllus texensis, we investigated the sexual transfer of prostaglandin E2, an important mediator of invertebrate reproduction. We determined that like other gryllid species, males include significant quantities of prostaglandin E2 (PGE2) and its precursor molecule, arachidonic acid (AA), within the spermatophore. These components are passed to females during copulation and then stored within the spermatheca. We then tested the novel hypothesis that PGE2 is ephemerally available after mating and that females must frequently mate to maintain access to this limiting compound. We found that PGE2 within the spermatheca is indeed depleted through time, with only a small amount remaining 1 week after mating, but that its presence can be maintained at high quantities and for prolonged periods of time by remating. Our results support the hypothesis that high female mating rates increase the amount and availability of PGE2 throughout the breeding season, which could explain the positive relationship between female mating rate and fecundity.

A unique mechanism of successful fertilization in a domestic bird

Fertilization is an indispensable step for formation of a zygote in sexual reproduction, leading to species survival. When mating occurs, sperm is transported to the female reproductive tracts via the seminal plasma (SP). SP is derived from male accessory sex glands and it plays pivotal roles for fertilization in animals. However, molecular mechanisms of SP or a fluid derived from male accessory sex glands for successful fertilization remain unclear. Here, we report that in male quail the cloacal gland (CG) produces prostaglandin F_2α (PGF_2α) that contributes to successful fertilization. PGF_2α, as well as the secretion of CG (CGS), induced vaginal contractions and caused the opening of the entrance of the sperm storage tubules, the structures responsible for the long-term sperm storage and fertilization. The removal of CGS from the male before mating reduced the fertility, but the supplementation of CGS or PGF_2α rescued the subfertility. We further showed that male CG contains glucose that is utilized as energy source for the intrinsic sperm mobility after transportation to female vagina. This mechanism, in concert with the excitatory effects of PGF_2α enables successful fertilization in the domestic bird.

Evaluation of the reproductive toxicity of naproxen sodium and meloxicam in male rats

Nonsteroidal anti-inflammatory drugs that are cyclooxygenase (COX) enzyme inhibitors have generally been used in short-term pain management and also to treat inflammation chronically. It is known that COX enzyme and prostaglandins play important roles in the regulation of reproductive functions in females. However, there are relatively few studies for the male reproductive system, and the results of these studies are contradictory. In this study, sperm count and motility, COX-1, COX-2, prostaglandin E1 (PGE1), prostaglandin E2 (PGE2), and prostaglandin F2α (PGF2α) levels in testis tissue, plasma follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone levels, and histopathological examination of testis tissue were evaluated after naproxen sodium and meloxicam administration in male rats. Also, testis superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), and glutathione (GSH) levels were measured to investigate the oxidation status. According to our results, sperm count and motility were significantly decreased in treatment groups. Plasma hormone levels did not show any statistical differences between the groups. COX-1, PGE2, and PGF2α levels were significantly decreased, while the decreases in COX-2 and PGE1 levels did not show any significance statistically. Testis SOD, catalase, GPx, and GSH levels were decreased significantly. According to the results of histopathological examination, damage in seminiferous tubules, where spermatogenesis developed, was observed. In conclusion, naproxen sodium and meloxicam decreased the sperm count and motility and also induced the damage of seminiferous tubules as a direct effect without affecting plasma hormone levels in our study. The mechanism of the reproductive toxicity induced by these agents may be based on the inhibition of prostaglandin synthesis and the induction of oxidative stress can be emphasized as a secondary factor.

Transport of organic cationic drugs: effect of ion-pair formation with bile salts on the biliary excretion and pharmacokinetics

More than 40% of clinically used drugs are organic cations (OCs), which are positively charged at a physiologic pH, and recent reports have established that these drugs are substrates of membrane transporters. The transport of OCs via membrane transporters may play important roles in gastrointestinal absorption, distribution to target sites, and biliary and/or renal elimination of various OC drugs. Almost 40 years ago, a molecular weight (Mw) threshold of 200 was reported to exist in rats for monoquaternary ammonium (mono QA) compounds to be substantially (e.g., >10% of iv dose) excreted to bile. It is well known that some OCs interact with appropriate endogenous organic anions in the body (e.g., bile salts) to form lipophilic ion-pair complexes. The ion-pair formation may influence the affinity or binding of OCs to membrane transporters that are relevant to biliary excretion. In that sense, the association of the ion-pair formation with the existence of the Mw threshold appears to be worthy of examination. It assumes the ion-pair formation of high Mw mono QA compounds (i.e., >200) in the presence of bile salts in the liver, followed by accelerated transport of the ion-pair complexes via relevant bile canalicular transporter(s). In this article, therefore, the transport of OC drugs will be reviewed with a special focus on the ion-pair formation hypothesis. Such information will deepen the understanding of the pharmacokinetics of OC drugs as well as the physiological roles of endogenous bile salts in the detoxification or phase II metabolism of high Mw QA drugs.

Effects of nimesulide on testicular functions in prepubertal albino rats

BACKGROUND

Daily consumption of painkillers has almost become a routine in many parts of Africa and Asia due to manual labor, especially in young adults. In view of the wide-scale use of painkillers in many parts of Africa and Asia, it is feared that the use of nimesulide may constitute an appreciable public health risk. The present work is aimed at assessing the long-term testicular toxicity of nimesulide in growing male albino rats.

METHODS

Male albino rats aged 4-5 weeks and weighing between 36 and 42 g were obtained from the Toxicology Unit of the Department of Pharmacology, Faculty of Pharmacy University of Nigeria, Nsukka, Nigeria. The animals were housed singly in a cross-ventilated room at a temperature 22°C±3°C and a 12-h light/12-h dark cycle. They were fed with standard rat pellets (Pfizer Pharmaceuticals, Ikeja, Nigeria) and were given water ad libitum. The rats were divided into three groups of five rats each: the first and second groups orally received 5 and 7.5 mg/kg/day of nimesulide, respectively, whereas the third group did not receive any drug and acted as controls for 56 days. Weekly body weight of each rat was taken. Blood samples were collected on the 56th day by cardiac puncture, and serum samples were frozen until analysis. Rats were sacrificed under ether anesthesia. Epididymal semen number was counted using a Neubauer counting chamber. Sperm motility was assayed microscopically within 5 min at 37°C. Estradiol and testosterone were analyzed with electrochemiluminescence immunoassay using Elecsys autoanalyzer, model 1010 (Roche, Mannheim, Germany). The testes were excised, weighed, and fixed in Bouin fluid and processed for histopathology.

RESULTS

Treatment with nimesulide did not significantly affect body weight, absolute and relative testis weights, or epididymal sperm number, but there were significant differences in testosterone and estradiol levels. At the doses studied, there were no significant changes in testicular architecture except for mild degenerative changes.

CONCLUSIONS

In conclusion, nimesulide at normal therapeutic doses may not be spermatoxic, but it is feared that at higher doses, it may have testicular toxicity in albino rats.

The irradiation of rabbit sperm cells with He-Ne laser prevents their in vitro liquid storage dependent damage

The aim of the study was to investigate the effects of different energy doses of helium-neon (He-Ne) laser irradiation on both mitochondrial bioenergetics functions and functional quality of rabbit spermatozoa during 48 h of in vitro liquid storage at 15 degrees C. 11 rabbit semen pools were each divided into four aliquots: three of them were irradiated with He-Ne laser with different energy doses (3.96, 6.12 and 9.00 J/cm(2)) being the last control kept under the same experimental conditions without irradiation. Sperm motility, viability and acrosome integrity were monitored together with cytochrome c oxidase (COX) activity and the cell energy charge (EC) at 0, 24 and 48 h of storage. Irradiated samples stored for 24 and 48 h better maintained motility (P < 0.01), acrosome integrity (P < 0.01) and viability (P < 0.05) with respect to the control, particularly with the energy dose of 6.12 J/cm(2) that showed the most intense biostimulative effect. COX activity and EC were immediately increased by irradiation particularly in the treatments 6.12 and 9.00 J/cm(2) (P < 0.05), that maintained their levels higher with respect to the control after 48 h of storage (P < 0.01). COX activity of rabbit sperm cells was positively correlated with EC (P < 0.05), viability (P < 0.01) and acrosome integrity (P < 0.05) parameters. These results indicate that the effects of He-Ne laser irradiation on sperm cells are mediated through the stimulation of the sperm mitochondrial respiratory chain and that this effect plays a significant role in the augmentation of the rabbit sperm cells' capability to survive during liquid storage conditions.

Evaluation of vaginal misoprostol effect on pregnancy rate after intrauterine insemination

The goal of this study was to evaluate the effect ofmisoprostol on pregnancy rate after intrauterine insemination. This randomized double blind clinical trial study was performed on 66 (33 cases and 33 controls) infertile women who referred to infertility center of Imam Khomeini Hospital Sari, Iran for intrauterine insemination during 2006-2007. The two groups were matched for age, infertility causes and BMI. After intrauterine insemination, 200 mcg misoprostol was placed in posterior fornix of case group and a similar placebo tablet in control group. Chemical and clinical pregnancies and complications were recorded. Results were analyzed by means of SPSS 11 software, paired t-test and student t-test. The p-values of less than 0.05 were considered to be statistically significant. Chemical pregnancy (positive BHCG) occurred in 6 patients (18.2%) in each group. Clinical pregnancy occurred in 5 patients (15.15%) in case and 6 patients (18.2%) in controls. There were no significant statistical differences in complications between the two groups. Vaginal misoprostol after intrauterine insemination does not improve pregnancy rate.

VEGF expression and the effect of NSAIDs on ascites cell proliferation in the hen model of ovarian cancer

OBJECTIVES

We aimed to determine the expression of vascular endothelial growth factor (VEGF) and the effect of nonsteroidal anti-inflammatory drugs (NSAIDs) on the proliferation of cells isolated from ascites in the hen model of ovarian cancer.

METHODS

Ovarian tumor and normal ovary were collected from hens and ascites cells were isolated from hens with ovarian cancer. Quantitative real-time PCR was used to quantify mRNA expression. Immunohistochemical and/or Western blot analyses were used to localize protein expression in ovarian tumors, normal ovaries, and ascites cells. Cells were treated with a nonspecific, COX-1-specific, or COX-2-specific NSAID and proliferation was determined.

RESULTS

VEGF mRNA was increased in ascites cells and there was a trend for a correlation between VEGF mRNA in ascites cells and ascites volume. VEGF protein was localized to theca cells of normal ovaries, in glandular areas of tumors, and to the cytoplasm of ascites cells. Aspirin and a COX-1-specific inhibitor decreased the proliferation of ascites cells, whereas a COX-2-specific inhibitor did not.

CONCLUSIONS

VEGF may play a role in ovarian cancer progression in the hen and the proliferation of ascites cells can be decreased by targeting the COX-1 but not COX-2 pathway.

Free radicals and antioxidants in inflammatory processes and ischemia-reperfusion injury

This article discusses the current understanding of the role of free radicals and antioxidants in inflammatory processes and in ischemia reperfusion injury. It begins by describing the manifestations of acute inflammation and outlining the cellular events that occur during inflammation. It then describes the biochemical mediators of inflammation with special attention to nitric oxide. It details the process of hypoxia reperfusion injury, the enzymes involved, its treatment, and studies involving specific hypoxia reperfusion injuries in various animal species.

Localization of cyclooxygenase-2 in mice testis and assessment of its possible role through suppressing its expression using nimesulide: a preferential cyclooxygenase-2 inhibitor

Present generation non-steroidal anti-inflammatory drugs (NSAID) are potent inhibitors of the enzyme cyclooxygenase-2 (COX-2). Even though they exhibit reduced incidence of gastrotoxicity, severe nephrotoxicity and other side effects have been widely reported with respect to usage of these drugs. Since COX-2 levels are not only upregulated by inflammation but also by other stimuli such as cytokines, growth factors, mitogens and steroid hormones, we investigated the localization of COX-2 and activity of both COX-1 and COX-2 in mice testis. To correlate the localization of COX-2 with its function we suppressed COX-2 expression with the aid of nimesulide a preferential COX-2 inhibitor. We found COX-2 was constitutively expressed in the Leydig cells of mice testis suggesting a role on testosterone synthesis. Suppression of COX-2 resulted in increased concentration of most of polyunsaturated fatty acids especially arachidonic acid (AA). Prostaglandin (PG) levels which showed an initial decline during nimesulide treatment had a reversible effect during prolonged treatment. These findings state that cyclooxygenase is constitutively expressed in mice testis and continuous inhibition of COX-2 interferes in maturation of sperm.