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Insulin and leptin enhance human sperm motility, acrosome reaction and nitric oxide production

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Asian Journal of Andrology 2008年第5期10卷 799-807页

作者： Fanuel Lampiao Stefan S. du plessis Division of Medical Physiology Department of Biomedical Sciences University of Stellenbosch Tygerberg 7505 South Africa

Aim： To investigate the in vitro effects of insulin and leptin on human sperm motility, viability, acrosome reaction and nitric oxide （NO） production. Methods： Washed human spermatozoa from normozoospermic donors were treated with insulin （10 μIU） and leptin （10 nmol）. Insulin and leptin effects were blocked by inhibition of their intracellular effector, phosphotidylinositol 3-kinase （PI3K）, by wortmannin （10 μmol） 30 min prior to insulin and leptin being given. Computer-assisted semen analysis was used to assess motility after 1, 2 and 3 h of incubation. Viability was assessed by fluorescence-activated cell sorting using propidium iodide as a fluorescent probe. Acrosome-reacted cells were observed under a fluorescent microscope using fluorescein-isothiocyanate-Pisum sativum agglutinin as a probe. NO was measured after treating the sperm with 4,5-diaminofluorescein-2/diacetate （DAF-2/DA） and analyzed by fluorescence-activated cell sorting. Results： Insulin and leptin significantly increased total motility, progressive motility and acrosome reaction, as well as NO production. Conclusion： This study showed the in vitro beneficial effects of insulin and leptin on human sperm function. These hormones could play a role in enhancing the fertilization capacity of human spermatozoa.

关键词： insulin leptin spermatozoa nitric oxide motility acrosome reaction

Obesity： modern man＇s fertility nemesis

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Asian Journal of Andrology 2010年第4期12卷 480-489页

作者： Stephanie Cabler Ashok Agarwal Margot Flint Stefan S. du plessis Center for Reproductive Medicine The Cleveland Clinic 9500 Euclid Avenue Cleveland OH 44195 USA Division of Medical Physiology Faculty of Health Sciences Stellenbosch University PO Box 19063 Tygerberg 7505 South Africa

The obesity pandemic has grown to concerning proportions in recent years, not only in the Western World, but in developing countries as well. The corresponding decrease in male fertility and fecundity may be explained in parallel to obesity, and obesity should be considered as an etiology of male fertility. Studies show that obesity contributes to infertility by reducing semen quality, changing sperm proteomes, contributing to erectile dysfunction, and inducing other physical problems related to obesity. Mechanisms for explaining the effect of obesity on male infertility include abnormal reproductive hormone levels, an increased release of adipose-derived hormones and adipokines associated with obesity, and other physical problems including sleep apnea and increased scrotal temperatures. Recently, genetic factors and markers for an obesity-related infertility have been discovered and may explain the difference between fertile obese and infertile obese men. Treatments are available for not only infertility related to obesity, but also as a treatment for the other comorbidities arising from obesity. Natural weight loss, as well as bariatric surgery are options for obese patients and have shown promising results in restoring fertility and normal hormonal profiles. Therapeutic interventions including aromatase inhibitors, exogenous testosterone replacement therapy and maintenance and regulation of adipose-derived hormones, particularly leptin, may also be able to restore fertility in obese males. Because of the relative unawareness and lack of research in this area, controlled studies should be undertaken and more focus should be given to obesity as an etiolgy of male infertility.

关键词： adipokines infertility leptin obesity spermatozoa

Diabetes mellitus and male infertility

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Asian pacific Journal of Reproduction 2018年第1期7卷 6-14页

作者： Omolaoye Temidayo S du plessis Stefan S Division of Medical Physiology Faculty of Medicine and Health SciencesStellenbosch UniversityTygerbergSouth Africa

Infertility is prevalent in about 10%-25% of couples in their reproductive age, analogous to 60-80 million infertile couples globally. Of these infertility cases, 10%-30% are exclusively attributed to a problem of the male. Several diseases have been implicated as contributors to deteriorating male fertility and diabetes mellitus (DM) is included. DM, a chronic non-communicable disease, has been considered as one of the most appreciable health threats, as it affects 9% (422 million) of the world's population as of 2014. It is characterised by hyperglycaemia, which can result from the inability of the pancreaticβ-cells to secrete insulin or from the target tissue becoming insensitive to insulin. DM has been reported to influence male reproductive function through diverse pathways and mechanisms. The adverse effects of reactive oxygen species and successive development of oxidative stress that occur due to DM have been investigated and implicated by several studies. The products of non-enzymatic glycosylation are reported to be widely distributed in the reproductive tract of diabetic men. Additionally, DM has been implicated to impair the processes of male sexual acts. Data reported in this review were extracted from PubMed, Google Scholar, Science Direct and Scopus with diabetes and male infertility as the key search words. In light of the aforementioned, the aim of this review is to provide brief background information on DM as well highlight and explain the likely mechanisms of male fertility which DM impacts.

关键词： Diabetes mellitus Male infertility Diabetic neuropathy Oxidative stress Reactive oxygen species Advanced glycated end products

Active explosion barrier performance against methane and coal dust explosions

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International Journal of Coal Science & Technology 2015年第4期2卷 261-268页

作者： J. J. L. du plessis Department of Mining Engineering University of PretoriaPretoria 0028 South Africa

Preventing the propagation of methane or coal dust explosions through the use of active explosion-suppression systems remains one of the most underutilised explosion controls in underground coal mines. As part of the effort to develop better technologies to safeguard mines, the use of active barrier systems was investigated at Kloppersbos in South Africa. The system is designed to meet the requirements of the European Standard （EN 14591-4 2007） as well as the Mine Safety Standardisation in the Ministry of Coal Industry, Coal Industrial 1 Standard of the Peoples Republic of China （MT 694-1997）. From the tests conducted, it can be concluded that the ExploSpot System was successful in stopping flame propagation for both methane and methane and coal dust hybrid explosions when ammonium phosphate powder was used as the suppression material. The use of this barrier will provide coal mine management with an additional explosion control close to the point of ignition and may find application within longwall faces further protecting mines against the risk of an explosion propagating throughout a mine.

关键词： Coal Methane Explosions Active barriers

Testicular oxidative stress and apoptosis status in streptozotocin-induced diabetic rats after treatment with rooibos(Aspalathus linearis),honeybush(Cyclopia intermedia),and sutherlandia(Lessertia frutescens)infusions

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Asian pacific Journal of Reproduction 2021年第1期10卷 11-20页

作者： Temidayo S.Omolaoye Shantal Windvogel Stefan S.du plessis Division of Medical Physiology Faculty of Medicine and Health SciencesStellenbosch UniversityTygerbergSouth Africa Department of Basic Sciences College of MedicineMohammed Bin Rashid University of Medicine and Health SciencesDubaiUnited Arab Emirates Centre for Cardio-metabolic Research in Africa Stellenbosch UniversitySouth Africa

Objective:To investigate the testicular oxidative stress and apoptosis status,as well as the sperm functional parameters in streptozotocin(STZ)induced diabetic rats following treatment with rooibos(Aspalathus linearis),honeybush(Cyclopia intermedia)and sutherlandia(Lessertia frutescens)***:Diabetes was induced by injecting fourteen-week-old adult male Wistar rats(250-300 g)with a single intraperitoneal injection of STZ(45 mg/kg body weight).Fifty rats were randomly divided into five groups:the vehicle group received 0.1 M citrate buffer,the diabetic control group received 45 mg/kg STZ,the diabetic+rooibos group received 45 mg/kg STZ+2.0%rooibos,the diabetic+honeybush group received 45 mg/kg STZ+4.0%honeybush,and the diabetic+sutherlandia group received 45 mg/kg STZ+0.2%*** were sacrificed 7 weeks after induction of diabetes *** testes and epididymides were harvested and weighed after *** were retrieved from the cauda epididymis for motility,concentration,and morphology analysis,and the testis was used for all biochemical *** stress was determined by measuring malondialdehyde levels,catalase,and superoxide dismutase activities,while apoptotic biomarkers were evaluated by Western blotting ***:After induction of diabetes,rats in the diabetic control group,diabetic+rooibos group,diabetic+honeybush group,and diabetic+sutherlandia group presented with significantly elevated blood glucose levels as compared with the vehicle group(Pduction in sperm progressive motility,while rats in the diabetic+rooibos group and the diabetic+sutherlandia group displayed an increase in progressive motility as compared with the diabetic control *** diabetic control animals showed a 40.0%decrease in sperm concentration when compared to the vehicle group,and there were no significant differences in sperm kinematic and speed parameters between the *** add

关键词： Diabetes Sperm Oxidative stress Apoptosis Rooibos Honeybush Sutherlandia

Prototype Line Crawler for Power Line Inspection

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Journal of Energy and Power Engineering 2013年第11期7卷 2174-2180页

作者： Rupert Gouws Nicolaas du plessis Faculty of Engineering North-West University Potchefstroom 2531 South Africa

In South Africa, electricity is supplied through thousands-of-kilometers of overhead power cables, which is owned by Eskom the national energy supplier. Currently monitoring of these overhead power cables are done by means of helicopter inspection flights and foot patrols, which are infrequent and expensive. In this paper, the authors present the design of a prototype power line crawler （inspection robot） for the monitoring of these overhead power lines in South Africa. The designed prototype power line crawler is capable of driving on the wire, balancing on the wire and is capable of maneuvering past certain obstacles found on the overhead power cables. The prototype power line crawler is designed to host a monitoring system that monitors the power line as the inspection robot drives on it. Various experimental tests were performed and are presented in this paper, showing the capability of performing these tasks. This prototype inspection robot ensures a platform for future development in this area.

关键词： Inspection robot line crawler power lines maneuverabiliW center of ~ravitv balancing.

3xidative phosphorylation versus glycolysis： what Fuel do spermatozoa use？

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Asian Journal of Andrology 2015年第2期17卷 230-235,I0007,I0008页

作者： Stefan S du plessis Ashok Agarwal Gayatri Mohanty Michelle van der Linde Division of Medical Physiology Department of Biomedical Sciences Faculty of Medicine and Health Sciences Stellenbosch University Tygerberg South Africa Center for Reproductive Medicine Cleveland Clinic Cleveland Ohio USA Department of Zoology Ravenshaw University Cuttack Odisha India

Spermatozoa are highly specialized cells. Adenosine triphosphate （ATP）, which provides the energy for supporting the key functions of the spermatozoa, is formed by 2 metabolic pathways, namely glycolysis and oxidative phosphorylation （OXPHOS）. It is produced in the mitochondria through OXPHOS as well as in the head and principal piece of the flagellum through glycolysis. However, there is a great discrepancy as to which method of ATP production is primarily utilized by the spermatozoa for successful fertilization. Mitochondrial respiration is considered to be a more efficient metabolic process for ATP synthesis in comparison to glycolysis. However, studies have shown that the diffusion potential of ATP from the mitochondria to the distal end of the flagellum is not sufficient to support sperm motility, suggesting that glycolysis in the tail region is the preferred pathway for energy production. It is suggested by many investigators that although glycolysis forms the major source of ATP along the flagellum, energy required for sperm motility is mainly produced during mitochondrial respiration. Nevertheless, some studies have shown that when glycolysis is inhibited, proper functioning and motility of spermatozoa remains intact although it is unclear whether such motility can be sustained for prolonged periods of time, or is sufficiently vigorous to achieve optimal fertilization. The purpose of this article is to provide an overview of mammalian sperm energy metabolism and identify the preferred metabolic pathway for ATP generation which forms the basis of energy Droduction in human spermatozoa during fertilization.

关键词： adenosine triphosphate energy glycolysis oxidative phosphorylation spermatozoa

New developments of the effect of melatonin on reproduction

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World Journal of Obstetrics and Gynecology 2013年第2期2卷 8-15页

作者： Fanuel Lampiao Stefan S du plessis Division of Physiology Department of Basic Medical SciencesCollege of MedicineBlantyre 3Malawi Division of Medical Physiology Stellenbosch UniversityTygerberg CampusTygerberg 19063South Africa

In the past decades, a lot of advances in understanding the biochemistry and physiology of the pineal gland have been made. There is evidence that it interacts with many endocrine as well as non-endocrine tissues to influence their metabolic activity modulating many organs and functions. Melatonin is secreted by the pineal gland in the brain and plays an important role in regulating the neuroendocrine system. This hormone is one of the major role players in the regulation of the circadian sleep-wake cycle. It is normally released from the pineal gland during the night in response to environmental changes in light. Studies have shown that melatonin plays a role in the regulation of many reproductive processes such as puberty, gonadal function, and pregnancy. Beside these, melatonin has been shown to be able to directly neutralize a number of free radicals and reactive oxygen and nitrogen species. The main objective of this review is to provide comprehensive information about the new developments in melatonin research regarding its role in reproduction. A review of international scientific literature was done and a question-and-answer format was used in an attempt to convey comprehensive information in a simple manner. This review discusses evidence currently available relating to the effect of melatonin on reproductive processes. It deliberates the mechanism of action of melatonin, its effect on puberty, testicular and ovafunction, pregnancy, and oxidative stress. A growing body of scientific evidence is suggesting that melatonin plays an important role in reproductive function. It is therefore imperative to highlight the beneficial effects of this hormone in improving the reproductive processes.

关键词： Melatonin Reproduction Reactive oxygen species Antioxidants Pineal gland

The in vitro effects of superoxide, some commercially available antioxidants and red palm oil on sperm motility

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Asian Journal of Andrology 2009年第6期11卷 695-702页

作者： Yapo Guillaume Aboua Stefan Stephanus du plessis Patricia Reichgelt Nicole Brooks Department of Biomedical Sciences Faculty of Health and Wellness Sciences Cape Peninsula University of TechnologyBellville 7535 South Africa Division of Medical Physiology Faculty of Health Sciences Stellenbosch University Tygerberg 7505 South Africa

In this study, two commercially available superoxide scavengers, tetrakis （1-methyl-4-pyridyl） porphyrin （Mn[III]TMPyP） and superoxide dismutase （SOD）, as well as red palm oil （RPO）, a natural vegetable oil, had been used to investigate their possible in vitro effects against the toxic effects of superoxide （O2＋） on human sperm motility. Semen samples were obtained from 12 normozoospermic healthy volunteer donors aged between 19 and 23 years. The O2＋donor 2,3-dimetoxyl-l,4-naphthoquinone （DMNQ）（2.5 μmol· L^-1-100 μmol· L^-1） was added to normozoospermic post-swim-up sperm in the presence or absence of Mn（III）TMPyP （50 μmol· L^-1）, SOD （50 IU） or RPO （0.1% or 0.5%）. Computer-assisted semen analysis was used to analyze various motility parameters. The parameters of interest were percentage of motile cells, progressive motility, rapid cells and static cells. Concentrations of higher than 25 μmol· L^-1 DMNQ were detrimental to sperm motility. Mn（III）TMPyP was able to attenuate the effect of O2＋ on the motility parameters. In vitro addition of SOD and RPO showed harmful effects on sperm motility.

关键词： antioxidants motility red palm oil superoxide