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

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.

New developments of the effect of melatonin on reproduction

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.

Descriptive histomorphological evaluation of the testis and caudal epididymis following treatment with rooibos(Aspalathus linearis),honeybush(Cyclopia intermedia)and sutherlandia(Lessertia frutescens)in healthy and streptozotocin-induced diabetic rats

Objective:To evaluate the testis and the cauda epididymis after treating both healthy and diabetic rats with rooibos(Aspalathus linearis),honeybush(Cyclopia intermedia),and sutherlandia(Lessertia frutescens),respectively.Methods:Ninety male Wistar rats were randomly divided into nine groups(n=10 per group).Fifty rats were randomized to receive tap water,0.1 M citrate buffer,2.0%fermented rooibos,4.0%fermented honeybush,or 0.2%unfermented sutherlandia.Diabetes was induced via a single intraperitoneal injection of streptozotocin(STZ)at 45 mg/kg in 40 rats.The diabetic rats were randomized to receive tap water,2.0%fermented rooibos,4.0%fermented honeybush,or 0.2%unfermented sutherlandia.Rats were sacrificed after seven weeks of diabetic induction.Blood was collected for hormonal assay,while the testes and caudal epididymis were retrieved for histomorphological evaluations.Results:Diabetic rats treated with 2.0%fermented rooibos exhibited a significant increase in fasting plasma glucose(FPG)versus the vehicle group(P=0.002),and a 3.6%decrease compared to the diabetic control group(P>0.05).Diabetic rats treated with honeybush or sutherlandia showed 23.6%and 15.4%decrease in FPG when compared to the diabetic control group,respectively(both P>0.05).The diabetic control rats had a significant decrease in the percentage of histologically normal seminiferous tubules compared to the control group(P=0.049).There was 21.0%,14.0%,and 5.4%rise in the percentage of normal seminiferous tubules in diabetic rats receiving rooibos,honeybush or sutherlandia,respectively,compared to the diabetic control group.The infusion control groups(rooibos,honeybush and sutherlandia)showed normal seminiferous tubules,presence of spermatozoa in the epididymal lumen,and had normal overall architecture.Both testicular and epididymal morphology were altered in the diabetic control group,but these disruptions were mildly ameliorated by rooibos,honeybush,and sutherlandia.Conclusions:The detrimental effects of diabetes on the histomorphological architecture of the testis and epididymis are mildly ameliorated by the infusions(2.0%fermented rooibos,4.0%fermented honeybush,and 0.2%unfermented sutherlandia).

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

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.

Obesity： modern man＇s fertility nemesis

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.

Diabetes mellitus and male infertility

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.

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

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)infusions.Methods: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%sutherlandia.Rats were sacrificed 7 weeks after induction of diabetes mellitus.The testes and epididymides were harvested and weighed after induction.Spermatozoa were retrieved from the cauda epididymis for motility,concentration,and morphology analysis,and the testis was used for all biochemical assays.Oxidative stress was determined by measuring malondialdehyde levels,catalase,and superoxide dismutase activities,while apoptotic biomarkers were evaluated by Western blotting assays.Results: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(P<0.001).Rats in the diabetic control group had a reduction 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 group.The 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 groups.In addition,the percentage of morphologically normal spermatozoa was increased by 13.0%,16.0%,and 15.0%after treatment with rooibos,honeybush,and sutherlandia,respectively and the rats in the diabetic+infusion groups also displayed an increase in superoxide dismutase activity when compared to the diabetic control group.Conclusions:Rooibos,honeybush and sutherlandia infusions may partly alleviate diabetes-induced sperm function impairment by reducing oxidative stress.

氧化磷酸化与糖酵解：精子以何种途径获取能量？

精子为高度特异性的细胞，提供精子重要功能的主要能源一一三磷酸腺苷（ATP）主要通过两种代谢途径形成，即糖酵解和氧化磷酸化（OXPHOS）。ATP除了在精子的头部和鞭毛的主段通过糖酵解的方式产生外，在线粒体主要通过OXPHOS的方式产生。然而，在精子成功受精的过程中主要以何种方式产生ATP具有很大的差异性。与糖酵解相比，线粒体呼吸被认为是一种更有效的ATP合成代谢过程。然而，研究表明ATP从线粒体到精子鞭毛末端的扩散电位不足以支持精子的运动，这表明糖酵解是精子尾部区域主要的获能方式。多项研究表明虽然糖酵解是鞭毛产生ATP的主要方式，但是，精子运动所需要的能量主要还是来自于线粒体的呼吸。有些研究表明当糖酵解受到抑制的时候，精子仍能维持其正常的运动和功能，虽然目前尚未明确这种运动是否能持续足够长的时间，是否能够达到有效受精。本文主要目的是对哺乳动物精子能量的代谢进行综述，分析人类精子在受精的过程中以何种ATP代谢途径作为主要的能量供应方式。