Metformin Improves Fertility in Obese Males by Alleviating Oxidative Stress-Induced Blood-Testis Barrier Damage

Signatures of metabolic diseases on spermatogenesis and testicular metabolism

Diets leading to caloric overload are linked to metabolic disorders and reproductive function impairment. Metabolic and hormonal abnormalities stand out as defining features of metabolic disorders, and substantially affect the functionality of the testis. Metabolic disorders induce testicular metabolic dysfunction, chronic inflammation and oxidative stress. The disruption of gastrointestinal, pancreatic, adipose tissue and testicular hormonal regulation induced by metabolic disorders can also contribute to a state of compromised fertility. In this Review, we will delve into the effects of high-fat diets and metabolic disorders on testicular metabolism and spermatogenesis, which are crucial elements for male reproductive function. Moreover, metabolic disorders have been shown to influence the epigenome of male gametes and might have a potential role in transmitting phenotype traits across generations. However, the existing evidence strongly underscores the unmet need to understand the mechanisms responsible for transgenerational paternal inheritance of male reproductive function impairment related to metabolic disorders. This knowledge could be useful for developing targeted interventions to prevent, counteract, and most of all break the perpetuation chain of male reproductive dysfunction associated with metabolic disorders across generations.

1-DNJ Alleviates Obesity-Induced Testicular Inflammation in Mice Model by Inhibiting IKKβ/ NF-kB Pathway

Obesity is associated with chronic inflammation that affects various organs in the body, including the reproductive system, which is a key factor in male infertility. 1-Deoxynojirimycin (1-DNJ) is a natural alkaloid in mulberry leaves, which has anti-inflammatory capabilities, yet, it's effects on obesity-induced inflammation-related male infertility remain unclear. Therefore, this research investigates the underlying mechanism by which 1-DNJ may mitigate fertility impairment in male mice caused by obesity-related inflammation. Male mice with high-fat diet (HFD)-induced obesity were treated with 1-DNJ or metformin for 8 weeks. Metabolic profiles were evaluated by enzyme method. Reproductive capacity was assessed by sperm viability, motility and counts, immunohistochemistry was performed to evaluate the testicular damage caused by obesity and inflammation. The inflammation was assessed by measuring the levels of tumor necrosis factor α (TNFα), interleukin 1β (IL-1β), and interleukin 6 (IL-6). The activation of IκB kinase β (IKKβ) and nuclear factor κB (NF-κB) was examined using western blot and immunohistochemistry. HFD induced obesity in mice with obvious lipid metabolism disorder. The obese male mice had a decreased testosterone level, impaired sperm motility, and increased inflammatory factors. 1-DNJ treatment improved the testosterone level in the obese mice, ameliorated the testicular structure damage and improve sperm viability. In addition, 1-DNJ treatment inhibited IKKβ/NF-kB signaling pathway and reduced inflammation in obese mice. 1-DNJ can improve the fertility of obese men by reducing obesity as well as obesity-induced inflammation. These findings provide new insights for 1-DNJ to alleviate inflammation caused by obesity and provide future possibilities for treating male infertility.

Paternal Use of Metformin During the Sperm Development Period Preceding Conception and Risk for Major Congenital Malformations in Newborns

BACKGROUND

Metformin is the most used oral antidiabetic medication. Despite its established safety profile, it has known antiandrogenic and epigenetic modifying effects. This raised concerns about possible adverse developmental effects caused by genomic alterations related to paternal use of metformin during the spermatogenesis period preceding conception.

OBJECTIVE

To assess the potential adverse intergenerational effect of metformin by examining the association between paternal metformin use during spermatogenesis and major congenital malformations (MCMs) in newborns.

DESIGN

Nationally representative cohort study.

SETTING

A large Israeli health fund.

PARTICIPANTS

383 851 live births linked to fathers and mothers that occurred in 1999 to 2020.

MEASUREMENTS

MCMs and parental cardiometabolic conditions were ascertained using clinical diagnoses, medication dispensing information, and laboratory test results. The effect of metformin use on MCMs was estimated using general estimating equations, accounting for concurrent use of other antidiabetic medications and parental cardiometabolic morbidity.

RESULTS

Compared with unexposed fathers, the prevalence of cardiometabolic morbidity was substantially higher among fathers who used metformin during spermatogenesis, and their spouses. Whereas the crude odds ratio (OR) for paternal metformin exposure in all formulations and MCMs was 1.28 (95% CI, 1.01 to 1.64), the adjusted OR was 1.00 (CI, 0.76 to 1.31). Within specific treatment regimens, the adjusted OR was 0.86 (CI, 0.60 to 1.23) for metformin in monotherapy and 1.36 (CI, 1.00 to 1.85) for metformin in polytherapy, a treatment that was more common in patients with more poorly controlled diabetes.

LIMITATION

Laboratory test results for hemoglobin A1c to assess underlying diabetes severity were available only for a subset of the cohort.

CONCLUSION

Paternal use of metformin in monotherapy does not increase the risk for MCMs. Association for metformin in polytherapy could potentially be explained by worse underlying parental cardiometabolic risk profile.

PRIMARY FUNDING SOURCE

None.

The effects of fine particulate matter on the blood-testis barrier and its potential mechanisms

With the rapid expansion of industrial scale, an increasing number of fine particulate matter (PM2.5) has bringing health concerns. Although exposure to PM2.5 has been clearly associated with male reproductive toxicity, the exact mechanisms are still unclear. Recent studies demonstrated that exposure to PM2.5 can disturb spermatogenesis through destroying the blood-testis barrier (BTB), consisting of different junction types, containing tight junctions (TJs), gap junctions (GJs), ectoplasmic specialization (ES) and desmosomes. The BTB is one of the tightest blood-tissue barriers among mammals, which isolating germ cells from hazardous substances and immune cell infiltration during spermatogenesis. Therefore, once the BTB is destroyed, hazardous substances and immune cells will enter seminiferous tubule and cause adversely reproductive effects. In addition, PM2.5 also has shown to cause cells and tissues injury via inducing autophagy, inflammation, sex hormones disorder, and oxidative stress. However, the exact mechanisms of the disruption of the BTB, induced by PM2.5, are still unclear. It is suggested that more research is required to identify the potential mechanisms. In this review, we aim to understand the adverse effects on the BTB after exposure to PM2.5 and explore its potential mechanisms, which provides novel insight into accounting for PM2.5-induced BTB injury.

Effect of Metformin on Sertoli Cell Fatty Acid Metabolism and Blood-Testis Barrier Formation

Sertoli cells (SCs) are essential to maintaining germ cell development. Metformin, the main pharmacologic treatment for pediatric type 2 diabetes, is administered to children during SC maturation. The present study aimed to analyze whether metformin affects SC energy metabolism and blood-testis barrier (BTB) integrity. Primary SC cultures were used for the in vitro studies. In vivo effects were studied in Sprague-Dawley rats treated with 200 mg/kg metformin from Pnd14 to Pnd30. Metformin decreased fatty acid oxidation and increased 3-hydroxybutyrate production in vitro. Moreover, it decreased the transepithelial electrical resistance across the monolayer and induced ZO-1 redistribution, suggesting an alteration of cell junctions. In vivo, a mild but significant increase in BTB permeability and ZO-1 expression was observed in the metformin group, without changes in testicular histology and meiosis progression. Additionally, adult rats that received metformin treatment during the juvenile period showed no alteration in BTB permeability or daily sperm production. In conclusion, metformin exposure may affect BTB permeability in juvenile rats, but this seems not to influence spermatogenesis progression. Considering the results obtained in adult animals, it is possible to speculate that metformin treatment during the juvenile period does not affect testicular function in adulthood.

Ameliorative effects of Myrtus communis L. extract involving the inhibition of oxidative stress on high fat diet-induced testis damage in rats

The possible protective effects of Myrtus communis L. (MC) extract on a high fat diet (HFD)-induced testicular injury in a rat model were investigated using histological and biochemical methods. Wistar albino rats were divided into three groups: a standard diet control group; a HFD group; and an HFD+MC group. The HFD and HFD+MC groups were fed with a HFD for 16 weeks. MC extract (100 mg/kg) was given orally five days a week to the rats in the HFD+MC group during the last four weeks of the experiment. Leptin, triglyceride, high-density lipoproteins, cholesterol, estrogen, testosterone, LH and FSH were analyzed in blood serum. Sperm parameters were evaluated from the epididymis. Testicular morphology, proliferative, apoptotic and NADPH oxidase-2 (NOX2)-positive cells were evaluated histologically. Testicular oxidative stress parameters were analyzed biochemically. In the HFD group, lipid and hormone profiles were changed, abnormal spermatozoa, degenerated seminiferous tubules with apoptotic and NOX2-positive cells were increased in number, and sperm motility and germinal proliferative cells decreased compared to the control group. Moreover, testicular malondialdehyde, 8-hydroxy-2-deoxyguanosine and myeloperoxidase levels increased, whereas glutathione and superoxide dismutase levels decreased in the HFD group compared to the control group. All these histological and biochemical features were ameliorated by MC treatment of HFD-fed rats. In conclusion, HFD caused alterations in sperm parameters and testicular morphology by increasing oxidative damage and apoptosis. MC extract may have potential protective effects by inhibiting oxidative damage.

Infertility Improvement after Medical Weight Loss in Women and Men: A Review of the Literature

Infertility is a modern health problem. Obesity is another expanding health issue associated with chronic diseases among which infertility is also included. This review will focus on the effects of weight loss by medical therapy on fertility regarding reproductive hormonal profile, ovulation rates, time to pregnancy, implantation rates, pregnancy rates, normal embryo development, and live birth rates. We comprised medicine already used for weight loss, such as orlistat and metformin, and emerging medical treatments, such as Glucagon-Like Peptide-1 receptor agonists (GLP-1 RA). Their use is not recommended during a planned pregnancy, and they should be discontinued in such cases. The main outcomes of this literature review are the following: modest weight loss after medication and the duration of the treatment are important factors for fertility improvement. The fecundity outcomes upon which medical-induced weight loss provides significant results are the female reproductive hormonal profile, menstrual cyclicity, ovulation and conception rates, and pregnancy rates. Regarding the male reproductive system, the fertility outcomes that feature significant alterations after medically induced weight loss are as follows: the male reproductive hormonal profile, sperm motility, movement and morphology, weight of reproductive organs, and sexual function. The newer promising GLP-1 RAs show expectations regarding fertility improvement, as they have evidenced encouraging effects on improving ovulation rates and regulating the menstrual cycle. However, more human studies are needed to confirm this. Future research should aim to provide answers about whether medical weight loss therapies affect fertility indirectly through weight loss or by a possible direct action on the reproductive system.

Recovering Spermatogenesis By Protected Cryopreservation Using Metformin and Transplanting Spermatogonial Stem Cells Into Testis in an Azoospermia Mouse Model

Cryopreservation and transplantation of spermatogonial stem cells (SSCs) may serve as a new method to restore male fertility in patients undergoing chemotherapy or radiotherapy. However, SSCs may be damaged during cryopreservation due to the production of reactive oxygen species (ROS). Therefore, different antioxidants have been used as protective agents. Studies have shown that metformin (MET) has antioxidant activity. The aim of this study was to assess the antioxidant and antiapoptotic effects of MET in frozen-thawed SSCs. In addition, the effect of MET on the proliferation and differentiation of SSCs was evaluated. To this end, SSCs were isolated from mouse pups aged 3-6 days old, cultured, identified by flow cytometry (ID4, INTEGRIN β1+), and finally evaluated for survival and ROS rate. SSCs were transplanted after busulfan and cadmium treatment. Cryopreserved SSCs with and without MET were transplanted after 1 month of cryopreservation. Eight weeks after transplantation, the recipient testes were evaluated for the expression of apoptosis (BAX, BCL2), proliferation (PLZF), and differentiation (SCP3, TP1, TP2, PRM1) markers using immunohistochemistry, Western blot, and quantitative real-time polymerase chain reaction. The findings revealed that the survival rate of SSCs was higher in the 500 μm/mL MET group compared to the other groups (50 and 5000 μm/mL). MET significantly decreased the intracellular ROS production. Transplantation of SSCs increased the expression level of proliferation (PLZF) and differentiation (SCP3, TP1, TP2, PRM1) markers compared to azoospermia group, and their levels were significantly higher in the MET group compared to the cryopreservation group containing basic freezing medium (p < 0.05). MET increased the survival rate of SSCs, proliferation, and differentiation and decreased the ROS production and the apoptosis rate. Cryopreservation by MET seems to be effective in treating infertility.

Extensive therapeutic effects, underlying molecular mechanisms and disease treatment prediction of Metformin: a systematic review

Metformin (Met), a first-line management for type 2 diabetes mellitus, has been expansively employed and studied with results indicating its therapeutic potential extending beyond glycemic control. Beyond its established role, this therapeutic drug demonstrates a broad spectrum of action encompassing over 60 disorders, encompassing metabolic conditions, inflammatory disorders, carcinomas, cardiovascular diseases, and cerebrovascular pathologies. There is clear evidence of Met's action targeting specific nodes in the molecular pathways of these diseases and, intriguingly, interactions with the intestinal microbiota and epigenetic processes have been explored. Furthermore, novel Met derivatives with structural modifications tailored to diverse diseases have been synthesized and assessed. This manuscript proffers a comprehensive thematic review of the diseases amenable to Met treatment, elucidates their molecular mechanisms, and employs informatics technology to prospect future therapeutic applications of Met. These data and insights gleaned considerably contribute to enriching our understanding and appreciation of Met's far-reaching clinical potential and therapeutic applicability.

Polystyrene nanoplastics aggravate reproductive system damage in obese male mice by perturbation of the testis redox homeostasis

The potential impact of the combination of a high-fat diet (HFD) and polystyrene nanoplastics (PS-NPs) on fertility cannot be ignored, especially when the fertility rate is declining. However, it has not attracted considerable attention. In this study, an obese mouse model was established using an HFD, and the reproductive function of male mice was evaluated after intragastric administration of 100 μL of a 10 mg/mL PS-NP suspension for 4 weeks. By determining the morphology and vitality of sperm and related indicators of testosterone production, it was found that PS-NPs aggravated the destruction of sperm mitochondrial structure, decrease sperm activity, and testosterone production in HFD-fed mice. To comprehensively analyze the injury mechanism, the integrity of the blood testicular barrier (BTB) and the function of Leydig and Sertoli cells were further analyzed. It was found that PS-NPs could destroy BTB, promote the degeneration of Leydig cells, reduce the number of Sertoli cells, and decrease lactate secretion in HFD-fed mice. PS-NPs further interfered with redox homeostasis in the testicular tissues of HFD-fed mice. This study found that PS-NPs could aggravate the damage to the reproductive system of obese male mice by further perturbing its redox homeostasis and revealed the potential health risk of PS-NPs exposure under an HFD.

Rutin ameliorates perfluorooctanoic acid-induced testicular injury in mice by reducing oxidative stress and improving lipid metabolism

This study investigated the protective effect of rutin on reproductive and blood-testis barrier (BTB) damage induced by perfluorooctanoic acid (PFOA) exposure. In this study, male ICR mice were randomly divided into three groups, Ctrl group (ddH2O, 5 mL/kg), PFOA group (PFOA, 20 mg/kg/d, 5 mL/kg), PFOA + rutin group (PFOA, 20 mg/kg/d, 5 mL/kg; rutin, 20 mg/kg/d, 5 mL/kg). Mice were exposed to PFOA for 28 days by gavage once daily in the presence or absence of rutin. Histopathological observations demonstrated that rutin treatment during PFOA exposure can reduce structural damage to testis and epididymis such as atrophy of spermatogenic epithelium and stenosis of epididymal lumen, while increase in the number and layers of spermatogenic cells. Biochemical detection demonstrated that rutin can reduce 8-hydroxy-2'-desoxyguanosine (8-OHdG) concentration in the serum and testis tissues. Rutin can also ameliorate glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) content, and reduce malondialdehyde (MDA) and total cholesterol (TC) content in testis tissues. Biotin tracking immunofluorescence and transmission electron microscopy demonstrated that rutin can ameliorate BTB structural damage during PFOA exposure. Rutin ameliorated the stress expression of tight junction proteins occludin and claudin-11. In conclusion, our findings suggested that rutin has a degree of protection in reproductive and BTB damage, which could put forward a new perspective on the application of rutin to prevent reproductive damage.

Nickel induces blood-testis barrier damage through ROS-mediated p38 MAPK pathways in mice

Nickel (Ni) is an essential common environmental contaminant, it is hazardous to male reproduction, but the precise mechanisms are still unknown. Blood-testis barrier (BTB), an important testicular structure consisting of connections between sertoli cells, is the target of reproductive toxicity caused by many environmental toxins. In this study, ultrastructure observation and BTB integrity assay results indicated that NiCl2 induced BTB damage. Meanwhile, BTB-related proteins including the tight junction (TJ), adhesion junction (AJ) and the gap junction (GJ) protein expression in mouse testes as well as in sertoli cells (TM4) were significantly decreased after NiCl2 treatment. Next, the antioxidant N-acetylcysteine (NAC) was co-treated with NiCl2 to study the function of oxidative stress in NiCl2-mediated BTB deterioration. The results showed that NAC attenuated testicular histopathological damage, and the expression of BTB-related proteins were markedly reversed by NAC co-treatment in vitro and vivo. Otherwise, NiCl2 activated the p38 MAPK signaling pathway. And, NAC co-treatment could significantly inhibit p38 activation induced by NiCl2 in TM4 cells. Furthermore, in order to confirm the role of the p38 MAPK signaling pathway in NiCl2-induced BTB impairment, a p38 inhibitor (SB203580) was co-treated with NiCl2 in TM4 cells, and p38 MAPK signaling inhibition significantly restored BTB damage induced by NiCl2 in TM4 cells. These results suggest that NiCl2 treatment destroys the BTB, in which the oxidative stress-mediated p38 MAPK signaling pathway plays a vital role.

Switching from high-fat diet to normal diet ameliorate BTB integrity and improve fertility potential in obese male mice

Obesity is a prominent risk factor for male infertility, and a high-fat diet is an important cause of obesity. Therefore, diet control can reduce body weight and regulate blood glucose and lipids, but it remains unclear whether it can improve male fertility and its mechanism. This study explores the effects of switching from a high-fat diet (HFD) to a normal diet (ND) on the fertility potential of obese male mice and its related mechanisms. In our study, male mice were separated into three groups: normal diet group (NN), continuous high-fat diet group (HH), and return to normal diet group (HN). The reproductive potential of mice was tested through cohabitation. Enzymatic methods and ELISA assays were used to measure metabolic indicators, follicle-stimulating hormone (FSH) levels and intratesticular testosterone levels. Transmission electron microscopy and immunofluorescence with biotin tracers assessed the integrity of the blood-testis barrier (BTB). Malondialdehyde (MDA), superoxide dismutase (SOD), and reactive oxygen species (ROS) were inspected for the assessment of oxidative stress. The expression and localization of BTB-related proteins were detected through the immunoblot and immunofluorescence. The mice in the high-fat diet group indicated increased body weight and epididymal fat weight, elevated serum TC, HDL, LDL, and glucose, decreased serum FSH, and dramatic lipid deposition in the testicular interstitium. Analysis of fertility potential revealed that the fertility rate of female mice and the number of pups per litter in the HH group were significantly reduced. After the fat intake was controlled by switching to a normal diet, body weight and epididymal fat weight were significantly reduced, serum glucose and lipid levels were lowered, serum FSH level was elevated and the deposition of interstitial lipids in the testicles was also decreased. Most significantly, the number of offspring of male mice returning to a normal diet was significantly increased. Following further mechanistic analysis, the mice in the sustained high-fat diet group had disrupted testicular BTB integrity, elevated levels of oxidative stress, and abnormal expression of BTB-related proteins, whereas the restoration of the normal diet significantly ameliorated the above indicators in the mice. Our study confirms diet control by switching from a high-fat diet to a normal diet can effectively reduce body weight, ameliorate testicular lipotoxicity and BTB integrity in male mice, and improve fertility potential, providing an effective treatment option for obese male infertility.

The impact of dietary fructose on gut permeability, microbiota, abdominal adiposity, insulin signaling and reproductive function

The excessive intake of fructose in the regular human diet could be related to global increases in metabolic disorders. Sugar-sweetened soft drinks, mostly consumed by children, adolescents, and young adults, are the main source of added fructose. Dietary high-fructose can increase intestinal permeability and circulatory endotoxin by changing the gut barrier function and microbial composition. Excess fructose transports to the liver and then triggers inflammation as well as de novo lipogenesis leading to hepatic steatosis. Fructose also induces fat deposition in adipose tissue by stimulating the expression of lipogenic genes, thus causing abdominal adiposity. Activation of the inflammatory pathway by fructose in target tissues is thought to contribute to the suppression of the insulin signaling pathway producing systemic insulin resistance. Moreover, there is some evidence that high intake of fructose negatively affects both male and female reproductive systems and may lead to infertility. This review addresses dietary high-fructose-induced deteriorations that are obvious, especially in gut permeability, microbiota, abdominal fat accumulation, insulin signaling, and reproductive function. The recognition of the detrimental effects of fructose and the development of relevant new public health policies are necessary in order to prevent diet-related metabolic disorders.

Involvement of p38 MAPK in Leydig cell aging and age-related decline in testosterone

INTRODUCTION

Age-related decline in testosterone is associated with Leydig cell aging with impaired testosterone synthesis in aging. Obesity accelerates the age-related decline in testosterone. However, the mechanisms underlying the Leydig cell aging and the effects of obesity on Leydig cell aging remain unclear.

METHOD

Natural aging mice and diet-induced obese mice were used to assess the process of testicular Leydig cell senescence with age or obesity. Bioinformatic analysis of the young and aged human testes was used to explore key genes related Leydig cell aging. Leydig cell-specific p38 MAPK knockout (p38LCKO) mice were used to further analyze the roles of p38 MAPK in Leydig cell aging. The levels of testosterone and steroidogenic enzymes, activity of p38 MAPK, aging status of Leydig cells, and oxidative stress and inflammation of testes or Leydig cells were detected by ELISA, immunoblotting, immunofluorescence, and senescence-associated β-galactosidase (SA-β-Gal) staining analysis, respectively.

RESULT

The serum testosterone level was significantly reduced in aged mice compared with young mice. In the testis of aged mice, the reduced mRNA and protein levels of LHCGR, SRB1, StAR, CYP11A1, and CYP17A1 and the elevated oxidative stress and inflammation were observed. KEGG analysis showed that MAPK pathway was changed in aged Leydig cells, and immunoblotting displayed that p38 MAPK was activated in aged Leydig cells. The intensity of SA-β-Gal staining on Leydig cells and the number of p21-postive Leydig cells in aged mice were more than those of young mice. Similar to aged mice, the testosterone-related indexes decreased, and the age-related indexes increased in the testicular Leydig cells of high fat diet (HFD) mice. Aged p38LCKO mice had higher levels of testosterone and steroidogenic enzymes than those of age-matched wild-type (WT) littermates, with reduced the intensity of SA-β-Gal staining and the expression of p21 protein.

CONCLUSION

Our study suggested that obesity was an important risk factor for Leydig cell aging. p38 MAPK was involved in Leydig cell aging induced by age and obesity. The inhibition of p38 MAPK could delay Leydig cell aging and alleviate decline in testosterone.

Beneficial role of naringin against methotrexate-induced injury to rat testes: biochemical and ultrastructural analyses

Background

Methotrexate (MTX) is a commonly used chemotherapeutic drug that has adverse toxic effects on germ cells. Naringin (NG) is a natural flavanone glycoside, with different phytotherapeutic applications, and its possible protective effects against MTX-induced testicular tissue damage were investigated in this study.

Methods

Low and high doses of NG (40 and 80 mg/kg/day) were given for 10 days by intraperitoneal (i.p.) injection and MTX (20 mg/kg i.p.) was given at the 4th day of the experiment, with or without NG in rats.

Results

The obtained results showed that exposure to MTX increased malondialdehyde (MDA) levels and nitric oxide (NO) production compared with the control. In the meantime, MTX depleted catalse (CAT), superoxide dismutase (SOD), glutathione reductase (GR), glutathione peroxidase (GPx), and reduced glutathione (GSH) in the testicular tissue. Further, serum testosterone levels were significantly decreased in the MTX group. NG significantly counteracted the aforementioned effects of MTX; however, NG80 was more effective in restoring SOD, GR, MDA and NO. Interestingly, NG80 achieved a better improvement in the ultrastructural pattern of the testicular cells in MTX-exposed rats.

Conclusion

These results indicated, for the first time, that NG could be a potential candidate therapy against MTX-reprotoxic impacts.

Nanosized Titanium Dioxide Induced Apoptosis and Abnormal Expression of Blood-Testis Barrier Junction Proteins Through JNK Signaling Pathway in TM4 Cells

Nanosized titanium dioxide (nano-TiO₂) has been widely used in consumer products. It can cross the blood-testis barrier (BTB), and it has adverse effects on the male reproductive system. However, the specific mechanism has not been fully elucidated. The purpose of this study was to understand the role of the JNK signaling pathway in the apoptosis and abnormal expression of BTB junction proteins induced by nano-TiO₂ in TM4 cells. After different concentration of nano-TiO₂ treatments, the cell viability, apoptosis, mitochondrial membrane potential (Δψm), BTB junction proteins (Claudin-11, ZO-1, β-catenin), apoptosis-related proteins (Bax, Bcl-2, cleaved caspase-9, cleaved caspase-3), and phosphorylated (p)-JNK protein were examined. The results showed that cell viability, apoptosis rates, Δψm, and apoptosis-related protein levels changed in a concentration-dependent manner. Cell viability decreased significantly from 100 μg/mL nano-TiO₂ group. Apoptosis rates increased significantly from 150 μg/mL nano-TiO₂ group, and Δψm decreased significantly from 150 μg/mL nano-TiO₂ group. The protein levels of Bax, cleaved caspase-9, and cleaved caspase-3 increased significantly from 150 μg/mL nano-TiO₂ group, and the protein level of Bcl-2 decreased significantly from 100 μg/mL nano-TiO₂ group. The protein level of p-JNK increased significantly from 100 μg/mL nano-TiO₂ group. Abnormal expression of ZO-1 and β-catenin started from 150 μg/mL nano-TiO₂ group, and abnormal expression of Claudin-11 started from 100 μg/mL nano-TiO₂ group. Cells were treated with JNK inhibitor SP100625 to determine whether the changes of the above indicators in the concentration of 150 μg/mL nano-TiO₂ group can be reversed. We found that SP100625 at 20 μM significantly reversed these effects. These results highlighted that nano-TiO₂ could activate the JNK signaling pathway to induce mitochondria-mediated apoptosis and abnormal expression of BTB junction proteins in TM4 cells.

Histomorphometric and oxidative evaluation of the offspring's testis from type 2 diabetic female rats treated with metformin and pentoxifylline

Type 2 diabetes mellitus (T2D) during pregnancy is characterized by high levels of reactive oxygen species and pro-inflammatory factors in the placenta. Once these reactive species reach the foetus, they trigger physiological adaptations that allow the foetus to survive, but programme the organism to develop metabolic disorders in adulthood. The male reproductive system is highly susceptible to foetal programming. This study aimed to investigate the effects of intrauterine exposure to T2D on testicular histomorphometry and redox homeostasis of adult rats and evaluate the effects of maternal treatment with metformin and pentoxifylline. Female rats were induced to T2D, then treated with metformin and pentoxifylline, or co-treated with both drugs. The females were mated, the male offspring were sacrificed on postnatal day 90, and the testicles were collected for analysis. Metformin protected the tubular compartment, with the maintenance of the Sertoli cell population and daily sperm production. Pentoxifylline attenuated the effects of diabetes on Leydig cells, in addition to stimulating testosterone production and lowering lipid peroxidation. Intrauterine exposure to T2D results in important testicular alterations that compromise gonadal function, and the co-treatment with metformin and pentoxifylline may represent a promising therapy that attenuates these effects by combining the positive influences in both the tubular and interstitial compartments of the testicular parenchyma.

Apocynin Ameliorates Testicular Toxicity in High-Fat Diet-Fed Rats By Regulating Oxidative Stress

Objective: The purpose of this study was to examine the effects of apocynin (APC), an inhibitor of NADPH oxidase (NOX), on high-fat diet (HF)-induced testis cytotoxicity. Methods: Wistar albino rats were divided into three groups as control, HF and HF+APC groups. Rats in HF and HF+APC groups were fed using HF for 16 weeks and in the last four weeks of this period vehicle solution or APC (25 mg/kg) was administered orally five days a week, respectively. Control group was fed with standart lab chow for 16 weeks. Cholesterol, triglyceride, high-density lipoproteins, leptin, estrogen, testosterone, LH and FSH were estimated in blood serum. Sperm parameters were analysed from the epididymis. Testicular malondialdehyde, 8‐hydroxy‐2‐deoxyguanosine, glutathione, superoxide dismutase and myeloperoxidase levels were estimated biochemically. Testicular morphology, proliferative, apoptotic and NOX2-positive cells were analysed histologically. HF-induced obesity caused significant alterations in serum lipid and hormone profiles. Testicular malondialdehyde, 8‐hydroxy‐2‐deoxyguanosine, and myeloperoxidase levels increased, glutathione and superoxide dismutase levels decreased in this group. Moreover, altered sperm parameters, increased degenerated seminiferous tubules, apoptotic and NOX2- positive cells and decreased proliferative cells were observed in the HF group. All these biochemical and histological alterations improved in the HF+APC group. Conclusion: HF-induced obesity causes altreations in lipid values, sperm parameters and testicular morphology by increasing oxidative stress through NOX2 activity. Apocynin might prevent testis damage via regulating oxidant/antioxidant balance.

Bibliometric and visual analysis of blood-testis barrier research

Background: Extensive research on the blood-testis barrier has been undertaken in recent years. However, no systematic bibliometric study has been conducted on this subject. Our research aimed to identify the hotspots and frontiers of blood-testis barrier research and to serve as a guide for future scientific research and decision-making in the field.

Methods: Studies on the blood-testis barrier were found in the Web of Science Core Collection. VOSviewer, CiteSpace, and Microsoft Excel were used to conduct the bibliometric and visual analyses.

Results: We found 942 blood-testis barrier studies published in English between 1992 and 2022. The number of annual publications and citations increased significantly between 2011 and 2022, notably in the United States. China and the United States, the US Population Council, Endocrinology, and Cheng C. Yan were the most productive countries, institution, journal, and author, respectively. The study keywords indicated that blood-testis barrier research involves a variety of compositional features (tight junctions, cytoskeleton, adherens junctions), cell types (Sertoli cells, germ cells, Leydig cells, stem cells), reproductive toxicity (cadmium, nanoparticles, bisphenol-a), and relevant mechanisms (spermatogenesis, apoptosis, oxidative stress, dynamics, inflammation, immune privilege).

Conclusion: The composition and molecular processes of the blood-testis barrier as well as the blood-testis barrier in male infertility patients are the primary research hotspots in this field. In addition, future research will likely focus on treatment and the development of novel medications that target signal pathways in oxidative stress and apoptosis to preserve the blood-testis barrier. Further studies must extend to clinical diagnosis and therapy.

Metformin Exhibits an Attractive Antineoplastic Effect on Human Endometrial Cancer by Regulating the Hippo Signaling Pathway

Metformin, the first-line oral antidiabetic medicine, has shown great antineoplastic potential in various cancer types, despite an unclear mechanism. This study aimed to elucidate the possible mechanism of metformin as a chemotherapy agent with less reproductive and genetic toxicity in human endometrial cancer. The type I endometrial carcinoma cell lines Ishikawa and RL95-2 were treated with metformin. Cell functions, such as proliferation, migration, and invasion, were analyzed. Flow cytometry was performed for cell cycle and apoptosis analyses. Simultaneously, RT-qPCR and western blotting were performed to explore the possible mechanism. Moreover, YAP1 knockout Ishikawa cells were established via lentivirus to demonstrate the underlying mechanism. The results showed that metformin mediated Ishikawa and RL95-2 cell growth inhibition in a dose- and time-dependent manner. The IC50 values of metformin in Ishikawa and RL95-2 cells were 10 mM and 8 mM, respectively. The migration and invasion abilities were also inhibited in the metformin-treated group using wound healing assays and transwell migration and invasion assays, and Ishikawa and RL95-2 cells were arrested in the G1 or G2 phase, respectively. Moreover, the cell proportions of cells in both early and late apoptosis stages were dramatically elevated when treated with metformin, as was the ratio of Bax/Bcl-2 expression. Additionally, the expression levels of YAP1 mRNA and protein in the treatment group were much lower than those in the control group. The cellular behaviors of YAP1 knockout Ishikawa cells were similar to those in the metformin-treated group. Our results demonstrated that it is an attractive alternative to cytotoxic chemotherapy in human endometrial cancer, and YAP of the Hippo pathway may be a potential molecular target. This study provides novel ideas for the adjuvant therapy of endometrial cancer patients, especially for women with strong fertility desires and demands.

Cannabis and metformin on diabetic male Wistar rat sperm and reproductive organ parameters

Purpose

Cannabis use has reportedly increased in type 2 diabetic users as a possible co-treatment for associated pain and inflammation. Both cannabis and metformin (an anti-diabetic drug) have a limited number of studies completed on their effect on male reproductive parameters in a diabetic model. This study determined if cannabis and metformin administration alter various reproductive parameters in diabetic male rats.

Methods

Male Wistar rats (n = 35) were fed on a high fat diet and injected with streptozotocin (30 mg/kg rat) to induce a type-2 diabetic model. Treatment groups received cannabis based on Delta-9-Tetrahydrocannabinol (THC) concentrations of 1.25, 2.5 and 5 mg/kg per rat and metformin (50 mg/kg) every alternate day for 10 weeks. Organ weight; serum testosterone levels and sperm count, motility, lipid peroxidation, citrate synthase and lactate dehydrogenase activities were measured.

Results

Cannabis treatment induced a significant concentration dependent decrease in sperm motility at 5 mg/kg rat THC (P = 0.009) administration. Metformin significantly (P = 0.035) increased sperm counts and lactate dehydrogenase activity (P = 0.002). Both cannabis and metformin negatively affected testosterone concentrations.

Conclusions

Cannabis needs to be used cautiously as an alternative treatment in diabetic males based on the negative effects observed for the various reproductive parameters in this diabetic rat model.

Ameliorative effect of betulinic acid against zearalenone exposure triggers testicular dysfunction and oxidative stress in mice via p38/ERK MAPK inhibition and Nrf2-mediated antioxidant defense activation

Zearalenone (ZEA) is a nonsteroidal estrogenic mycotoxin, which mainly contaminates grains and has estrogen-like effects on the reproductive system. Betulinic acid (BA), a natural lupane-type pentacyclic triterpene, has anti-oxidative and anti-inflammatory properties. This study aimed to investigate whether BA alleviates ZEA-induced testicular damage and explore the possible mechanism. Here, BA ameliorated testicular damage by mitigating the disordered arrangement of seminiferous tubules, the exfoliation of lumen cells, and the increase of cell apoptosis caused by ZEA. Meanwhile, BA alleviated ZEA-triggered testicular damage by restoring hormone levels and sperm motility, and reconstructing the blood-testis-barrier. Moreover, BA alleviated ZEA-exposed testicular oxidative stress by activating Nrf2 pathway. Furthermore, BA moderated ZEA-evoked testicular inflammation by inhibiting p38/ERK MAPK pathway. Overall, our results revealed that BA has a therapeutic protective effect on ZEA-induced testicular injury and oxidative stress via p38/ERK MAPK inhibition and Nrf2-mediated antioxidant defense activation, which provides a viable alternative to alleviate ZEA-induced male reproductive toxicology.

Oxidative Stress in Men with Obesity, Metabolic Syndrome and Type 2 Diabetes Mellitus: Mechanisms and Management of Reproductive Dysfunction

Reactive oxygen species (ROS) are critical physiological mediators of cellular function, including male fertility. When ROS exceed antioxidant regulation, oxidative stress occurs which is detrimental to cellular function. Oxidative stress has been found to be a central mediator of obesity, metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM), as well as with male infertility. Human studies have correlated testicular oxidative stress in obese males, and animal studies have further provided insight into potential mechanisms of action. Management of oxidative stress is not well defined. Appropriate nutrition and exercise can be recommended for all diabetic patients, and weight loss for obese patients with MetS and T2DM. Consideration of dietary supplements including micronutrients, antioxidants or medicinal herbs are recommended. Metformin may also offer benefits on testicular oxidative stress and fertility parameters. Significantly more research on causation, mechanisms, clinical assessments and appropriate management of infertility on obesity, MetS and T2DM is still required.

Apoptosis and blood-testis barrier disruption during male reproductive dysfunction induced by PAHs of different molecular weights

The association between polycyclic aromatic hydrocarbons (PAHs) and male reproductive dysfunction has attracted increasing attention. The purpose of this study was to compare the male reproductive toxicity of multiple PAHs and to investigate the underlying molecular mechanisms. TM4 cells (mouse testicular Sertoli cells, SCs) were treated with benzo(a)pyrene (BaP), pyrene (Py), fluoranthene (Fl) and phenanthrene (Phe) (0, 0.1, 1, 10, 50, or 100 μM) for varying time points (4, 12, 24, or 48 h), and male C57BL/6 mice were administered BaP and Py (0, 10, 50, or 100 mg/kg body weight) for 14 days based on the cell experimental results. Histopathological examination, western blotting, ELISA, biochemical assays, RT-PCR, flow cytometry, JC-1 staining and trans-epithelium electrical resistance (TEER) measurements were used to assess apoptosis, blood-testis barrier (BTB) integrity, intracellular calcium ([Ca²⁺]_i) concentrations and oxidative stress (OS). The results revealed that the mRNA levels and enzymatic activities of CYP450 and GST family members; levels of ROS, MDA, cleaved caspase 3 (c-caspase 3), caspase 9, Bax, and cytochrome C (CytC); and numbers of TUNEL-positive cells were significantly increased by BaP and Py, while levels of AhR, GSH, SOD, CAT, Bcl-2 and ΔΨm were decreased. Additionally, BaP and Py notably interfered with tight junctions (TJs) and adherens junctions (AJs) in the BTB. Intriguingly, BaP, but not Py, induced [Ca²⁺]_i overload and gap junction (GJ) destruction. There was no dramatic effect of Fl and/or Phe on any of the above parameters except that slight cytotoxicity was observed with higher doses of Fl. Collectively, these findings showed that BaP and Py elicited SC apoptosis and BTB disruption involving mitochondrial dysfunction and OS, but [Ca²⁺]_i fluctuation and GJ injury were only observed with BaP-induced reproductive toxicity. The male reproductive toxicity of the selected PAHs was ranked in the order of BaP > Py > Fl > Phe.

Oxidative Stress and Male Infertility: Evidence From a Research Perspective

Male fertility potential can be influenced by a variety of conditions that frequently coincide. Spermatozoa are particularly susceptible to oxidative damage due to their limited antioxidant capacity and cell membrane rich in polyunsaturated fatty acids (PUFAs). The role of oxidative stress (OS) in the etiology of male infertility has been the primary focus of our Stellenbosch University Reproductive Research Group (SURRG) over the last 10 years. This review aims to provide a novel insight into the impact of OS on spermatozoa and male reproductive function by reviewing the OS-related findings from a wide variety of studies conducted in our laboratory, along with those emerging from other investigators. We will provide a concise overview of the production of reactive oxygen species (ROS) and the development of OS in the male reproductive tract along with the physiological and pathological effects thereof on male reproductive functions. Recent advances in methods and techniques used for the assessment of OS will also be highlighted. We will furthermore consider the current evidence regarding the association between OS and ejaculatory abstinence period, as well as the potential mechanisms involved in the pathophysiology of various systemic diseases such as obesity, insulin resistance, hypertension, and certain mental health disorders which have been shown to cause OS induced male infertility. Finally, special emphasis will be placed on the potential for transferring and incorporating research findings emanating from different experimental studies into clinical practice.

Therapeutic Effects of Bee Bread on Obesity-Induced Testicular-Derived Oxidative Stress, Inflammation, and Apoptosis in High-Fat Diet Obese Rat Model

Obesity is a debilitating disorder with a variety of problems including oxidative stress, inflammation, and apoptosis. The aim of our study was to investigate the therapeutic role of bee bread on oxidative stress, apoptosis, and inflammation in the testis of obese rats. Thirty-two adult male Sprague Dawley rats, with weights between 230–300 g, were distributed into four groups (n = 8/group), namely normal control (C), obese (Ob), obese + BB or obese + OR [high-fat diet (HFD) for 6 weeks then HFD plus bee bread or orlistat for another 6 weeks] groups. Bee bread (0.5 g/kg) or orlistat (10 mg/kg/day) was diluted with distilled water and administered daily for 6 weeks by oral gavage. There were significant decreases in the activities of antioxidant enzymes [glutathione-S-transferase (GST), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), glutathione reductase (GR)], glutathione (GSH)] and total antioxidant capacity (TAC) levels and mRNA expressions of nuclear factor erythroid 2–related factor 2 (Nrf2), superoxide dismutase (Sod), catalase (Cat) and glutathione peroxidase (Gpx) in the obese group relative to the control group. Meanwhile, the mRNA levels of pro-inflammatory markers, namely: inducible nitric oxide synthase (Inos), nuclear factor kappa B (Nf-κβ), tumour necrotic factor α (Tnf-α) and interleukin 1β (Il-1β) were significantly increased while interleukin (Il-10) was decreased in the obese group relative to the control group. Further, proliferating cell nuclear antigen (PCNA) immunoexpressions decreased while cleaved caspase-3 immunohistochemical staining increased significantly in the obese group, in addition to increases in the mRNA levels of p53, Bax, Caspases-8, 9 and 3, relative to the control group. Treatment with bee bread showed increases in antioxidant enzymes and PCNA immunoexpression, as well as decreases in inflammation and apoptosis markers in the testes. This study has shown that bee bread has therapeutic effects against oxidative stress, inflammation, apoptosis in the testis of HFD-induced obese male rats, thereby suggesting its role as a natural supplement capable of treating obesity-induced male reproductive impairment.

Restoring Impaired Fertility Through Diet: Observations of Switching From High-Fat Diet During Puberty to Normal Diet in Adulthood Among Obese Male Mice

BACKGROUND

Obesity is associated with a decrease in testicular function, yet the effects and mechanisms relative to different stages of sexual development remain unclear. The aim of this study is to determine whether high-fat diet-induced obesity impairs male fertility during puberty and in adulthood, and to ascertain its underlying mechanisms. This study aims to further reveal whether restoring to a normal diet can improve impaired fertility.

METHODS

Male mice were divided into 6 groups: the group N and H exposed to a normal diet or high-fat diet during puberty. The group NN or NH were further maintained a normal diet or exposed to high-fat diet in adulthood, the group HH or HN were further maintained high-fat diet or switched to normal diet in adulthood. Metabolic parameters, fertility parameters, testicular function parameters, TUNEL staining and testicular function-related proteins were evaluated, respectively.

RESULTS

The fertility of the mice in the high-fat diet group was impaired, which validated by declines in pregnancy rates and litter weight loss. Further analysis demonstrated the increased level of oxidative stress, the increased number of spermatogenic cell apoptosis and decreased number of sperm and decreased acrosome integrity. The expression of steroidogenic acute regulatory (StAR) and spermatogenesis related proteins (WT-1) decreased. Fertility among the HN group recovered, accompanied by the recovery of metabolism, fertility and testicular function parameters, StAR and WT-1 expression.

CONCLUSIONS

The findings suggest that high-fat diet-induced obesity impairs male fertility during puberty and in adulthood. The loss of acrosome integrity, the increase of oxidative stress, the increase of cells apoptosis and the down-regulation of StAR and WT-1 may be the underlying mechanisms. Switching from high-fat diets during puberty to normal diets in adulthood can improve male fertility.

Endocrine disorders and fertility and pregnancy: An update

It is estimated that more and more couples suffer from fertility and pregnancy maintenance disorders. It is associated with impaired androgen secretion, which is influenced by many factors, ranging from genetic to environmental. It is also important to remember that fertility disorders can also result from abnormal anatomy of the reproductive male and female organ (congenital uterine anomalies - septate, unicornuate, bicornuate uterus; acquired defects of the uterus structure - fibroids, polyps, hypertrophy), disturbed hormonal cycle and obstruction of the fallopian tubes resulting from the presence of adhesions due to inflammation, endometriosis, and surgery, abnormal rhythm of menstrual bleeding, the abnormal concentration of hormones. There are many relationships between the endocrine organs, leading to a chain reaction when one of them fails to function properly. Conditions in which the immune system is involved, including infections and autoimmune diseases, also affect fertility. The form of treatment depends on infertility duration and the patient's age. It includes ovulation stimulation with clomiphene citrate or gonadotropins, metformin use, and weight loss interventions. Since so many different factors affect fertility, it is important to correctly diagnose what is causing the problem and to modify the treatment regimen if necessary. This review describes disturbances in the hormone secretion of individual endocrine organs in the context of fertility and the maintenance of pregnancy.

Acetate supplementation restores testicular function by modulating Nrf2/PPAR-γ in high fat diet-induced obesity in Wistar rats

Purpose

Several studies have established impaired testicular function in obese male population, including the young males with childhood obesity, contributing to increased male infertility, which is a universal trend in the last few decades. Short chain fatty acids (SCFAs) have been recently demonstrated to inhibit progression to metabolic comorbidities. The present study therefore hypothesized that SCFAs, acetate attenuates testicular dysfunction in high fat diet (HFD)-induced obese rat model, possibly by modulating Nrf2/PPAR-γ.

Methods

Adult male Wistar rats weighing 160-190 g were randomly allotted into three groups (n = 6/group): The groups received vehicle (distilled water), 40% HFD and sodium acetate (200 mg/kg) plus 40% HFD respectively. The administration lasted for 12 weeks.

Results

HFD caused obesity, which is characterized with increased body weight and visceral adiposity and insulin resistance/hyperinsulinemia. In addition, it increased testicular lipid deposition, malondialdehyde, pro-inflammatory mediators, lactate/pyruvate ratio, γ-Glutamyl transferase, and circulating leptin as well as decreased testicular glutathione, nitric oxide, Nrf2, PPAR-γ and circulating follicle stimulating hormone and testosterone without a significant change in testicular lactate dehydrogenase, blood glucose and luteinizing hormone when compared to the control group. Nevertheless, administration of acetate reversed the HFD-induced alterations.

Conclusion

The present results demonstrates that HFD causes obesity-driven testicular dysfunction, associated with testicular lipid deposition, oxidative stress, and inflammation. The study in addition suggests the restoration of testicular function in obese animals by acetate, an effect that is accompanied by elevated Nrf2/PPAR-γ.

Dietary high-fructose reduces barrier proteins and activates mitogenic signalling in the testis of a rat model: Regulatory effects of kefir supplementation

There are limited data on the influence of fructose rich diet on the male reproductive system. Kefir may have health beneficial effects, but its mechanism of action remains mostly unclear. Herein, we investigated the impact of dietary high fructose on tight junction proteins and mitogenic pathways in rat testis as well as their modulation by kefir supplementation. Twenty-two male Wistar rats (4 weeks old) were divided into the following three groups: Control; Fructose; Fructose + Kefir. Fructose was added to drinking water at concentration of 20% and administered to the rats for 15 weeks and kefir was supplemented by gavage once a day during final 6 weeks. Dietary fructose-induced testicular degeneration was associated with the downregulation of the blood-testis barrier proteins, claudin-11 and N-cadherin as well as SIRT1 expression in testicular tissue of rats. However, p38MAPK, p-p38MAPK and p-ERK1/2 levels were increased in testis of fructose-fed rats. Interestingly, JNK1 and p-JNK1 protein levels were decreased following this dietary intervention. Raf1, ERK1/2, and caspase 3 and TUNEL staining of the testis reveal the activation of apoptosis due to fructose intake. Kefir supplementation markedly promoted the expression of claudin-11, SIRT1, JNK1 and p-JNK1 but suppressed testicular mitogenic and apoptotic factors in fructose-fed rats.

Developmental phenotypic and transcriptomic effects of exposure to nanomolar levels of metformin in zebrafish

Metformin is found in the majority of lakes and streams in the United States, leading to widespread environmental exposure. Results of the present study indicate that extended duration metformin exposure at critical developmental periods leads to decreased survival rates in zebrafish (danio rerio), an NIH approved human model. Significant abnormalities are seen with extended duration metformin exposure from 4 h post fertilization up to 5 days post fertilization, although short term metformin exposure for 24 h at 4-5 days post fertilization did not lead to any significant abnormalities. Both extended and short term duration did however have an impact on locomotor activity of zebrafish, and several genes involved in neurological and cardiovascular development were differentially expressed after exposure to metformin. The changes seen in behavior, gene expression and morphological abnormalities caused by metformin exposure should be examined further in future studies in order to assess their potential human health implications as metformin prescriptions continue to increase worldwide.

Palliative effects of metformin on testicular damage induced by triptolide in male rats

As a widely existing traditional Chinese medicine component, TP (triptolide) has serious reproductive toxicity which causes severe damage to the reproductive system and limits its application prospect. TP and MET (metformin) have shown great potential in combined with each other in anticancer and anti-inflammatory. Whether metformin can resist the reproductive toxicity caused by triptolide, the effects of MET on TP-induced reproductive capacity has not been reported. In this study, metformin was used to investigate the therapeutic effect on reproductive toxicity induced by TP in rat. The results showed that metformin had significant therapeutic effects on oxidative stress damage, destruction of the blood-testosterone barrier and apoptosis. And it proved that its therapeutic effect is mainly to restore the structural and functional stability of testis through antioxidant stress. It will provide guidance for the treatment of reproductive toxicity caused by TP and the adjuvant detoxification of TP application.

Prestroke Metformin Use on the 1-Year Prognosis of Intracerebral Hemorrhage Patients with Type 2 Diabetes

Background

Although recent studies have focused on the use of metformin in treating ischemic stroke, there is little literature to support whether it can treat intracerebral hemorrhage (ICH). Therefore, this study is aimed at evaluating the possible effects of prestroke metformin (MET) on ICH patients with type 2 diabetes.

Methods

From January 2010 to December 2019, all first-ever ICH patients with type 2 diabetes from our hospitals were included. All discharged patients would receive a one-time follow-up at 1 year after admission. Death, disability, and recurrence events were recorded.

Results

We included 730 patients for analysis (the median age: 65 [IQR, 56-72] years and 57.7% was men). Of those patients, 281 (38.5%) had received MET before ICH (MET+), whereas 449 (61.5%) had not (MET−). MET (+) patients had a lower median baseline hematoma volume than did MET (-) patients (9.6 ml [IQR, 5.3-22.4 ml] vs. 14.7 ml [IQR, 7.9-28.6 ml]; P < 0.001). The inhospital mortality events were not significantly reduced in the MET (+) group compared with the MET (-) group (6.4% vs 8.9%, respectively; absolute difference, −2.5% [95% CI, −3.9% to −0.7%]; OR, 0.70 [95% CI, 0.39 to 1.27]; P = 0.22). The 1-year mortality events were not significantly reduced in the MET (+) group compared with the MET (-) group (14.1% vs 17.4%, respectively; absolute difference, −3.3% [95% CI, −5.1% to −1.8%]; OR, 0.73 [95% CI, 0.47 to 1.14]; P = 0.16). The 1-year disability events were not significantly reduced in the MET (+) group compared with the MET (-) group (28.4% vs 34.1%, respectively; absolute difference, −5.7% [95% CI, −8.2% to −3.3%]; OR, 0.77 [95% CI, 0.52 to 1.13]; P = 0.18). Finally, the recurrence rates in those two groups were not significantly different (MET [+] vs. MET [-]: 6.4% vs. 5.9%; absolute difference, 0.5% [95% CI, 0.2% to 1.3%]; OR, 1.08 [95% CI, 0.51 to 2.28]; P = 0.84).

Conclusions

Pre-ICH metformin use was not associated with inhospital mortality and 1-year prognosis in diabetic ICH patients.

Moderate calorie restriction ameliorates reproduction via attenuating oxidative stress-induced apoptosis through SIRT1 signaling in obese mice

Background

Obesity is a growing global public health problem. It has been associated with diabetes, cardiovascular disease, cancer, and an increased risk of all-cause mortality, as well as infertility. Calorie restriction (CR) is an effective life intervention to defend against obesity. This study aimed to investigate the effects of long-term moderate CR on the reproductive function and underlying mechanisms in a mouse model of obesity.

Methods

Male C57BL/6 mice were randomized to two groups receiving either a standard diet (STD) or a high-fat diet (HFD) for 8 weeks to induce obesity. The HFD-induced obesity mice were further randomized into two groups: HFD group and CR group (reduced the mean amount of HFD by 25%). After 12 weeks, the body weight, testicular coefficients, fasting blood glucose (FBG), serum triglyceride (TG), and total cholesterol (TC) were detected and measured. The sperm quality was detected by an automatic sperm quality analyzer (SQA-V). The structure of testicular tissues was examined by hematoxylin and eosin (HE) staining. Testicular cell apoptosis was assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. The levels of NAD-dependent deacetylase sirtuin-1 (SIRT1) and antioxidative enzymes were detected in the testes.

Results

CR treatment reduced weight gain and increased testicle coefficients in HFD-induced obese mice. CR reduced the serum level of FBG, TG, and TC, and increased the serum levels of testosterone. Moreover, CR increased sperm count and motility, and sperm normality in obese mice. Furthermore, CR ameliorated the testicular morphological damage and cell apoptosis in obese mice. CR also attenuated the oxidative stress level and increased the protein expressions of SIRT1 in testicular tissues of obese mice.

Conclusions

Long-term moderate CR improves obese male fertility, probably by alleviating oxidative stress via activation of SIRT1 signaling.

Protective effects of bee bread on testicular oxidative stress, NF-κB-mediated inflammation, apoptosis and lactate transport decline in obese male rats

Oxidative stress, chronic inflammation and apoptosis are associated with obesity. Herein, we investigated the potential protective effect of bee bread, a natural bee product, on testicular oxidative stress, inflammation and apoptosis, as well as lactate transport in the testis of high-fat diet (HFD)-induced obese rats. Adult male Sprague-Dawley rats were either fed with normal chow (NC), HFD, HFD + bee bread (0.5 g/kg b.w./day) or HFD + orlistat (10 mg/kg b.w./day) for 12 weeks. Our results show significant decreases in the activities and mRNA expression of antioxidant genes (Nrf2, Sod, Cat and Gpx), with significant increase in pro-inflammatory (Nf-κb, Tnf-α, iNos, Il-1β) and pro-apoptotic (p53, Bax, Bax/Bcl2, Caspase-8, Caspase-9 and Caspase-3) genes in the testis of HFD group relative to the NC group. Furthermore, proliferating cell nuclear antigen (PCNA) was poorly expressed in the testis of the HFD group relative to the NC group. Similarly, the mRNA levels of glucose transporters (Glut1 and Glut3), monocarboxylate transporters (Mct2 and Mct4) and lactate dehydrogenase type C (Ldhc) decreased significantly, with decrease in lactate utilisation. Treatment with bee bread upregulated testicular antioxidant enzymes, downregulated inflammation and apoptosis, and increased PCNA immunoexpression, in addition to improving lactate transport. Taken together, our results suggest that bee bread is a promising natural product with the potential to improve male fertility.

Effects of short-term exposure to high-fat diet on histology of male and female gonads in rats

Obesity, which reaches an epidemic, is characterized by alterations in metabolic and hormonal profiles. Moreover, uncontrolled obesity may lead to development of diabetes type 2, which accounts for about 90% of all diabetic cases. In obesity, besides changes in metabolism, numerous co-morbidities are reported, e.g. disruptions of reproductive functions. Additionally, sex differences in development of this disease occur. We hypothesized that short-term exposure to high-fat diet (HFD; containing 50% of total energy from fat) would alter histology of testes and ovaries, and thus contribute to reproductive disruptions in male and female rats. Adult rats were fed ad libitum with HFD for 6-7 weeks and its effects on histology of testes and ovaries (n = 4/sex and treatment group) were studied using hematoxylin-eosin staining followed by microscopic analysis and compared to control (laboratory chow fed) group. We have found that in male rats fed with HFD there were: 1) decrease in diameter of seminiferous tubules due to smaller luminar diameter, and no change in epithelium height; 2) decrease in number of Sertoli cells; 3) no changes in number of spermatogonia and in percentage of semen in seminiferous tubules. In female rats exposed to HFD we have seen: 1) decrease in diameters of corpora lutea; 2) decrease in diameter of ovarian follicles types 7 and 8, but no changes in their number; 3) no changes in number of early primary follicles, primary follicles, and secondary follicles. We concluded that relatively short-term exposure to HFD in rats leads to changes in histology of both testes and ovaries, thus affecting reproductive functions.

Metformin Ameliorates Testicular Function and Spermatogenesis in Male Mice with High-Fat and High-Cholesterol Diet-Induced Obesity

The aim of this study was to investigate the effects of metformin supplementation on metabolic dysfunction, testicular antioxidant capacity, apoptosis, inflammation and spermatogenesis in male mice with high-fat and high-cholesterol diet-induced obesity. Forty male C57BL/6 mice were fed a normal diet (NC group, n = 10) or a high-fat and high-cholesterol diet (HFC group, n = 30) for 24 weeks, and mice randomly chosen from the HFC group were later treated with metformin for the final 8 weeks of HFC feeding (HFC + Met group, n = 15). Compared with the HFC group, the obese mice supplemented with metformin exhibited improved blood cholesterol, glucose and insulin resistance. The HFC group diminishes in the sperm motility and normal sperm morphology, while the poorer maturity of testicular spermatogenesis was improved by metformin treatment. The HFC group exhibited a higher estradiol level and a lower 17β-HSD protein expression. Further analyses showed that metformin treatment increased the activities of superoxide dismutase, catalase and glutathione peroxidase and reduced lipid peroxidation. Nevertheless, both the HFC and HFC + Met groups exhibited increased expressions of apoptosis and inflammation proteins in the testis. Metformin treatment ameliorated obesity-induced poor testicular spermatogenesis and semen quality through increasing the testosterone level and antioxidant capacity.

High fat diet impairs spermatogenesis by regulating glucose and lipid metabolism in Sertoli cells

AIMS

Sertoli cells (SCs) play an important role in the process of spermatogenesis. SCs provide energy for germ cells (GCs) and themselves through glycolysis and fatty acid oxidation (FAO) respectively. High fat diet (HFD) impairs spermatogenesis by damaging function of SCs, however whether HFD disrupts energy metabolism in SCs remains unclear.

MAIN METHODS

To explore this hypothesis, we built male Wistar rat model fed on HFD and cultured rats' primary SCs with palmitic acid (PA). Rats' fertility and sperm quality were evaluated in vivo. Glycolysis, lactate production and mitochondrial respiration were assessed by using extracellular flux analyzer, and the expression of enzymes involved in glucose and FAO was analyzed by Real-Time PCR or Western Blotting.

KEY FINDINGS

The showed that the sperm concentration and pups per litter significantly decreased in rats fed on HFD compared to those rats fed on normal diet. There was an elevation of lactate levels in testicular tissue of rats fed on HFD and primary SCs exposed to PA. In vitro, PA increased glycolytic flux, and lactate production, and the levels of carnitine palmitoyltransferase I (CPT1) and long chain acyl-CoA dehydrogenase (LCAD) which were two key enzymes for fatty acid β oxidation. Further analysis showed that mitochondrial respiration was impaired by PA, followed by the decrease in ATP turnover, maximal respiration and the increase in proton leak.

SIGNIFICANCE

Taken together, the elevated lactate level, lipid metabolism disorder and mitochondrial dysfunction caused by HFD lead to SCs dysfunction, which ultimately leads to decreased sperm quality.

The possible role of NF-κB1 Rs28362491 polymorphism in male fertility of Egyptian population

Male reproductive impairment is responsible for at least 50% of cases of couple infertility. Nuclear factor-kappa B (NF-κB) has been functionally linked to germ cell apoptosis, which may affect human fertility. The aim of this study was to determine the association between the rs28362491 SNP of the NF-κB1 gene and infertility in Egyptian men. In this case-control study, semen and blood samples of 247 infertile men, constituting the case group, and of 113 fertile healthy men as the control group were analysed. All study participants were genotyped for polymorphism of the NF-κB1 gene (rs28362491) by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Heterozygous I/D genotype of the NF-κB1 rs28362491 polymorphism was associated with a significantly lower risk of poor semen quality, including asthenozoospermia, astheno-teratozoospermia, and oligo-astheno-teratozoospermia, when compared to I/I genotype (odds ratio = 0.25, 0.26, 0.18, p < .0005, <.0005, <.0005) respectively. Overall, the presence of the D allele was associated with a significantly decreased risk of poor sperm quality as compared to the I allele (odds ratio = 0.56, 0.64, 0.49, p = .050, .038, .001). In conclusion, these results suggest that heterozygosity of the NF-κB1 gene may play a protecting role against male infertility in Egyptians.

Obesity and male infertility: Mechanisms and management

Obesity is considered a global health problem affecting more than a third of the population. Complications of obesity include cardiovascular diseases, type 2 diabetes mellitus, malignancy (including prostatic cancer), neurodegeneration and accelerated ageing. In males, these further include erectile dysfunction, poor semen quality and subclinical prostatitis. Although poorly understood, important mediators of obesity that may influence the male reproductive system include hyperinsulinemia, hyperleptinemia, chronic inflammation and oxidative stress. Obesity is known to disrupt male fertility and the reproduction potential, particularly through alteration in the hypothalamic-pituitary-gonadal axis, disruption of testicular steroidogenesis and metabolic dysregulation, including insulin, cytokines and adipokines. Importantly, obesity and its underlying mediators result in a negative impact on semen parameters, including sperm concentration, motility, viability and normal morphology. Moreover, obesity inhibits chromatin condensation, DNA fragmentation, increases apoptosis and epigenetic changes that can be transferred to the offspring. This review discusses the impact of obesity on the male reproductive system and fertility, including associated mechanisms. Furthermore, weight management strategies, lifestyle changes, prescription medication, and complementary and alternative medicine in the management of obesity-induced subfertility is discussed.

Pterostilbene Inhibits FcεRI Signaling through Activation of the LKB1/AMPK Pathway in Allergic Response

In this study, the role and mechanism of pterostilbene (Pts) in mast cell degranulation in vitro and in vivo were investigated. The results showed that Pts inhibited mast cell-mediated local passive allergic reactions in mice. In addition, treatment with Pts reduced both histamine release and calcium influx in rat peritoneal mast cells and RBL-2H3 cells and reduced IgE-mediated mast cell activation. Furthermore, the mechanism underlying Pts inhibition of mast cell signaling was probed via studying the effects of Pts on liver kinase B1 (LKB1), including the use of the LKB1 activator metformin and siRNA knockdown of LKB1. The data showed that Pts reduced the release of inflammatory mediators such as tumor necrosis factor-α, interleukin-6, leukotriene C4, and prostaglandin D2 in mast cells by activating the LKB1/adenosine monophosphate (AMP)-activated protein kinase (AMPK) signaling pathway. Furthermore, Pts inhibited phosphorylation of FcεRI and FcεRI-mediated degranulation in RBL-2H3 cells. These effects were attenuated after LKB1 knockdown. Taken together, Pts could inhibit FcεRI signaling through activation of the LKB1/AMPK signaling pathway in IgE-mediated mast cell activation. Thus, Pts might be an effective therapeutic agent for mast cell-mediated allergic diseases.