Testicular hypofunction caused by activating p53 expression induced by reactive oxygen species in varicocele rats

Experimental exploration of estrogenic effects of norethindrone and 17α-ethinylestradiol on zebrafish (Danio rerio) gonads

Synthetic progestins and xenoestrogens found in aquatic habitats are currently gaining attention on global scale. The current study aimed to investigate the time-and dose-dependent effects of synthetic progestin Norethindrone (NET; 100, 500 and 1000 ng/L) and estrogen 17α-ethinylestradiol (EE2; 100 ng/L) individually as well as in binary mixture (1000 ng/L NET + 100 ng/L EE2) on reproductive histology and transcriptional expression profile of genes in adult zebrafish. For this, 20 female (3.15 ± 0.18 cm & 0.33 ± 0.06 g) and 20 male zebrafish in each group (2.93 ± 0.13 cm & 0.29 ± 0.04 g) were exposed to drugs dissolved in water for 30 days in 12 L rectangular tanks. We found that both NET and EE2 exposure reduced the gonadosomatic index in females, while only EE2 exposure caused significant reduction in males (p ≤ 0.05). Interestingly, NET delayed oocyte maturation in females and accelerated spermatogenesis in males, while EE2 consistently suppressed sperm maturation throughout the experiment. Further, qRT-PCR results revealed differential expression pattern of the study genes (er-α, er-β1, er-β2, pgr, vegfaa and p53) in male and female zebrafish. Co-exposure indicated potential inconsistencies in steroidal function in mixtures rather than single exposures. Our findings imply that changes in gonadal histology after NET and EE2 exposure may result from unique regulation of steroid hormone receptors. Additionally, significantly reduced p53 levels (p ≤ 0.05) following co-exposure in both sexes may suggest an elevated risk of neoplastic transformations. Further research with mammalian models will help to explore the mechanisms behind differing effects of alone and co-exposures.

Lycopene improves testicular damage and sperm quality in experimentally induced varicocele: Relationship with apoptosis, hypoxia, and hyperthermia

Varicocele is considered the main reason for male infertility. Antioxidants are common drugs used to reduce the complications of varicocele in these patients. So, we investigated the effects of lycopene on sperm quality, testicular histology, and the expression of some genes in experimentally induced varicocele. Fifty adult male Wistar rats were divided into three groups: control (n = 12), sham (n = 5), and varicocele (n = 33) groups. After 2 months of induced varicocele, five rats were randomly sacrificed and induced varicocele was investigated in each group. Finally, 35 rats were divided into five groups: the control, varicocele, varicocele reserving solvent, and varicocele reserving lycopene (4 and 10 mg/kg) for 2 months. At the end of the experiment, sperm viability, membrane integrity, the expression of Bax, Bcl2, hypoxia (hypoxia‐inducible factor 1α [HIF1‐α]), heat‐shock protein (heat‐shock protein A2 [HSPA2]) genes, and the histology of testes were measured. The results showed a significant decrease in the sperm viability, membrane integrity, Johnson's score, and the expression of the Bcl2 gene in the varicocele group compared to the control group. Also, there was a significant increase in Bax, HSPA2, and HIF1‐α expressions in the varicocele group compared to the control group. Although the administration of lycopene (10 mg/kg) in rats with varicocele improved sperm viability and membrane integrity, Johnson's score, and Bax expression compared to the varicocele group. Our findings indicated that the administration of lycopene in the varicocele group improved sperm quality and testicular injury induced by varicocele via decreasing apoptosis.

COVID-19 and varicocele: the possible overlap factors and the common therapeutic approaches

Varicocele is recognized as one of the main attributable causes of male infertility which can affect spermatogenesis by various pathophysiological mechanisms. Recent studies have identified oxidative stress and reduction in antioxidant, hyperthermia, hypoxia, hormonal dysfunction, and inflammatory conditions as major factors in the pathophysiology of varicocele, all of which have known direct associations with the coronavirus disease 2019 (COVID-19) and can significantly increase the risk of detrimental COVID-19-related outcomes. Emerging data have shown an association between COVID-19 and inflammation, overproduction of cytokine, and other pathophysiological processes. The present review, summarizes the current understanding of the pathophysiology of varicocele and investigates the potential correlation between the severity of COVID-19 and the varicocele disease. In addition, various possible treatments which can be effective in both diseases were examined. Despite numerous challenges associated with the prevalence of COVID-19 in healthcare systems in infected countries, special attention should be given to maintaining a high level of care for complex patients with a pre-existing disease such as varicocele and providing appropriate practical advice for optimal control of the COVID-19 disease. This article is protected by copyright. All rights reserved.

Explore the effects of pulmonary fibrosis on sperm quality and the role of the PI3K/Akt pathway based on rat model

Researches were reported that respiratory diseases can lead to male infertility; however, it is unclear whether there is a relationship between pulmonary fibrosis (PF) and male infertility. This study examined the influence of PF on sperm quality and its mechanisms. The key signalling pathway of male infertility caused by PF was predicted based on bioinformatics research. After modelling, we evaluated semen quality. Real-time quantitative polymerase chain reaction and Western blotting were used to measure the protein and mRNA expression levels of phosphatidylinositol 3-kinase (PI3K), phosphorylation-protein kinase B (p-Akt) and B-cell lymphoma 2 (Bcl2) in rat testicular cells. Compared with group A (48.77 ± 4.67; 59.77 ± 4.79), the sperm concentration and total sperm viability of group B (8.44 ± 1.71; 15.39 ± 3.48) showed a downward trend (p < 0.05). Western blotting showed that the protein expressions of PI3K, p-Akt and Bcl2 in the testes of group B (0.30 ± 0.06; 0.27 ± 0.05; 0.15 ± 0.03) was significantly lower than those of group A (0.71 ± 0.07; 0.72 ± 0.06; 0.50 ± 0.06) (p < 0.05). The hypoxic environment induced by PF can inhibit the expression of PI3K, p-Akt and Bcl2 protein and eventually cause dysfunctional spermatogenesis.

Effects of Environmental and Pathological Hypoxia on Male Fertility

Male infertility is a widespread health problem affecting approximately 6%-8% of the male population, and hypoxia may be a causative factor. In mammals, two types of hypoxia are known, including environmental and pathological hypoxia. Studies looking at the effects of hypoxia on male infertility have linked both types of hypoxia to poor sperm quality and pregnancy outcomes. Hypoxia damages testicular seminiferous tubule directly, leading to the disorder of seminiferous epithelium and shedding of spermatogenic cells. Hypoxia can also disrupt the balance between oxidative phosphorylation and glycolysis of spermatogenic cells, resulting in impaired self-renewal and differentiation of spermatogonia, and failure of meiosis. In addition, hypoxia disrupts the secretion of reproductive hormones, causing spermatogenic arrest and erectile dysfunction. The possible mechanisms involved in hypoxia on male reproductive toxicity mainly include excessive ROS mediated oxidative stress, HIF-1α mediated germ cell apoptosis and proliferation inhibition, systematic inflammation and epigenetic changes. In this review, we discuss the correlations between hypoxia and male infertility based on epidemiological, clinical and animal studies and enumerate the hypoxic factors causing male infertility in detail. Demonstration of the causal association between hypoxia and male infertility will provide more options for the treatment of male infertility.

Expression of Hypoxia-Inducible Factor1-α in Varicocele Disease: a Comprehensive Systematic Review

Hypoxia has been suggested as an important pathophysiological feature in varicocele disease. On the other hand, the expression of hypoxia-inducible factor 1-alpha (HIF1-α) is associated with the incidence of hypoxia. In this study, we investigated the expression of HIF1-α in varicocele disease through a comprehensive systematic review. We searched PubMed, Scopus, Web of Science, and Embase databases to identify the related studies published up to February 2021. Human studies have demonstrated an increase in the HIF-1α protein expression in the internal spermatic vein (ISV) of the varicocele testicle. HIF-1α mRNA expression in the seminal plasma was significantly higher in infertile varicocele patient compared with fertile ones. Similarly, most animal studies demonstrated a significant increase in HIF-1α gene and protein expression in varicocele testicular tissue compared with control groups. The studies illustrated that hypoxia followed by increased expression of hypoxia-inducible factor 1-alpha (HIF1-α) mRNA and protein occurs in varicocele disease. Expression of HIF-1α regulates the expression of many genes, including VEGF, p53, GLUT, Bax, and Caspase-3, that could be involved in many of the varicocele pathophysiological effects such as DNA fragmentation and apoptosis of sperm cells. Further studies with a large number of patients are necessary and can provide more definitive evidence.

Potential therapeutic effects of Ulva lactuca water fraction on monosodium glutamate-induced testicular and prostatic tissue damage in rats

Male infertility is considered one of the most critical health problems that are expected to expand worldwide. Ulva lactuca is a species of green seaweeds which is known to be a rich source of many important nutrients. Accordingly, this study is designated to investigate the therapeutic role of Ulva lactuca water fraction (UL) against monosodium glutamate (MSG)-induced male reproductive system disorders in male rats. Ulva lactuca methanolic crude extract was prepared firstly, and then water-dissolved compounds of this crude methanolic extract were separated. Ulva lactuca water fraction active phenolic compounds were determined using high-performance liquid chromatography (HPLC). Thirty-two male rats were divided equally into four groups; male infertility was induced in sixteen experimental animals by MSG at dose of 15 mg/Kg for 45 days. Eight infertile animals were treated with 100 mg/Kg of Ulva lactuca water fraction for 30 days. The rest of the animals were divided into two control groups; one control group (eight animals) was used to study the effect of UL on healthy rats at dose of 100 mg/Kg for 30 days and healthy control group (eight animals). Semen quality parameters (concentration and motility ratio), serum testosterone, prostate-specific antigen (PSA), and phosphatases were estimated by using standard protocols. Moreover, prooxidants and endogenous antioxidant enzymes were measured in prostate and testis homogenates. In addition, relative expression of pro-inflammatory genes (inducible nitric oxide synthase (i-NOS), cyclooxygenase-2 (COX-2), tumor necrosis factor-α alpha (TNF-α), and tumor protein (P53)) were assessed in testicular and prostatic tissues. Finally, histological alterations were measured by hematoxylin and eosin (H&E) stain. Results revealed that Ulva lactuca water fraction contains active phenolic constituents responsible for its antioxidant bioactivity. Oral administration of MSG significantly induced histological alterations. Oxidative stress was observed with elevated levels of nitric oxide (NO), thiobarbituric acid reactive substances (TBARS), and xanthine oxidase (XO) activity in both testis and prostate tissues. MSG adversely affected prostate function via elevation of PSA, prostatic acid phosphatases (PAPs), and total acid phosphatases (TAPs). In addition, it upregulated pro-inflammatory genes in testis and prostate tissues. Meanwhile, MSG reduced serum testosterone, semen quality, and antioxidant enzyme activities (glutathione peroxidase (GPx), glutathione-s-transferase (GST), and superoxide dismutase (SOD)). Treatment with UL notably ameliorated the state of oxidative stress and downregulated the expression of pro-inflammatory gene markers. This study highlighted the potential efficacy of Ulva lactuca water fraction on MSG-induced male infertility in rats. Therapeutic effect of UL on oxidative stress and inflammation induced by MSG in testicular and prostatic tissues.

Relationship between aryl hydrocarbon receptor and spermatogenic dysfunction in male patients with varicocele

The main purpose of this project is to verify whether there is a difference in the expression of aryl hydrocarbon receptor (AhR) between varicocele (VC) and normal male semen, and determine whether there is a connection with the parameters of semen analysis. The risk factors of infertility in patients with VC were also studied. Semen samples were collected for semen analysis and Western blot. Logistic regression was used to investigate the risk factors associated with infertility in patients with VC. Men with VC had lower AhR expression compared to healthy men; correlation analysis results showed that: AhR expression in patients with VC group was significantly positively correlated with sperm concentration and sperm motility; significantly negatively correlated with the diameter of spermatic veins during Valsalva and the percentage of abnormal sperm morphology; the research results of related risk factors show that the risk of infertility of patients with grade III is 1.67 times that of patients with grades I and II. For each unit of abnormal sperm morphology, the risk of infertility increases 1.04 times. Sperm concentration, total sperm viability and each unit the expression of AhR protein decreases the risk of infertility by 3%, 9% and 11% respectively.

Pathophysiology and treatment options of varicocele: An overview

Varicocele is the most common correctable cause for male infertility, but not all men with varicocele are affected equally by this condition. The pathophysiology of varicocele-induced fertility remains ill-defined. While evidence suggests that oxidative stress remains a central factor, other mechanisms likely include scrotal hyperthermia, reflux of metabolites, hypoxia and cadmium accumulation. Microsurgical varicocelectomy remains the gold standard treatment option for infertile men with a clinically palpable varicocele and abnormal semen parameters. Newer evidence suggests a potential role for antioxidant supplementation and a meaningful role of varicocelectomy for patients destined for ART to improve pregnancy outcomes.

Aberrant Upregulation of Compensatory Redox Molecular Machines May Contribute to Sperm Dysfunction in Infertile Men with Unilateral Varicocele: A Proteomic Insight

Aims: To understand the molecular pathways involved in oxidative stress (OS)-mediated sperm dysfunction against a hypoxic and hyperthermic microenvironment backdrop of varicocele through a proteomic approach. Results: Protein selection (261) based on their role in redox homeostasis and/or oxidative/hyperthermic/hypoxic stress response from the sperm proteome data set of unilateral varicocele (UV) in comparison with fertile control displayed 85 to be differentially expressed. Upregulation of cellular oxidant detoxification and glutathione and reduced nicotinamide adenine dinucleotide (NADH) metabolism accompanied with downregulation of protein folding, energy metabolism, and heat stress responses were observed in the UV group. Ingenuity pathway analysis (IPA) predicted suppression of oxidative phosphorylation (OXPHOS) (validated by Western blotting [WB]) along with augmentation in OS and mitochondrial dysfunction in UV. The top affected networks indicated by IPA involved heat shock proteins (HSPs: HSPA2 and HSP90B1). Their expression profile was corroborated by immunocytochemistry and WB. Hypoxia-inducible factor 1A as an upstream regulator of HSPs was predicted by MetaCore. Occurrence of reductive stress in UV spermatozoa was corroborated by thiol redox status. Innovation: This is the first evidence of a novel pathway showing aberrant redox homeostasis against chronic hypoxic insult in varicocele leading to sperm dysfunction. Conclusions: Upregulation of antioxidant system and dysfunctional OXPHOS would have shifted the redox balance of biological redox couples (GSH/GSSG, NAD⁺/NADH, and NADP⁺/NADPH) to a more reducing state leading to reductive stress. Chronic reductive stress-induced OS may be involved in sperm dysfunction in infertile men with UV, where the role of HSPs cannot be ignored. Intervention with antioxidant therapy warrants proper prior investigation.

Seminal oxidation-reduction potential and sperm DNA fragmentation index increase among infertile men with varicocele

Varicocele is a common cause of male infertility. It is reported that low sperm concentration, motility and morphology are indicative of increased sperm DNA fragmentation index (DFI) in men with varicocele. Although research has been conducted into the relationship between varicocele and DFI, little is known about seminal oxidation-reduction potential (ORP) in varicocele patients. We assessed the relationship between varicocele with seminal ORP and sperm DFI in both fertile and infertile men. This prospective case-control study compared the findings from infertile men with varicocele to those of men with normal spermatogenesis without varicocele. Semen samples were collected and assessed using the WHO (2010) guidelines. ORP was measured (mV) and normalized to sperm concentration (mV/10⁶ sperm/mL). DFI was measured using the sperm chromatin structure assay (SCSA) method. For group comparisons, only samples with a concentration >1 × 10⁶ sperm/mL were included. Infertile men with varicocele had significantly lower mean sperm concentration, motility and total sperm count. Conversely, infertile men with varicocele had a significantly higher mean serum FSH level, and higher ORP and DFI values than fertile controls. ORP was higher in patients with varicocele and positively correlated with DFI (p < 0.01). ORP and DFI showed significant negative correlations with semen parameters (sperm concentration, motility and total sperm count) in infertile men with a varicocele.

A new paradigm regarding testicular thermoregulation in ruminants?

Increased testicular temperature reduces percentages of morphologically normal and motile sperm and fertility. Specific sperm defects appear at consistent intervals after testicular hyperthermia, with degree and duration of changes related to intensity and duration of the thermal insult. Regarding pathogenesis of testicular hyperthermia on sperm quality and fertility, there is a long-standing paradigm that: 1) testes operate near hypoxia; 2) blood flow to the testes does not increase in response to increased testicular temperature; and 3) an ensuing hypoxia is the underlying cause of heat-induced changes in sperm morphology and function. There are very limited experimental data to support this paradigm, but we have data that refute it. In 2 × 3 factorial studies, mice and rams were exposed to two testicular temperatures (normal and increased) and three concentrations of O₂ in inspired air (hyperoxia, normoxia and hypoxia). As expected, increased testicular temperature had deleterious effects on sperm motility and morphology; however, hyperoxia did not prevent these changes nor did hypoxia replicate them. In two follow-up experiments, anesthetized rams were sequentially exposed to: 1) three O₂ concentrations (100, 21 and 13% O₂); or 2) three testicular temperatures (33, 37 and 40 °C). As O₂, decreased, testis maintained O₂ delivery and uptake by increasing testicular blood flow and O₂ extraction, with no indication of anaerobic metabolism. Furthermore, as testicular temperature increased, testicular metabolic rate nearly doubled, but increased blood flow and O₂ extraction prevented testicular hypoxia and anaerobic metabolism. In conclusion, our data, in combination with other reports, challenged the paradigm that testicular hyperthermia fails to increase testicular blood flow and the ensuing hypoxia disrupts spermatogenesis.

Transfer of orally administered ZnO:Eu nanoparticles through the blood-testis barrier: the effect on kinetic sperm parameters and apoptosis in mice testes

Zinc-based nanoparticles are promising materials for various applications, including in biomedicine. The aim of our study was to determine the effect of fluorescent europium-doped zinc oxide nanoparticles (ZnO:Eu NPs) on sperm parameters, cell apoptosis and integrity of the blood-testis barrier (BTB) in mice. Nanostructures were orally administered to adult mice (n = 34). Animals were sacrificed after 3 h, 24 h, 7 d and 14 d following oral administration. Sperm was collected and analysed for viability and kinetic parameters. Collected testes were quantitatively analysed for accumulation of ZnO:Eu NPs. Microscopic evaluation based on immunofluorescence and histopathological studies were also conducted. Results showed that ZnO:Eu NPs were able to overcome the BTB with their subsequent accumulation in the testis. No toxic or pro-apoptotic effects of nanoparticles on the male reproductive system were observed. The results suggested that ZnO:Eu NPs were able to accumulate in the testis with no negative impact on sperm parameters, tissue architecture or the integrity of the BTB.

14-3-3 epsilon plays an important role in testicular germ cell apoptosis: A functional proteomic study of experimental varicocele

The latest perspective indicates that apoptotic dysregulation is an important mechanism in male infertility induced by varicocele. To elucidate the molecular mechanism of apoptosis caused by varicocele, we used proteomics (2D-MALDI-TOF MS) to identify the altered proteins in the testes of experimental varicocele rats compared with the control. Here, 21 significantly different protein spots were detected by proteomics technology. 14-3-3 epsilon (14-3-3ε) was our subsequent research target because of its function in apoptosis. The expression of 14-3-3ε in rat testes was confirmed by Western blot and immunohistochemistry, and the terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) method was used to analyse the apoptosis of germ cells. GC-1 spg cells transfected with small interfering RNA were used to confirm the function of 14-3-3ε in vitro. 14-3-3ε protein expression decreased, accompanied by a higher apoptosis index in rat testes of the varicocele group. Furthermore, 14-3-3ε siRNA-treated GC-1 spg cells caused the upregulation of the apoptotic rate detected by flow cytometry. The expression of Bax and Bcl-2 was found to be regulated by 14-3-3ε in vitro. Our investigation demonstrated the pro-apoptotic function of the downregulation of 14-3-3ε, which may play an important role in germ cell apoptosis induced by varicocele.

An miR-200 Cluster on Chromosome 23 Regulates Sperm Motility in Zebrafish

Besides its well-documented roles in cell proliferation, apoptosis, and carcinogenesis, the function of the p53-microRNA axis has been recently revealed in the reproductive system. Recent studies indicated that miR-200 family members are dysregulated in nonobstructive azoospermia patients, whereas their functions remain poorly documented. The aim of this study was to investigate the function of the miR-200 family on zebrafish testis development and sperm activity. There was no substantial difference in testis morphology and histology between wild-type (WT) and knockout zebrafish with deletion of miR-200 cluster on chromosome 6 (chr6-miR-200-KO) or on chromosome 23 (chr23-miR-200-KO). Interestingly, compared with WT zebrafish, the chr6-miR-200-KO zebrafish had no difference on sperm motility, whereas chr23-miR-200-KO zebrafish showed significantly improved sperm motility. Consistently, ectopic expression of miR-429a, miR-200a, and miR-200b, which are located in the miR-200 cluster on chromosome 23, significantly reduced motility traits of sperm. Several sperm motility-related genes, such as amh, wt1a, and srd5a2b have been confirmed as direct targets of miR-200s on chr23. 17α-ethynylestradiol (EE2) exposure resulted in upregulated expression of p53 and miR-429a in testis and impairment of sperm motility. Strikingly, in p53 mutant zebrafish testis, the expression levels of miR-200s on chr23 were significantly reduced and accompanied by a stimulation of sperm motility. Moreover, the upregulation of miR-429a associated with EE2 treatment was abolished in testis with p53 mutation. And the impairment of sperm activity by EE2 treatment was also eliminated when p53 was mutated. Together, our results reveal that miR-200 cluster on chromosome 23 controls sperm motility in a p53-dependent manner.

Bmi1 Deficient Mice Exhibit Male Infertility

Previous studies have demonstrated that the polycomb repressor Bmi1 is universally expressed in all types of testicular cells and might regulate the spermatogonia proliferation, however, it is unclear whether Bmi1 plays a critical role in maintaining normal male fertility in vivo. To answer this question, we first confirmed that Bmi1 is universally expressed in all types of testicular cells and found that the gene relative expression levels of Bmi1 in testis were the highest relative to other organs. Then we investigated the role of Bmi1 in maintaining normal male fertility using Bmi1 knockout male mouse model. Our results demonstrated that Bmi1 deficiency resulted in totally male infertility with smaller testis, severe oligospermia and sperm malformation. Mechanistically, decreased serum testosterone levels with down-regulating 3βHSD and 17βHSD expression levels, reduced germ cell proliferation, increased germ cell apoptosis with up-regulating p16, p19, p53 and p21 expression levels, increased reactive oxygen species (ROS) and H₂O₂ levels with down-regulating gene expression levels of anti-oxidant enzymes, and increased 8-OHdG and γ.H2AX positive cells in testis were observed in Bmi1 deficient mice compared with wild-type mice. These results indicate that Bmi1 deficiency results in male infertility by reducing testosterone syntheses, increasing oxidative stress and DNA damage, activating p16 and p19 signaling pathway, inhibiting germ cell proliferation and inducing germ cell apoptosis and sperm malformation. Thus, Bmi1 may be a novel and potential target for the clinic treatment of male infertility.

Grape seed proanthocyanidin extract attenuates varicocele‑induced testicular oxidative injury in rats by activating the Nrf2‑antioxidant system

The present study investigated whether grape seed proanthocyanidin extract (GSPE) can attenuate varicocele‑induced testicular oxidative injury through the nuclear factor (erythroid‑derived 2)‑like 2 (Nrf2) antioxidant pathway. A varicocele model in rats was established by partial ligation of the left renal vein. Following 4 weeks of GSPE administration, the decreased sperm count and motility and other pathological changes caused by varicocele were significantly alleviated, as indicated by the results of computer‑assisted sperm analysis and hematoxylin and eosin staining. In addition, the decreased antioxidant enzyme (superoxide dismutase and glutathione peroxidase) activity and elevated oxidative stress level were partially reversed by administration of GSPE. Furthermore, the apoptotic level of the testis induced by varicocele was decreased by the GSPE treatment, according to terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Additionally, the expression of apoptosis‑related proteins, including B‑cell lymphoma 2 (Bcl‑2), Bcl‑2‑like protein 4 and cleaved caspase‑3, were also affected by GSPE. GSPE activated Nrf2, which is a key antioxidative transcription factor, with elevation of the downstream factor hemeoxygenase‑1. These findings suggest that GSPE can ameliorate abnormal spermatogenesis and testicular injury in varicocele rats, potentially due to its antioxidative activity and ability to activate the Nrf2 pathway.

The protective effects of GYY4137 on ipsilateral testicular injury in experimentally varicocele-induced rats

The aim of the present study was to evaluate whether morpholin-4-ium 4 methoxyphenyl (morpholino) phosphonodithioate (GYY4137) exhibits a protective effect on ipsilateral testicular injury in experimentally varicocele (VC)-induced rats. A total of 48 rats were randomly divided into the following 6 groups (n=8 each): Group A (control group); group B (sham group); group C (VC group); group D (VC group administered 5 mg/kg/day GYY4137); group E (VC group administered 10 mg/kg/day GYY4137) and group F (VC group administered 20 mg/kg/day GYY4137). Indicators of oxidative stress, apoptosis and inflammation were measured to evaluate the effect of GYY4137 on ipsilateral testicular injury. Compared with groups A and B, rats in group C exhibited severe histological changes and an increase in oxidative stress, apoptosis and inflammation. By contrast, amelioration of testicular damage was evident in the group D, E and F that were treated with GYY4137. These results demonstrate that GYY4137 may be a promising therapy to treat VC as it alleviates oxidative stress, apoptosis and inflammation in experimentally VC-induced rats.

Bone marrow mesenchymal stem cells repair cadmium-induced rat testis injury by inhibiting mitochondrial apoptosis

Cadmium is a highly toxic metal with widespread exposure to people that can cause tissue injuries that lack effective treatment. The aim of this project was to uncover whether bone marrow mesenchymal stem cells (BMSCs) can repair cadmium-induced rat testis injury and to explore the role of mitochondrial apoptosis in this process. To this end, 21 adult male Wistar rats were randomly divided into control, model and therapy groups, 7 each, and were administered 0, 0.4 and 0.4 mg/kg body weight CdCl₂ saline solution, respectively, by intraperitoneal injection 5 times per week for 5 weeks. Then, rats in the therapy group were treated with 10⁷ BMSCs by retro-orbital injections, while the others were given equal volumes of phosphate buffered saline. Following 2-week BMSCs-treatment, the therapy rats were heavier than the model rats, despite there being no difference in testicular cadmium contents between these groups, which were both significantly higher than the control group. BMSCs were observed in the testis of the therapy rats, in which pathological changes improved significantly compared with the model group. Expression of the apoptosis-associated proteins Bim, Bax, Cytochrome C, Caspase-3, active-Caspase-3 and AIF increased, while Bcl-2 was reduced significantly in rat testes of model group compared with the other groups. Based on these findings, we conclude that cadmium can accumulate in rat testes where it caused severe tissue injury, BMSCs can be localized to the injured testicular tissue of rats and repair the tissue injury, these reparative effects may be highly related with mitochondrial apoptosis.

Role of autophagy in cadmium-induced testicular injury

The testis is sensitive to cadmium, but studies investigating cadmium-induced testicular injury have not yet clearly revealed the underlying mechanisms. This study aimed to investigate the injurious effects of cadmium on rat testes and the role that autophagy plays in this process. Wistar rats were randomly divided into four groups and intraperitoneally injected with 0.2 (low), 0.4 (middle), and 0.8 mg/kg·body weight (high) cadmium chloride for 5 weeks, while the control rats were injected with equal volume of saline. Rats exposed to cadmium appeared inactive and had reduced body weights and increased testicular organ coefficients at the end of treatment compared with control rats. Atomic absorption results showed that cadmium levels increased with increased cadmium exposure. Hematoxylin and eosin staining of testicular sections showed seminiferous tubular atrophy, decreased pipe diameter, spermatogonial stem cells falling off the inner lining, and reduced germ cell layers of disorderly arrangements in cadmium-treated rats. Immunohistochemical and western blot results both showed that levels of the autophagy-related proteins Beclin1 and microtubule-associated protein 1 light chain 3B (LC3B) increased with increased cadmium exposure. We also found that LC3B-II and calcium-sensing receptor (CSR) levels in cadmium-exposed rats significantly increased. By immunofluorescence, we found that the percentage of cells that expressed the CSR was significantly higher in LC3B-positive than LC3B-negative cells. Together, our results showed that cadmium accumulates in the testes causing testicular injury, which may be related to increased autophagy levels. Furthermore, calcium disorders associated with the CSR may reveal a potential way to activate autophagy.