Roles of Fas/FasL-mediated apoptosis and inhibin B in the testicular dysfunction of rats with left-side varicocele

Differential Impairment Mechanism of Sperm Production via Induction of miR-34c-Activated Apoptosis and Spermatogenesis Pathway in Diet-Induced Obesity and Resistant Mice and GC-1 Spg Cells

Male reproductive dysfunction is a clinical disease, with a large number of cases being idiopathic. Reproductive disorders have been found in obese (diet-induced obesity and diet-induced obesity-resistant) mice, but the mechanism behind the male reproductive dysfunction between them may be different. The purpose of this study was to explore the possible role and mechanism of miR-34c on sperm production in high-fat-diet-induced obesity-resistant (DIO-R) mice and GC-1 spg cells, which may differ from those in high-fat-diet-induced obesity (DIO) mice. In vivo and in vitro experiments were performed. C57BL/6J mice were fed a high-fat diet for 10 weeks to establish the DIO and DIO-R mouse model. GC-1 spg cells were used to verify the mechanism of miR-34c on sperm production. During in vivo experiments, sperm production damage was found in both DIO and DIO-R male mice. Compared to the control mice, significantly decreased levels of testosterone, LH, activities of acrosome enzyme (ACE), HAse, and activating transcription factor 1 (ATF1) were found in both DIO and DIO-R male mice (p < 0.05). Compared with the control group, the ratio of B-cell lymphoma-2 (Bcl-2)/bcl-2-associated X protein (Bax) in the DIO group was significantly decreased, and the expression level of cleaved caspase-3 was significantly increased (p < 0.05). Compared with the control group, the Bcl-2 protein expression level in the testes of the DIO-R group significantly decreased (p < 0.05). However, the Bax expression level increased. Thus, the Bcl-2/Bax ratio significantly decreased (p < 0.01); however, the factor-related apoptosis (Fas), Fas ligand (FasLG), cleaved caspase-8, caspase-8, cleaved caspase-3, and caspase-3 protein expression levels significantly increased (p < 0.05). Compared with the DIO group, in DIO-R mice, the activities of ACE, ATF1, Bcl-2, and Bcl-2/Bax's spermatogenesis protein expression decreased, while the apoptosis-promoting protein expression significantly increased (p < 0.05). During the in vitro experiment, the late and early apoptotic ratio in the miR-34c over-expression group increased. MiR-34c over-expression enhanced the expression of apoptosis-related proteins Fas/FasLG and Bax/Bcl-2 while inhibiting the expression of ATF1 and the sperm-associated protein in GC-1 spg cells. DIO and DIO-R could harm sperm production. DIO-R could impair sperm production by inducing the miR-34c-activated apoptosis and spermatogenesis pathway, which may be different from that of DIO.

Mechanism of 2,4-Dichlorophenoxyacetic acid-induced damage to rat testis via Fas/FasL pathway and the protective effect of Lycium barbarum polysaccharides

The herbicide 2,4-Dichlorophenoxyacetic acid (2,4-D) is widely used to control broadleaved weeds and has been associated with male infertility. We studied the molecular mechanisms of 2,4-D induced male reproductive system damage and the protective effects of Lycium barbarum polysaccharides (LBP) using Sprague Dawley rats and TM4 cells. Treatment with 2,4-D caused architectural and functional changes in the testis, including collapsed and atrophied seminiferous tubules with reduced number of spermatozoa, scarce sperm in the epididymal duct, low levels of serum testosterone, decreased superoxide dismutase and glutathione peroxidase activity, high malondialdehyde content, and increased apoptosis in the testis and epididymis. The expression of Fas, FasL, FADD, Pro-caspase-8, Cleaved-Caspase-8, Pro-Caspase-3, and Cleaved-Caspase-3 were significantly increased in the testicular tissue of 2,4-D-treated rats. The proliferative activity of TM4 cells decreased with an increase in dose and time of 2,4-D exposure, along with enhanced Fas/Fas ligand expression and a decreased concentration of inhibin B in TM4 cell culture medium. Depletion of Fas by specific shRNA transfection reversed the effects of 2,4-D in TM4 cells, further confirming the involvement of death receptor pathway in 2,4-D-mediated apoptosis of sertoli cells. Treatment with LBP also reversed the effects of 2,4-D in testicular cells, resulting in improved cell architecture along with enhanced proliferative capacity. Moreover, in response to LBP treatment of Sertoli cells, the content of inhibin B increased, the level of reactive oxygen species and malondialdehyde decreased, the activities of superoxide dismutase and glutathione peroxidase increased, and the rate of apoptosis as well as the expression of Fas/Fas ligand signaling pathway proteins decreased.

Maternal exposure to PM2.5 disrupting offspring spermatogenesis through induced sertoli cells apoptosis via inhibin B hypermethylation in mice

Particulate Matter 2.5 (PM_2.5) disrupts endocrine functions and may negatively affect sperm quality and quantity in males; however, the long-term effects and potential mechanisms of this effect are unknown. This study aimed to investigate the epigenetic mechanism of maternal exposure to PM_2.5-induced inhibin B hypermethylation in male offspring. In this experiment design, pregnant C57BL/6 mice were treated with two doses of PM_2.5 (4.8 and 43.2 mg/kg bw). The membrane control group was given a sampling membrane and the control group received nothing. Following the formation of the vaginal plug, intratracheal instillation of PM_2.5 was administered every three days until delivery of the pups. To assess the effect of PM_2.5 in vitro, TM4 cells, a Sertoli-like cell line, was treated with different concentrations (0, 25, 50, 100 μg/mL) of PM_2.5 for 24 h. The results displayed that Sperm motility, as well as the number of adult offspring, was decreased in the PM_2.5 exposed group relative to the untreated controls. Increased vacuolization was observed in the Sertoli cells of mice that were exposed to PM_2.5 in utero. The levels of inhibin and testosterone were reduced and the levels of LH and FSH increased in the PM_2.5 groups relative to the untreated controls. In vitro, PM_2.5 resulted in cell cycle inhibition as well as increased apoptosis in TM4 cells. Moreover, PM_2.5-induced inhibin B hypermethylation and activation of the p21/Cleaved Caspase-3 pathway resulted in TM4 cell apoptosis that was rescued through the use of a DNA methylation inhibitor. Together, our data suggest that prenatal exposure to PM_2.5 results in inhibin B hypermethylation and can activate the p21/Cleaved Caspase-3 pathway, resulting in Sertoli cell apoptosis, aberrant secretion of androgen binding protein, and decreased testosterone, thus resulting in the inhibition of spermatogenesis.

The effect of Fumaria parviflora on the expression of sexual hormones along with their receptors in testicles of adult rats induced by varicocele

Varicocele (VCL) is a pathological dilation of the venous pampiniform plexus of the spermatic cord and is also classified as male factor infertility. The current experiment aimed to examine the protective effect of Fumaria parviflora (FP), as a powerful antioxidant, against reproductive damage induced by VCL. In this experimental study, 32 male rats were randomly allocated into four groups, namely sham (simple laparotomy without additional intervention), FP (healthy rats administered 250 mg/kg FP), VCL + FP (underwent VCL and received 250 mg/kg FP), VCL (underwent VCL without receiving any treatment). The results showed that the number of Sertoli and germ cells were markedly reduced in the VCL group in comparison to the FP-treated and sham groups. The VCl + FP group had significantly higher serum levels of testosterone (T), FSH, and LH hormones than the VCL group. The quality and motility of spermatozoa were reduced in the VCL group compared with other groups (p ≤ 0.05). Moreover, our findings demonstrated that the administration of FP considerably enhanced the mRNA levels of CatSper-1 and -2, SF-1, 3β-HSD, 17β-HSD3, LHCGR, and FSHR (p ≤ 0.05). Based on the obtained results, treatment with FP is capable of preventing testicular dysfunction and elevating the concentration of hormones and some crucial genes, such as CatSper1 and 2, SF-1, 3β-HSD, 17β-HSD3, LHCGR, and FSHR that contribute to the spermatogenesis process.

Melatonin epigenetic potential on testicular functions and fertility profile in varicocele rat model is mediated by Silent information regulator1

BACKGROUND AND PURPOSE

Varicocele is a leading cause of male infertility. Melatonin is a highly pleiotropic neurohormone. We aimed to characterize the melatonin epigenetic potential in varicocele and the involved molecular mechanisms.

EXPERIMENTAL APPROACH

Fifty-two male albino rats were randomly divided into four groups (13 rats each): control (I), melatonin (II), varicocele (III) and melatonin treated varicocele (IV) groups. Left varicocele was induced by partial left renal vein ligation. Reproductive hormones, epididymal sperm functional parameters, testicular 3/17 β-hydroxysteroid dehydrogenases, antioxidant enzymes, malondialdehyde, nicotinamide adenine dinucleotide phosphate oxidase, 8-hydroxy-2'-deoxyguanosine and histopathological/Johnsen's score were evaluated. Flow cytometry and Comet were carried out to explore extent of sperm and testicular DNA damage. Testicular expression of silent information regulator 1 (SIRT1), forkhead transcription factors-class O (type1) (FOXO1), tumour suppressor gene, P53, cation channels of sperm (CatSper) and steroidogenic acute regulatory protein was evaluated by western blot technique. Testicular expression of Bcl-2 and its associated X protein and nuclear factor kappa-light-chain-enhancer of activated B cells were assayed by immunohistochemical staining. Testicular miR-34a expression was quantified by quantitative reverse transcription-polymerase chain reaction.

KEY RESULTS

The varicocele induced testicular histological injury, enhanced oxidative stress, P53-mediated apoptosis, DNA damage and increased testicular miR-34a expression paralleled with down-regulated SIRT1/FOXO axis. Melatonin treatment of varicocele rats displayed antioxidant/anti-apoptotic efficacy and improved reproductive hormones axis, CatSper expression and fertility parameters. MiR-34a/SIRT1/FOXO1 epigenetic axis integrates testicular melatonin mediated intracellular transduction cascades in varicocele.

CONCLUSION AND IMPLICATIONS

Melatonin can be used as an adjuvant therapy to improve varicocele and its complication.

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.

Comparison of the clinical characteristics of patients with varicocele according to the presence or absence of scrotal pain

We investigated the clinical characteristics of patients with varicocele according to the presence or absence of scrotal pain. We retrospectively reviewed the records of patients who underwent varicocelectomy. The age, body mass index, grade, laterality of varicocele, testicular volume difference, time to hospital visit, serum testosterone level and semen parameters were evaluated. A total of 954 patients were included. The painful group had lower mean age, lower BMI, higher grade of varicocele, smaller testicular volume difference and shorter time to hospital visit than the painless group. In addition, the median serum total testosterone level and total sperm count, concentration and motility were higher in the painful group than in the painless group. In multivariate analysis, there were significant differences between the two groups in age, grade of varicocele, testis volume difference, time to hospital visit, total sperm count and concentration. Patients with painful varicocele visited hospital earlier because of the pain and tended to start treatment sooner. They were also younger, had smaller testis atrophy and had higher sperm concentration, even though they had a higher grade of varicocele than patients without pain. Although scrotal pain in varicocele patients is difficult to treat, it leads to early diagnosis and treatment.