Recently, male reproductive health has attracted extensive attention, with the adverse effects of circadian disruption on male fertility gradually gaining recognition. However, the mechanism by which circadian disruption leads to damage to male reproductive system remains unclear. In this review, we first summarized the dual regulatory roles of circadian clock genes on the male reproductive system: (1) circadian regulation of testosterone synthesis via the hypothalamic-pituitary-testicular (HPT) and hypothalamic-pituitary-adrenal (HPA) axes; (2) non-circadian regulation of spermatogenesis. Next, we further listed the possible mechanisms by which circadian disruption impairs male fertility, including interference with the oscillatory function of the reproductive system, i.e., synchronization of the HPT axis, crosstalk between the HPT axis and the HPA axis, as well as direct damage to germ cells by disturbing the non-oscillatory function of the reproductive system. Future research using spatiotemporal omics, epigenomic assays, and neural circuit mapping in studying the male reproductive system may provide new clues to systematically unravel the mechanisms by which circadian disruption affects male reproductive system through circadian clock genes.
Male ; Humans ; Animals ; Circadian Clocks/physiology* ; Hypothalamo-Hypophyseal System/physiology* ; Circadian Rhythm/genetics* ; Spermatogenesis/physiology* ; Pituitary-Adrenal System/physiology* ; Testis/physiology* ; Testosterone/biosynthesis* ; CLOCK Proteins ; Infertility, Male/physiopathology*

Varicocele, the most common and treatable cause of male infertility, significantly impacts fertility. The pathophysiological mechanisms of varicocele have not been fully understood yet. Recent studies have focused on the pathophysiology of varicocele-induced infertility, highlighting inflammation and oxidative stress as key contributing factors. We reviewed recent research on the roles of inflammation and oxidative stress in the pathophysiology of varicocele and found that they negatively impact semen parameters, spermatogenesis, and testicular and epididymal function. In addition, this article summarizes the related factors of inflammation and oxidative stress caused by varicocele. Finally, a brief consideration on the treatments to address inflammation and oxidative stress is proposed. This review may provide treatment options and targets for varicocele-induced infertility. However, the relationship between inflammation and oxidative stress in varicocele still needs further study.
Varicocele/physiopathology* ; Humans ; Oxidative Stress/physiology* ; Infertility, Male/metabolism* ; Male ; Inflammation/physiopathology* ; Spermatogenesis/physiology*

A growing global trend indicates a decline in semen quality, with a lack of physical activity identified as one of the contributing factors. Exercise is medication, and numerous studies have explored its effects on semen quality. However, there is no consensus on the most effective type and intensity of exercise for improving semen quality, owing to inconsistent findings across studies. These discrepancies may be attributable to variations in study populations ( e.g. , healthy versus infertile individuals) and research methodologies ( e.g., observational versus interventional studies). This paper reviews the existing literature from the databases PubMed, Web of Science, and Google Scholar, reclassifying articles on their subject and research designs to delineate the relationship between exercise and semen quality. It also summarizes the mechanisms through which exercise influences semen quality, including hormonal regulation, oxidative stress, and inflammatory factors.
Humans ; Semen Analysis ; Male ; Exercise/physiology* ; Oxidative Stress/physiology* ; Infertility, Male/physiopathology* ; Sperm Motility/physiology*

The adverse effects of obesity on male reproductive function are mainly manifested as the abnormal development of the reproductive system, decrease of testosterone level, decline of sperm quality, and impact on the health of offspring, while its regulatory mechanism is far from being clarified. This paper expounds the influence of obesity on the male reproductive system in the aspects of population epidemiology and animal experiments, presents an overview on the action mechanisms of obesity from the perspectives of the hypothalamus-pituitary-testis axis, blood-testis barrier, inflammatory reaction, oxidative stress, testicular germ cell apoptosis, and impact of paternal obesity on the health of offspring, aiming to shed some light on the clinical treatment and prevention of obesity-related male reproductive dysfunction.
Male ; Obesity/physiopathology* ; Humans ; Animals ; Hypothalamo-Hypophyseal System ; Testis/physiopathology* ; Oxidative Stress ; Infertility, Male/etiology* ; Reproduction ; Blood-Testis Barrier

BACKGROUND: The industrial revolution has resulted in increased synthesis and the introduction of a variety of compounds into the environment and their potentially hazardous effects have been observed in the biota. The present study was aimed to evaluate the potential endocrine-disrupting effects of chronic exposure to the low concentrations of bisphenol S (BPS) in male rats. METHODS: Weaning male Sprague-Dawley rats (22 days old) were either exposed to water containing 0.1% ethanol for control or different concentrations of BPS (0.5, 5, and 50 μg/L) in drinking water for 48 weeks in the chronic exposure study. After completion of the experimental period, animals were dissected and different parameters (hormone concentrations, histology of testis and epididymis, oxidative stress and level of antioxidant enzymes in the testis, daily sperm production (DSP), and sperm parameters) were determined. RESULTS: Results of the present study showed a significant alteration in the gonadosomatic index (GSI) and relative reproductive organ weights. Oxidative stress in the testis was significantly elevated while sperm motility, daily sperm production, and the number of sperm in epididymis were reduced. Plasma testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) concentrations were reduced and estradiol levels were high in the 50 μg/L-exposed group. Histological observations involved a significant reduction in the epithelial height of the testis along with disrupted spermatogenesis, an empty lumen of the seminiferous tubules, and the caput region of the epididymis. CONCLUSION These results suggest that exposure to 5 and 50 μg/L of BPS for the chronic duration started from an early age can induce structural changes in testicular tissue architecture and endocrine alterations in the male reproductive system which may lead to infertility in males.
Animals ; Biomarkers ; Endocrine Disruptors/toxicity* ; Environmental Exposure/adverse effects* ; Environmental Pollutants/toxicity* ; Hypothalamo-Hypophyseal System/physiopathology* ; Infertility, Male/physiopathology* ; Male ; Phenols/toxicity* ; Rats ; Rats, Sprague-Dawley ; Sulfones/toxicity* ; Testis/physiopathology* ; Toxicity Tests, Chronic

Leptin, an adipocyte-derived hormone, serves numerous physiological functions in the body, particularly during puberty and reproduction. The exact mechanism by which leptin activates the gonadotropin-releasing hormone (GnRH) neurons to trigger puberty and reproduction remains unclear. Given the widespread distribution of leptin receptors in the body, both central and peripheral mechanisms involving the hypothalamic-pituitary-gonadal axis have been hypothesized. Leptin is necessary for normal reproductive function, but when present in excess, it can have detrimental effects on the male reproductive system. Human and animal studies point to leptin as a link between infertility and obesity, a suggestion that is corroborated by findings of low sperm count, increased sperm abnormalities, oxidative stress, and increased leptin levels in obese men. In addition, daily leptin administration to normal-weight rats has been shown to result in similar abnormalities in sperm parameters. The major pathways causing these abnormalities remain unidentified; however, these adverse effects have been attributed to leptin-induced increased oxidative stress because they are prevented by concurrently administering melatonin. Studies on leptin and its impact on sperm function are highly relevant in understanding and managing male infertility, particularly in overweight and obese men.
Animals ; Humans ; Infertility, Male/physiopathology* ; Leptin/physiology* ; Male ; Obesity/complications* ; Overweight/complications* ; Reproduction/physiology*

ObjectiveTo explore Mycoplasma genitalium (MG) infection in the urogenital tract of infertile men and its influence on semen quality.

METHODSSemen samples were collected from 352 infertile males in the Center of Reproductive Medicine of Nanjing General Hospital from March to July 2015. MG infection was detected by real-time fluorescence simultaneous amplification and testing and semen analyses were conducted according to the WHO Laboratory Manual for the Examination and Processing of Human Semen (5th Ed) on the semen pH value, semen volume, total sperm count, sperm concentration, total sperm motility, percentages of progressively motile sperm (PMS) and immotile sperm (IMS), and sperm DNA fragmentation index (DFI). The data obtained were subjected to statistical analysis by t-test and non-parametric test (Wilcoxon test).

RESULTSMG infection was found in 3.4% (12/352) of the infertile patients. Compared with the MG-positive cases, the MG-negative ones showed a significantly higher semen volume (［2.85 ± 0.14］ vs ［3.84 ± 0.12］ ml, P = 0.008) and percentage of PMS (［15.86±1.72］ vs ［60.95 ± 5.63］ %, P = 0.032) but a lower DFI (［30.73 ±2.24］ vs ［20.71 ± 1.55］%, P = 0.014). However, no statistically significant differences were observed between the two groups in the semen pH value (7.38 ±0.02 vs 7.39 ± 0.01, P = 0.774), sperm concentration (［52.96 ± 15.78］ vs ［60.05 ± 4.29］×10⁶/ml, P = 0.683), sperm count (［154.15 ± 46.37］ vs ［221.56 ± 15.43］×106, P = 0.236), total sperm motility (［29.04 ± 3.11］ vs ［33.52 ± 1.51］ %, P = 0.626), or percentage of IMS (［23.57 ± 0.99］ vs ［62.34 ± 1.69］ %, P = 0.691).

CONCLUSIONSUrogenital MG infection is common in infertile males and potentially affects the semen quality, especially sperm vitality of the patient.

DNA Fragmentation ; Humans ; Infertility, Male ; microbiology ; physiopathology ; Male ; Male Urogenital Diseases ; microbiology ; Mycoplasma Infections ; complications ; Mycoplasma genitalium ; Semen ; Semen Analysis ; Sperm Count ; Sperm Motility ; Spermatozoa ; physiology

The impact of acupuncture for the pregnancy of in vitro fertilization-embryo transfer (IVF-ET) is discussed in the paper. Nowadays there are various conclusions about the impact of acupuncture for IVF-ET, and it may result from the differences in research designs. The effect is closely related to the demographic and clinical characteristics of subjects, such as age, the diagnosis of barrenness, blood flow index of uterine spiral arteries, the cycle of IVF, etc. Besides, the efficacy is influenced by treatment based on syndrome differentiation or not, the frequency and course of acupuncture in both the treating group and the control group, etc. If more reasonable design is achieved in the further study based on them, more reliable evidence will be provided for the effect and mechanism of the pregnancy of IVF-EF by acupuncture.
Acupuncture Therapy ; Embryo Transfer ; Female ; Fertilization in Vitro ; Humans ; Infertility, Female ; physiopathology ; therapy ; Male ; Pregnancy ; Pregnancy Rate ; Randomized Controlled Trials as Topic ; Treatment Outcome

Prolactin is a polypeptide hormone which mainly acts on the reproductive system and plays an important role in penile erection and ejaculation. Prolactin receptors have a variety of short forms apart from the classic long form, which are widely expressed in male reproductive glands. High levels of prolactin can induce erectile dysfunction and results in secondary male infertility, which are mainly associated with the inhibition of dopaminergic activity, reduction of the testosterone level, and contraction of the cavernous smooth muscle. Moreover, low levels of prolactin can result in ejaculatory dysfunction. This article updates the views on the expressions of prolactin receptors in the male reproductive system, the effects of prolactin on penile erection and ejaculation, and its action mechanisms.
Ejaculation ; physiology ; Erectile Dysfunction ; Humans ; Infertility, Male ; Male ; Muscle, Smooth ; physiopathology ; Penile Erection ; physiology ; Prolactin ; physiology ; Receptors, Prolactin ; physiology ; Reproduction

OBJECTIVETo investigate the association of male reproductive tract infection (RTI) with semen parameters and sperm DNA damage.

METHODSWe classified 1 084 males attending the infertility clinic into an RTI group (n = 300) and a non-RTI control group (n = 784). According to the WHO standards, we obtained routine semen parameters, detected sperm morphology, and determined the sperm DNA fragmentation index (DFI) by sperm chromatin structure assay.

RESULTSThere were statistically significant differences between the RTI and control groups in the semen volume ( [2.58 ± 1.20] vs [3.00 ± 2.10] ml), grade a + b sperm ([50.6 ± 17.2] vs [53.2 ± 15.8]%), grade d sperm ( [39. 8 ± 17.8] vs [36.5 ± 16.2]%), and total sperm count ([218.5 ± 185.0 ] vs [278.5 ± 375.5 ] x 10(6)/ejaculate) (all P < 0.05), but not in the males' age, sperm concentration or pH value (P > 0.05). The percentage of morphologically normal sperm was significantly lower ([3.46 ± 2.90] vs [4.61 ± 3.60%, P < 0.05) but the DFI was markedly higher in the RTI group than in the control ([19.4 ± 11.4] vs [15.2 ± 8.8]% , P < 0.01). The percentage of the cases with DFI > 30% was remarkably higher (13.0 vs 5.74% ) while that of the cases with DFI < 10% dramatically lower in the former than in the latter (16.0 vs 28.0%). The level of seminal plasma elastase was correlated negatively to sperm concentration, sperm count, and the percentage of morphologically normal sperm (P < 0.05) but positively to DFI and grade d sperm (P < 0.05 or P < 0.01).

CONCLUSIONMale reproductive tract infection not only affects semen parameters and sperm morphology but also causes serious sperm DNA damage.

DNA Fragmentation ; Humans ; Infertility, Male ; physiopathology ; Male ; Reproductive Tract Infections ; physiopathology ; Semen ; chemistry ; Semen Analysis ; Sperm Count ; Spermatozoa ; pathology