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*

Varicocele (VC) is a common cause of male infertility, yet there is a lack of molecular information for VC-associated male infertility. This study investigated alterations in the seminal plasma metabolomic and lipidomic profiles of infertile male VC patients. Twenty infertile males with VC and twenty-three age-matched healthy controls (HCs) were recruited from Peking Union Medical College Hospital (Beijing, China) between October 2019 and April 2021. Untargeted metabolite and lipid profiles from seminal plasma were analyzed using mass spectrometry. Four hundred and seventy-six metabolites and seventeen lipids were significantly different in infertile male VC patients compared to HCs. The top enriched pathways among these significantly different metabolites are protein digestion and absorption, aminoacyl-transfer RNA (tRNA) biosynthesis, and biosynthesis of amino acids. Different key lipid species, including triglyceride (TG), diacylglycerol (DG), ceramides (Cer), and phosphatidylserine (PS), varied between VC and HC groups. The distinct metabolites and lipids were moderately correlated. DL-3-phenyllactic acid is a potential diagnostic biomarker for VC-related male infertility (area under the curve [AUC] = 0.893), positively correlating with sperm count, concentration, and motility. Furthermore, DL-3-phenyllactic acid is the only metabolite shared by all four comparisons (VC vs HC, VC-induced oligoasthenospermia [OAS] vs VC-induced asthenospermia [AS], OAS vs HC, and AS vs HC). DL-3-phenyllactic acid significantly decreased in OAS than AS. Metabolite-targeting gene analysis revealed carbonic anhydrase 9 (CA9) might be the strongest candidate associated with the onset and severity of VC. The seminal plasma metabolite and lipid profiles of infertile males with VC differ significantly from those of HCs. DL-3-phenyllactic acid could be a promising biomarker.
Humans ; Male ; Varicocele/complications* ; Infertility, Male/etiology* ; Semen/metabolism* ; Lipidomics ; Adult ; Metabolomics ; Case-Control Studies ; Biomarkers/metabolism*

OBJECTIVE: To explore the role of reactive oxygen species (ROS) and lactate dehydrogenase isoenzyme X (LDH-X) in the changes of sperm mitochondrial membrane potential (MMP) in infertility patients with varicocele (VC). METHODS: This study included 38 infertility patients with VC (VCinf), 35 non-VC infertile males (NVCinf), and 30 normal fertile men as controls. We obtained the routine semen parameters using the sperm quality analysis system, examined the contents of LDH-X in the seminal plasma and sperm with the automatic biochemical analyzer, measured the level of malondialdehyde (MDA) in seminal plasma by thiobarbituric acid (TBA) colorimetry, and determined the expressions of mitochondrial membrane potential (MMP) and LDH-X mRNA in the sperm using JC-1 fluorescence probe and RT-PCR. RESULTS: No statistically significant differences were observed among the three groups of subjects in age, semen pH value, semen volume and sperm concentration (P > 0.05). Compared with the normal fertile controls, the patients in the VCinf and NVCinf groups showed significantly decreased sperm motility (［52.36 ± 12.48］% vs ［34.74 ± 15.23］% vs ［25.76 ± 13.73］%, P< 0.05), percentage of progressively motile sperm (PMS) (［42.54 ± 13.58］% vs ［29.10 ± 14.17］% vs ［20.95 ± 12.33］%, P< 0.05), sperm LDH-X (［16.46 ± 5.47］ vs ［13.63 ± 4.50］ vs ［10.18 ± 3.00］ mU/106, P< 0.05), sperm MMP (［48.04 ± 11.62］% vs ［40.86 ± 12.69］% vs ［34.41 ± 13.93］%, P< 0.05) and expression of sperm LDH-X mRNA (P< 0.05). but increased seminal plasma LDH-X (［935.36 ± 229.48］ vs ［1241.05 ± 337.07］ vs ［1425.08 ± 469.35］ U/L, P< 0.05), seminal plasma/whole sperm LDH-X (［1.06 ± 0.35］ vs ［1.40 ± 0.34］ vs ［1.63 ± 0.66］, P< 0.05), and content of seminal plasma MDA (［1.10 ± 0.19］ vs ［1.59 ± 0.27］ vs ［2.00 ± 0.22］ nmol/ml, P< 0.05). CONCLUSION Excessive ROS in the reproductive system of VCinf patients reduces the content of MMP and causes the overflow of LDH-X out of sperm cells. Therefore the decrease of sperm LDH-X may be accompanied by that of MMP.
Humans ; Male ; Infertility, Male/etiology* ; Varicocele/metabolism* ; Adult ; Reactive Oxygen Species/metabolism* ; Spermatozoa/metabolism* ; L-Lactate Dehydrogenase/metabolism* ; Membrane Potential, Mitochondrial ; Isoenzymes/metabolism* ; Case-Control Studies ; Young Adult ; Mitochondrial Membranes/metabolism*

Seminal plasma is a rich source of proteins and serves as an ideal sample for proteomic analysis of male infertility. In varicocele-associated infertility, the contributory role of seminal plasma proteins specific to unilateral and bilateral varicocele is not clear. Furthermore, there is a lack of specific protein biomarker to differentiate bilateral from unilateral varicocele. The main objective is to identify the differentially regulated molecular and cellular pathways in bilateral varicocele. Furthermore, we intend to identify seminal plasma biomarkers to differentiate bilateral and unilateral varicocele patients in comparison with fertile healthy men. Global proteomic analysis of seminal plasma proteins has identified the functionality of differentially expressed proteins (DEPs) in varicocele patients. Bioinformatic analysis has revealed response to reactive oxygen species and oxidative stress, and tissue homeostasis as top process pathways that are affected in bilateral varicocele patients compared to fertile healthy men. In comparison with unilateral varicocele patients, inflammatory response pathways were dysregulated, especially interleukin 6 (IL-6) signaling and Janus kinase-signal transducer and activator of transcription (Jak-STAT) pathways, in bilateral varicocele patients, owing to the involvement of underexpressed DEPs. Key DEPs associated with oxidative stress (peroxiredoxin 2; PRDX2), DNA fragmentation (fatty acid synthase; FASN), and inflammatory response (fibronectin 1; FN1) validated by western blot analysis revealed differential expression of these proteins in unilateral and bilateral varicocele groups. Altered expression of DEPs and its association with key processes show that the seminal plasma homeostasis is compromised in bilateral varicocele patients. Furthermore, we propose PRDX2, FASN, and FN1 as potential noninvasive seminal plasma markers for the differentiation of unilateral and bilateral varicocele patients.
Biomarkers/analysis* ; Blotting, Western ; Humans ; Inflammation/metabolism* ; Male ; Metabolic Networks and Pathways ; Oxidative Stress ; Proteins/analysis* ; Proteomics ; Semen/chemistry* ; Varicocele/metabolism* ; Young Adult

Inhibin B, a glycoprotein produced predominantly by Sertoli cells and preferentially suppressing the production and secretion of follicle-stimulating hormone (FSH) in the pituitary, is closely related to spermatogenesis. Varicocele is the abnormal dilatation and tortuosity of the pampiniform plexus veins, which may contribute to spermatogenic dysfunction and male infertility. More and more evidence has shown that the level of serum inhibin B is negatively correlated with the severity of varicocele. Determination of the inhibin B level may help assess the severity of spermatogenic dysfunction of the patient and predict the outcomes of varicocele repair and therefore has a potential application value in the diagnosis and treatment of varicocele.
Follicle Stimulating Hormone ; metabolism ; Humans ; Infertility, Male ; blood ; etiology ; Inhibins ; blood ; Male ; Sertoli Cells ; Spermatogenesis ; Varicocele ; blood

This study was performed to investigate a potential marker for the presence of spermatozoa in the ejaculate following varicocelectomy in Chinese men with nonobstructive azoospermia and varicoceles. The micro-RNA (miR)-192a levels in seminal plasma and testicular tissue were evaluated by quantitative real-time polymerase chain reaction from 60 men with nonobstructive azoospermia and varicoceles (Group A: 27 men with spermatozoa found in the ejaculate after surgery; Group B: 33 men without spermatozoa found in the ejaculate after surgery) and 30 controls. The seminal plasma and testicular tissue miR-192a levels were higher in Group B than in Group A and the controls (P < 0.001), and there was no significant difference between Group A and the controls (P > 0.05). Apoptosis and proliferation assays with miR mimics and inhibitors showed that miR-192a induced GC-2 cell apoptosis through the activation of Caspase-3 protein. Thus, seminal plasma miR-192a appears to be a potential marker for successfully indicating spermatozoa in the ejaculate following microsurgical varicocelectomy in men with nonobstructive azoospermia and varicoceles. Seminal plasma miR-192a may be a useful clinical marker for prescreening to determine which patients with nonobstructive azoospermia and varicoceles would benefit from varicocelectomy.
Adult ; Apoptosis ; Asian People ; Azoospermia/surgery* ; Biomarkers/analysis* ; Caspase 3/analysis* ; Cell Proliferation ; Humans ; Infertility, Male/etiology* ; Male ; MicroRNAs/biosynthesis* ; Microsurgery ; Predictive Value of Tests ; Semen/metabolism* ; Testis/metabolism* ; Treatment Outcome ; Varicocele/surgery*

Objective: To explore the protective effect of Tongjingling (TJL) against sperm DNA damage and oxidative stress in the rat model of experimental varicocele (EVC). METHODS: We randomly divided 75 Wistar male rats into five groups of equal number: sham operation, EVC model, high-dose TJL, mid-dose TJL, and low-dose TJL. The EVC model was established in the rats by partial ligation of the left renal vein, followed by 8 weeks of medication from the 4th week after modeling. Then we observed the general status of the rats, detected the sperm DNA fragmentation index (DFI) in the epididymis by sperm chromatin structure assay (SCSA), and measured the content of hydroperoxide (H2O2) and the activities of catalase (CAT) and superoxide dismutase (SOD) in the testis by colorimetry. RESULTS: Compared with the sham operation group, the EVC models showed significantly increased sperm DFI in the epididymis (P <0.01) and elevated level of H2O2 and activities of CAT and SOD in the testis (P <0.01). In comparison with the EVC models, the rats of the TJL groups exhibited remarkably reduced sperm DFI and H2O2 content, but increased activities of SOD and CAT. CONCLUSIONS TJL can improve sperm DNA integrity by increasing the activities of SOD and CAT and reducing the H2O2 level and hence oxidative stress in the testis tissue.
Animals ; Catalase ; analysis ; DNA ; drug effects ; DNA Fragmentation ; Drugs, Chinese Herbal ; pharmacology ; Epididymis ; chemistry ; Humans ; Hydrogen Peroxide ; analysis ; Ligation ; Male ; Oxidative Stress ; Random Allocation ; Rats ; Rats, Wistar ; Spermatozoa ; Superoxide Dismutase ; analysis ; Testis ; chemistry ; drug effects ; Varicocele ; etiology ; genetics ; metabolism

ObjectiveTo investigate the relationship of oxidative stress with DNA integrity and semen parameters in infertile men with varicocele (VC).

METHODSThis prospective study included 98 infertile males with VC. According to the levels of reactive oxygen species (ROS) in the semen, we divided the patients into a high ROS group (n=44) and a low ROS group (n=54), determined the sperm DNA fragmentation index (DFI), motility and morphology, and analyzed their correlation with ROS in the two groups of patients.

RESULTSCompared with the patients of the low ROS group, those of the high ROS group showed a significantly higher DFI (27.38±8.10 vs 34.49±6.05, P=0.039) and a higher concentration of seminal leukocytes (［0.65±0.15］×10⁶/ml vs ［0.86±0.41］×10⁶/ml, P=0.022), but lower sperm motility (［36.16±22.83］% vs ［18.22±25.21］%, P=0.017), percentage of progressively motile sperm (［23.34±11.53］% vs ［16.34±9.22］%, P=0.041), sperm curvilinear velocity (［27.03±6.21］ vs ［20.62±4.38］ μm/s, P=0.013), and sperm linearity (［29.75±8.24］% vs ［18.30±7.93］%, P=0.024). Spearman correlation analysis indicated that the ROS level was correlated positively with the concentration of seminal leukocytes (r=0.41, P<0.01) and DFI (r=0.21, P=0.006), but negatively with sperm curvilinear velocity (r=－0.24, P=0.017), linearity (r=－0.24, P=0.021), motility (r=－0.31, P=0.002), and the percentage of progressively motile sperm (r=－0.41, P=0.012). Additionally, the sperm DFI manifested a significant negative correlation with sperm motility (r=－0.29, P<0.01) and the percentage of progressively motile sperm (r=－0.34, P<0.01).

CONCLUSIONSThe level of seminal ROS is positively correlated with the sperm DFI in infertile men with varicocele, and both the ROS level and DNA integrity are associated with semen parameters.

DNA Fragmentation ; Humans ; Infertility, Male ; complications ; Male ; Oxidative Stress ; Prospective Studies ; Reactive Oxygen Species ; metabolism ; Semen ; Sperm Motility ; Spermatozoa ; pathology ; Varicocele ; complications

OBJECTIVETo study the effect of tea polyphenols (TP) on the apoptosis of germ cells in rats with experimental varicocele.

METHODSThirty-two adolescent male Wistar rats were randomly and equally divided into groups A (sham-operation), B (high-dose TP), C (low-dose TP), and D (experimental left varicocele). Experimental varicocele was induced by partial ligation of the left renal vein in the latter three groups of rats. The animals in groups A and D were fed with normal saline, while those in B and C with TP at 40 and 10 mg per kg per d, respectively, all for 4 weeks. Then, all the rats were sacrificed and the left testes harvested for determination of the expression of HIF-1, Bcl-2, Bax, CytC, and caspase-3 by immunohistochemistry and measurement of the apoptosis index (AI) of spermatogenic cells.

RESULTSThe expression of Bcl-2 was higher in groups B and C than in D but lower than in A (P < 0.05), and lower in C than in B (P < 0.05). However, the expressions of HIF-1, Bax, CytC, and caspase-3 were lower in groups B and C than in D but higher than in A (P < 0.05), and higher in C than in B (P < 0.05). The AI of spermatogenic cells was the lowest in group A, higher in D than in the other groups but lower in B than in C (P < 0.05).

CONCLUSIONTP can reduce the apoptosis of spermatogenic cells in a dose-dependent manner in varicocele rats.

Animals ; Apoptosis ; drug effects ; Caspase 3 ; Cytochromes c ; metabolism ; Dose-Response Relationship, Drug ; Hypoxia-Inducible Factor 1, alpha Subunit ; metabolism ; Ligation ; Male ; Polyphenols ; administration & dosage ; pharmacology ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Random Allocation ; Rats ; Rats, Wistar ; Renal Veins ; Spermatozoa ; drug effects ; Tea ; chemistry ; Testis ; metabolism ; Varicocele ; complications ; metabolism ; bcl-2-Associated X Protein ; metabolism

OBJECTIVETo investigate the influence of varicocele (VC) on semen parameters and the concentration of inhibin B in the serum and seminal plasma of VC men.

METHODSWe collected semen and peripheral blood samples from 95 infertile VC patients and 55 normal fertile men. We performed semen routine examination by computer-assisted semen analysis and sperm morphology examination by modified Papanicolaou staining, and measured the levels of inhibin B in the peripheral blood and seminal plasma of the subjects by ELISA.

RESULTSCompared with the normal fertile controls, the infertile men with grade-I, -II and -III VC showed significantly lower percentages of morphologically normal sperm ([7.5 +/- 5.2]% vs [6.3 +/- 6.5]%, [2.6 +/- 3.0]% and [1.0 +/- 0.7]%, P < 0.05) and progressively motile sperm ([43.9 +/- 22.7]% vs [33.3 +/- 20.8]%, [28.9 +/- 19.8]% and [13.5 +/- 8.4]%, P < 0.05). The majority of the morphologically abnormal sperm were of the type of head deformity. The concentrations of inhibin B in the peripheral blood and seminal plasma were evidently lower in the infertile men with grade-I VC ([160.9 +/- 48.9] pg/ml and [208.3 +/- 28.1] pg/ml), grade-II VC ([150.6 +/- 44.7] pg/ml and [201.5 +/- 83.5] pg/ml), and grade-III VC ([132.6 +/- 41.5] pg/ml and [150.2 +/- 51.6] pg/ml) in comparison with those of the fertile control group ([201.0 +/- 38.1] pg/ml and [225.3 +/- 82.5] pg/ml).

CONCLUSIONVaricocele reduces sperm motility, increases sperm abnormality, decreases the concentration of inhibin B in the serum and seminal plasma, and consequently damages male fertility.

Adult ; Case-Control Studies ; Humans ; Infertility, Male ; physiopathology ; Inhibins ; blood ; metabolism ; Male ; Semen ; cytology ; metabolism ; Semen Analysis ; Sperm Motility ; Varicocele ; blood ; metabolism