Explore the vast range of titles available.

Varicocele (VC) is present in 35 - 40% of men with infertility. However, current surgical and antioxidant treatments are not completely effective. In addition to oxidative stress, it is likely that other factors such as testicular immune microenvironment disorder contribute to irreversible testicular. Evidence suggests that VC is associated with anti-sperm antibodies (ASAs), spermatogenesis and testosterone secretion abnormalities, and testicular cytokine production. Moreover, inhibition of inflammation can alleviate VC-mediated pathogenesis. The normal function of the testis depends on its immune tolerance mechanism. Testicular immune regulation is complex, and many infectious or non-infectious diseases may damage this precision system. The testicular immune microenvironment is composed of common immune cells and other cells involved in testicular immunity. The former includes testicular macrophages, T cells, dendritic cells (DCs), and mast cells, whereas the latter include Leydig cells and Sertoli cells (SCs). In animal models and in patients with VC, most studies have revealed an abnormal increase in the levels of ASAs and pro-inflammatory cytokines such as interleukin (IL)-1 and tumor necrosis factor (TNF)-alpha in the seminal plasma, testicular tissue, and even peripheral blood. It is also involved in the activation of potential inflammatory pathways, such as the nucleotide-binding oligomerization domain-like receptor family pyrin domain containing (NLRP)-3 pathway. Finally, the development of VC-mediated infertility (VMI) may be facilitated by abnormal permeability of proteins, such as claudin-11, that constitute the blood-testis barrier (BTB). The testicular immune response, including the production of ASAs and inflammatory factors, activation of inflammatory pathways, and destruction of the BTB may be involved in the pathogenesis of VMI it is necessary to further explore how patient outcomes can be improved through immunotherapy.

Bacterial infections, particularly uropathogenic E. coli (UPEC), contribute substantially to male infertility through tissue damage and subsequent fibrosis in the testis and epididymis. The role of testicular macrophages (TMs), a diverse cell population integral to tissue maintenance and immune balance, in fibrosis is not fully understood. Here, we used single-cell RNA sequencing in a murine model of epididymo-orchitis to analyze TM dynamics during UPEC infection. Our study identified a marked increase in S100a4+ macrophages, originating from monocytes, strongly associated with fibrotic changes. This association was validated in human testicular and epididymal samples. We further demonstrated that S100a4+ macrophages transition to a myofibroblast-like phenotype, producing extracellular matrix proteins such as collagen I and fibronectin. S100a4, both extracellular and intracellular, activated collagen synthesis through the TGF-β/STAT3 signaling pathway, highlighting this pathway as a therapeutic target. Inhibition of S100a4 with niclosamide or macrophage-specific S100a4 KO markedly reduced immune infiltration, tissue damage, and fibrosis in infected murine models. Our findings establish the critical role of S100a4+ macrophages in fibrosis during UPEC-induced epididymo-orchitis and propose them as potential targets for antifibrotic therapy development.

Infection-induced orchitis, a leading cause of acquired male infertility affecting 8%-12% of couples globally, is driven by unresolved inflammatory responses following bacterial infection. We employed uropathogenic (UPEC)- and lipopolysaccharide (LPS)-induced orchitis models to define the mechanisms underlying testicular inflammation. We interrogated the cellular sources of CXCL9/CXCL10 and assessed macrophage-driven inflammatory cell recruitment and spermatogenic disruption. Mechanistic studies were focused on lysine lactylation, STAT1 protein stability, ubiquitin-proteasome-mediated degradation, and the role of the E3 ubiquitin ligase TRIM21. We demonstrate that macrophages are the predominant source of CXCL9 and CXCL10 responsible for recruiting inflammatory cells into the testis, thereby disrupting spermatogenesis. Mechanistically, the lysine lactylation in macrophages promotes STAT1-mediated CXCL9 and CXCL10 expression by inhibiting ubiquitin-proteasome pathway-mediated STAT1 degradation. Specifically, K345 lactylation of the E3 ubiquitin ligase TRIM21 attenuates ubiquitin-proteasome pathway-mediated STAT1 degradation in macrophages by preventing its interaction with STAT1. This study provides the first evidence that non-histone lactylation (TRIM21 K345) exacerbates inflammatory orchitis and highlights TRIM21 lactylation or CXCL9/10 as promising therapeutic targets for infection-associated male infertility.

Acquired infertility due to chronic asymptomatic orchitis (CAO) is a common finding in male dogs. It is characterized by spermatogenic arrest, a significant reduction in spermatogonia, immune cell infiltration and a disruption of the blood–testis barrier. Sertoli cells are a key factor for spermatogenesis and the testicular micromilieu. We hypothesize altered Sertoli cell function to be involved in the pathogenesis of canine CAO. Consequently, the aim was to gain further insights into the spermatogonial stem cell niche and Sertoli cell function in CAO-affected dogs. Therefore, the testicular expression of the Sertoli cell-derived factors bFGF, GDNF, WNT5A, BMP4, CXCL12 and LDHC were evaluated in 15 CAO testis tissues and 10 normospermic controls by relative quantitative real-time PCR (qPCR). Additionally, the protein expression patterns of bFGF, GDNF and WNT5A were visualized immunohistochemically (IHC). This study revealed an overexpression of bFGF (IHC, p < 0.0001), GDNF (qPCR, p = 0.0036), WNT5A (IHC, p = 0.0066) and CXCL12 (qPCR, p = 0.0003) and a reduction in BMP4 (qPCR, p = 0.0041) and LDHC (qPCR, p = 0.0003) in CAO-affected testis in dogs, clearly confirming impaired Sertoli cell function in canine CAO. Sertoli cell function is essential for spermatogenesis and must be considered for potential therapeutic approaches.

In order to clarify injure mechanism of busulfan to spermatogenic function, we treated mice with busulfan, the testicular and epididymal weights and sperm concentration significantly decreased and the sperm malformation rate increased over time. Moreover, testicular interstitial cell infiltration, a smaller seminiferous tubule, and disorganized and shed spermatogenic cells were also observed by immunohistochemical, immunofluorescence detection after the busulfan treatment. Furthermore, the enzyme-linked absorbance assays showed serum interleukin (IL)-6, IL-1β, and tumor necrosis factor-apha levels (inflammatory factors) were significantly upregulated; blood-testis barrier (BTB)-related protein levels (e.g., N-Cadherin, occludin, and connexin 43) and vimentine gradually decreased. So we infer busulfan treatment induced orchitis, further disrupted the BTB and disrupted the spermatogenic microenvironment, then decreased vimentine and gradually damaged the cytoskeleton, which cause spermatogenic cells losing their supporting from sertoli cells, androgen regulation was also affected, which was detrimental to spermatogenesis. The study result will improve the efficiency and safety in spermatogonial stem cell transplant recipients.

Background Phthalates such as di (2-ethylhexyl) phthalate (DEHP) are well known exogenous substances, disrupting reproductive system function and structure. The current research demonstrated the effect of ellagic acid (EA) on DEHP-induced testicular injury in mice. Methods Thirty-five healthy adult male mice were randomly divided to five groups; normal saline receiving group, DEHP (2 g/kg/day, dissolved in corn oil, p.o.) receiving group, DEHP (2 g/kg/day, dissolved in corn oil, p.o.) and EA receiving groups (25, 50 and 100 mg/kg/day, p.o.). Treatment duration of animals was 14 days. Body and testes weights and sperm characteristics and histological changes of testes were evaluated. Serum testosterone, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels were analyzed. In the testicular tissue, oxidative/nitrosative stress markers and inflammatory cytokine levels were measured. Results Ellagic acid significantly reduced DEHP-induced reduction of body and testes weights. The DEHP-induced reduction of spermatogonia, primary spermatocyte and sertoli cells numbers as well as reduction of sperm vitality and progressive motility were reversed by EA. Furthermore, EA inhibited DEHP-induced alterations in serum hormone levels. These effects were associated with the reduction of DEHP-induced increased level of oxidative stress and inflammatory responses. Conclusions Ellagic acid considerably inhibits testicular toxicity of DEHP through reducing oxidative/nitrosative stress and inflammatory responses. Our data suggest that EA may be considered as a promising agent to inhibit male reproductive toxicity induced by endocrine disrupting chemicals such as DEHP.

Orchitis, an inflammation of the testes primarily caused by viral infections such as mumps, presents a significant threat to male reproductive health. This study explores the role of Src homology 2 (SH2)-containing tyrosine phosphatase-1 (SHP-1), a known tumor suppressor, in mitigating inflammation and apoptosis in testicular cells within a model of viral-induced orchitis. To simulate the immune response associated with viral orchitis, we utilized Poly (I:C) , a synthetic analog of double-stranded RNA, which mimics the molecular patterns of viral RNA. This model provides a relevant framework for investigating immune responses in the testes triggered by viral-like stimuli. Our research aimed to elucidate the impact of SHP-1 expression on the inflammatory and apoptotic pathways activated during testicular inflammation. We found that Poly (I:C) induced significant inflammation and apoptosis in Leydig and Sertoli cells, characterized by reduced SHP-1 expression and elevated phosphorylated-STAT3 levels. Enhancing SHP-1 expression attenuated these inflammatory and apoptotic responses, whereas reactivating STAT3 with colivelin reversed the suppression of cytokine production and cell death. Moreover, inhibiting SHP-1 with TPI-1 treatment post- Poly (I:C) administration significantly exacerbated testicular inflammation and apoptosis, underscoring SHP-1’s critical protective role. These findings highlight the therapeutic potential of targeting SHP-1 and STAT3 pathways in treating orchitis, advancing our understanding of the pathophysiology of testicular inflammation and suggesting new strategies for managing this condition.Author details: Please check if the designated corresponding authors affiliation is correctly identify and amend if necessary. Please see the attached file containing the updated author information for our manuscript. Author names: Please confirm if all the authors names are presented accurately and in the correct sequence. Kindly check and confirm whether the names of all authors has been processed correctly and amend if necessary. Please see the attached file containing the updated author information for our manuscript.

Male meiotic germ cell including the spermatozoa represent a great challenge to the immune system, as they appear long after the establishment of normal immune tolerance mechanisms. The capacity of the testes to tolerate autoantigenic germ cells as well as survival of allogeneic organ engrafted in the testicular interstitium have led to consider the testis an immunologically privileged site. Disruption of this immune privilege following trauma, tumor, or autoimmune orchitis often results in male infertility. Strong evidence indicates that indoleamine 2,3-dioxygenase (IDO) has been implicated in fetal and allograft tolerance, tumor immune resistance, and regulation of autoimmune diseases. IDO and tryptophan 2,3-dioxygenase (TDO) catalyze the same rate-limiting step of tryptophan metabolism along a common pathway, which leads to tryptophan starvation and generation of catabolites collectively known as kynurenines. However, the relevance of tryptophan metabolism in testis pathophysiology has not yet been explored. Here we assessed the in vivo role of IDO/TDO in experimental autoimmune orchitis (EAO), a model of autoimmune testicular inflammation and immunologically impaired spermatogenesis. EAO was induced in adult Wistar rats with testicular homogenate and adjuvants. Control (C) rats injected with saline and adjuvants and normal untreated rats (N) were also studied. mRNA expression of IDO decreased in whole testes and in isolated Sertoli cells during EAO. TDO and IDO localization and level of expression in the testis were analyzed by immunostaining and Western blot. TDO is expressed in granulomas from EAO rats, and similar protein levels were observed in N, C, and EAO groups. IDO was detected in mononuclear and endothelial cells and reduced IDO expression was detected in EAO group compared to N and C rats. This phenomenon was concomitant with a significant reduction of IDO activity in EAO testis measured by tryptophan and kynurenine concentrations (HPLC). Finally, in vivo inhibition of IDO with 1-methyl-tryptophan increased severity of the disease, demonstrating down regulation of IDO-based tolerance when testicular immune regulation was disrupted. We present evidence that an IDO-based mechanism is involved in testicular immune privilege.

Genital tract infections are common causes of male infertility, and most of diagnosed men are asymptomatic. This study examined the effect of gallic acid (GA) against lipopolysaccharide (LPS)-induced testicular inflammation. Thirty-two Spraque Dawley , 2.5-3 month-old male rats were separated into four groups ( n  = 8). Control group; saline at 3 ml/kg, and in the GA group; GA was dissolved in saline, by gavage at 100 mg/kg for 14 days. LPS group; LPS 5 mg/kg as a single dose was given intraperitoneal on the 11th day. LPS + GA group; GA was given for 14 days and LPS 5 mg/kg on the 11th day. After 72 h of LPS injection, all samples were collected. Semen analysis, biochemical assays, histological evaluations, and immunohistochemical or Western blot analyses for nuclear factor-kappa B (NF-κB) and Prokineticin 2/prokineticin receptor 1(PK2/PKR1) pathways were performed. There was a significant decrease in body and testicular weight, sperm parameters, serum testosterone level, mean seminiferous tubule diameter, germinal epithelial thickness, and Johnsen score in the LPS group compared to control and GA groups. However, a significant increase was found in interstitial space width, percentage of abnormal sperm, NF-κB and PK2 immunoreactivities, and expression of PK2 and PKR1 proteins. In the LPS + GA group, GA administration was observed to significantly prevent these adverse effects. In conclusion, the inhibitory effects of GA on the NF-κB and PK2/PKR1 pathways not only suppressed the inflammatory response but also restored impaired sperm parameters and testicular structure. These findings indicate GA’s potential for treating testicular inflammation and protecting male reproductive health.

Experimental autoimmune epididymo-orchitis (EAEO) is a model of chronic inflammation, induced by immunisation with testicular antigens, which reproduces the pathology of some types of human infertility. Activins A and B regulate spermatogenesis and steroidogenesis, but are also pro-inflammatory, pro-fibrotic cytokines. Expression of the activins and their endogenous antagonists, inhibin and follistatin, was examined in murine EAEO. Adult untreated and adjuvant-treated control mice showed no pathology. All mice immunised with testis antigens developed EAEO by 50 days, characterised by loss of germ cells, immune cell infiltration and fibrosis in the testis, similar to biopsies from human inflamed testis. An increase of total CD45+ leukocytes, comprising CD3+ T cells, CD4 + CD8− and CD4 + CD25+ T cells, and a novel population of CD4 + CD8+ double positive T cells was also detected in EAEO testes. This was accompanied by increased expression of TNF, MCP-1 and IL-10. Activin A and B and follistatin protein levels were elevated in EAEO testes, with peak activin expression during the active phase of the disease, whereas mRNA expression of the inhibin B subunits ( Inha and Inhbb ) and activin receptor subunits ( Acvr1b and Acvr2b ) were downregulated. These data suggest that activin–follistatin regulation may play a role during the development of EAEO.