Deoxynivalenol Induces Blood-Testis Barrier Dysfunction through Disrupting p38 Signaling Pathway-Mediated Tight Junction Protein Expression and Distribution in Mice

Millettia speciosa Champ. Leguminosae ameliorates testicular damage in mice by repairing of blood-testis barrier dysfunction and testosterone synthesis

ETHNOPHARMACOLOGICAL RELEVANCE

Millettia speciosa Champ. Leguminosae (MSC), a medicinal-edible plant in southern China, according to the records in Lingnan caiyaolu, MSC is known for its functions of "tonifying deficiency and consolidating essence." It is also empirically used to enhance male reproductive health. However, the protective mechanisms of MSC on the testes require further investigation.

AIM OF THE STUDY

This study aims to investigate the protective effect of MSC extract against cyclophosphamide (CP)-induced testicular damage.

METHODS

The components of MSC were conducted using ultra-performance liquid chromatography combined with UPLC-ESI-MS/MS. Testicular dysfunction was induced in ICR mice by intraperitoneal injection of CP (50 mg/kg, once a day for one week), and MSC (400 or 800 mg/kg) was administered orally daily for four weeks to evaluate its effectiveness in alleviating CP-induced testicular dysfunction. Sperm quality was assessed by computer-assisted semen analysis (CASA), hematoxylin-eosin (H&E) staining, immunohistochemistry (IHC) immunofluorescence (IF) and in situ hybridization (ISH) were conducted to analyze the recovery to testicular function. Quantitative analysis of ROS indicators and hormones was performed using enzyme-linked immunosorbent assay (ELISA). The expressions of related genes were evaluated by Quantitative real-time PCR (RT-qPCR).

RESULTS

MSC alleviated CP-induced reductions in body weight, testicular index, and epididymal index. It enhanced antioxidant enzyme activity such as superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and upregulated related genes (Sod1, Sod2, Sod3, and Cat). MSC also improved sperm quality, restored testosterone (T) levels by upregulating genes involved in T synthesis (Cyp17a1, Cyp11a1, and Star), and reinforced the blood-testis barrier (BTB) through increased expression of Zonula occludens-1, Connexin43, and N-Cadherin. Notably, MSC reinitiated the stalled meiotic process, as evidenced by restored expression of Stra8, and the reappearance of spermatogenic cells in the seminiferous tubules and their correct localization.

CONCLUSION

This study demonstrates the anti-oxidative stress capability of MSC and highlights its multifaceted protective mechanisms against CP-induced testicular damage, suggesting its potential as a phytotherapeutic treatment for testicular damage.

Deoxynivalenol and male reproductive toxicity: Unraveling the hidden risks

Deoxynivalenol (DON) is a highly prevalent mycotoxin known for its deleterious effects on the gastrointestinal and immune systems. Recent studies have also demonstrated its potential to impair reproductive function. This review compiles current evidence on the impact of DON on male reproductive organs, with particular emphasis on its hormonal suppressive effects, disruption of the germinal epithelium, and compromise of the blood-testis barrier. This review also highlights the impact of DON on less-explored reproductive organs, such as the epididymis, prostate, and seminal vesicles. These effects are primarily mediated by increased oxidative stress, inflammation, and apoptosis. Collectively, these alterations result in reduced sperm quality and quantity, thereby impairing male fertility. In addition, we examine studies evaluating the consequences of parental DON exposure on offspring development, which reveal adverse effects across multiple developmental stages. The findings presented consolidate the classification of DON as a relevant toxicant to male reproductive health.

Trichothecenes toxicity in humans and animals: Unraveling the mechanisms and harnessing phytochemicals for prevention

Mycotoxins are the major widespread hazardous substances in feed and food and are widely distributed throughout the world. Mycotoxins are a major food safety concern since they can produce substantial toxic and carcinogenic consequences in human and animals when consumed. Trichothecenes (TCTs), a class of highly toxic mycotoxins mainly generated by Fusarium species, are among the most prevalent food pollutants. Deoxynivalenol (DON), largely biosynthesized by Fusarium graminearum and Fusarium culmorum, along with T-2 toxin generated chiefly by Fusarium langsethiae and Fusarium sporotrichioides, represent the most agriculturally significant TCT subtypes. There are still no effective control strategies. Furthermore, phytochemicals have received widespread attention as natural compounds with strong antioxidant, anti-inflammatory and detoxifying effects. Because of the powerful antioxidant effects of phytochemicals, researchers have begun to look at ways to counteract the intense toxicity of TCT. Focusing on the global challenge of TCTs, this comprehensive review systematically examines contamination patterns of DON and T-2 toxin, elucidates their multi-organ toxicity pathways, and critically evaluates emerging evidence on phytochemical-based interventions targeting DON and T-2 toxin-induced health impairments. It concludes that These findings demonstrate that phytochemicals counteract DON and T-2 toxin toxicity by suppressing oxidative stress-mediated pathways, including pyroptosis, ferroptosis, apoptosis, and inflammatory responses. Accordingly, the direct addition of phytochemicals to food and feed is expected to be a promising prospect for the detoxification of DON and T-2 toxin, considering their safety, efficiency, and accessibility.

Deoxynivalenol exposure-related male reproductive toxicity in mammals: Molecular mechanisms, detoxification and future directions

An increasing body of evidence indicates that exposure to widespread, environmental and food contaminants such as mycotoxins may cause endocrine disorders and infertility. Deoxynivalenol (DON), which is a toxic secondary metabolite produced by Fusarium fungi, can lead to multiple harmful effects in humans and animals, such as hepatotoxicity, nephrotoxicity, immunotoxicity, gastrointestinal toxicity, neurotoxicity, genetic toxicity and carcinogenicity. Recently, there has been growing concern about DON-induced male infertility. Exposure to DON and its metabolites can damage the structure and function of male reproductive organs, resulting in impairment of gametogenesis and thus impaired fertility. Potential molecular mechanisms involve oxidative stress, inflammatory response, mitochondrial dysfunction, apoptosis, cell cycle arrest, pyroptosis, and ferroptosis. Moreover, several signaling pathways, including nuclear factor-kappa B, mitogen-activated protein kinase, NLR family pyrin domain containing 3, nuclear factor erythroid 2-related factor 2, AMP-activated protein kinase, mitochondrial apoptotic pathways, and microRNAs are involved in these detrimental biological processes. Research has shown that several antioxidants, small-molecule inhibitors, or proteins (such as lactoferrin) supplementation can potentially offer protective effects by targeting these signaling pathways. This review comprehensively summarizes the harmful effects of DON exposure on male reproductive function in mammals, the underlying molecular mechanisms and emphasizes the potential of several small molecules as protective therapeutics. In the further, the systematic risk assessment when DON at environmental exposure doses to human reproductive health, the in-depth and precise molecular mechanism investigation using emerging technologies, and the development of more effective intervention strategies warrant urgent investigation.

Curcumin Alleviates DON-Induced Intestinal Epithelial Barrier Disruption by Improving Ribotoxic Stress-Associated p38 Pathway-Mediated TJ Injury, Apoptosis, and Cell Cycle Arrest

Deoxynivalenol (DON) is a pervasive ribotoxic stressor that induces intestinal epithelial barrier disruption by impairing tight junctions (TJs) and causing cellular damage. Curcumin (CUR), known for its enteroprotective properties and low toxicity, has been shown to attenuate DON-induced intestinal epithelial barrier injury. However, the underlying mechanisms are still unclear. In this study, we established in vivo and in vitro models using 30 male Kunming mice and IPEC-J2 cells to investigate the mechanisms by which CUR alleviates DON-induced intestinal epithelial barrier injury. The results showed that CUR markedly reduced DON-induced increases in intestinal permeability by restoring TJ protein expression (Claudin-4 and occludin) and preventing fiber-shaped actin (F-actin) contraction. CUR also attenuated DON-induced apoptosis by downregulating p53 and caspase activation and alleviated the G1 cell cycle arrest by reducing p21 expression. Mechanistically, CUR inhibited the activation of the ribosomal stress response (RSR)-associated p38 pathway, evidenced by decreased phosphorylation of p38, GSK3β, and ATF-2. The p38 activator dehydrocorydaline reversed CUR's protective effects. In conclusion, CUR alleviates DON-induced intestinal epithelial barrier disruption by improving RSR-associated p38 pathway-mediated TJ injury, apoptosis, and cell cycle arrest. These findings highlight the potential of CUR as a therapeutic agent for mitigating mycotoxin-induced intestinal dysfunction and suggest new avenues for drug target discovery.

Deoxynivalenol induces spleen damage, apoptosis, and inflammation in mice by increasing mitochondrial reactive oxygen species: Protective effects of curcumin

Deoxynivalenol (DON), a Fusarium mycotoxin, causes spleen apoptosis and inflammation, which damage the organ. Curcumin (Cur) is a member of the ginger family. It has anti-apoptotic and anti-inflammatory effects that maintain the health of the organism's immune system. Here, the protective effects of Cur against DON-induced spleen damage were explored. First, we found DON (2.4 mg/kg body weight) decreased the expression of manganese superoxide dismutase, mitochondrial membrane potential, adenosine triphosphate, and disturbed hematoxylin and eosin staining in mice spleen. The results confirmed that DON causes mitochondrial reactive oxygen species (mtROS) overproduction leading to spleen damage. Second, we found DON decreased the expression of mitochondrial apoptosis-inducing factor (AIF) and B-cell lymphoma-2 (Bcl-2), and increased the expression of nuclear AIF, Bcl2-associated X (Bax), cysteine-aspartate protease-3 (caspase-3), caspase-9. Mitoquinone is a mitochondria-targeted antioxidant that can prevent of mitochondrial oxidative damage. These expression increases were not observed in the mitoquinone-treated group, confirming that mtROS was an upstream regulatory target of apoptosis and inflammation in DON-exposed mice spleens. Finally, we confirmed that Cur (50 or 100 mg/kg body weight) attenuated DON-induced apoptosis and inflammation by inactivating mtROS. Collectively, these results confirm that DON causes spleen damage by increasing mtROS, and the protective effects of curcumin.

Thermosensitive Injectable Dual Drug-Loaded Chitosan-Based Hydrogels for Treating Bacterial Endometritis

Endometritis, a prevalent obstetric condition primarily caused by Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), significantly threatens the reproductive performance of female animals. In this study, thermosensitive injectable chitosan (CS)/β-glycerophosphate (β-GP) hydrogels loaded with berberine (BBR) and carvacrol (CAR) were prepared for endometritis treatment. In vitro, BBR/CAR-CS/β-GP hydrogels exhibited rapid gelation within 5 min at 37 °C, excellent injectability, and more than 90% degradation within 30 days under enzymatic action. The dual drug-loaded system also exhibited controlled release of BBR and CAR and demonstrated the antimicrobial activity against E. coli and S. aureus. In vivo, uterine injection of BBR/CAR-CS/β-GP hydrogels alleviated infection-induced injuries and reduced the bacterial load in infected uterine tissues. In summary, these findings highlight the potential of BBR/CAR-CS/β-GP hydrogels as innovative carriers for drug delivery targeting endometritis.

Testicular immunity

The testis is a unique environment where immune responses are suppressed to allow the development of sperm that possess autoimmunogenic antigens. There are several contributors responsible for testicular immune privilege, including the blood-testis barrier, testicular immune cells, immunomodulation by Sertoli cells, and high levels of steroid hormones. Despite multiple mechanisms in place to regulate the testicular immune environment, pathogens that disrupt testicular immunity can lead to long-term effects such as infertility. If testicular immunity is disturbed, autoimmune reactions can also occur, leading to aberrant immune cell infiltration and subsequent attack of autoimmunogenic germ cells. Here we discuss cellular and molecular factors underlying testicular immunity and how testicular infection or autoimmunity compromise immune privilege. We also describe infections and autoimmune diseases that impact the testis. Further research into testicular immunity will reveal how male fertility is maintained and will help update therapeutic strategies for infertility and other testicular disorders.

The potential of orally exposed risk factors and constituents aggravating food allergy: Possible mechanism and target cells

Food allergy is a significant concern for the health of humans worldwide. In addition to dietary exposure of food allergens, genetic and environmental factors also play an important role in the development of food allergy. However, only the tip of the iceberg of risk factors in food allergy has been identified. The importance of food allergy caused by orally exposed risk factors and constituents, including veterinary drugs, pesticides, processed foods/derivatives, nanoparticles, microplastics, pathogens, toxins, food additives, dietary intake of salt/sugar/total fat, vitamin D, and therapeutic drugs, are highlighted and discussed in this review. Moreover, the epithelial barrier hypothesis, which is closely associated with the occurrence of food allergy, is also introduced. Additionally, several orally exposed risk factors and constituents that have been reported to disrupt the epithelial barrier are elucidated. Finally, the possible mechanisms and key immune cells of orally exposed risk factors and constituents in aggravating food allergy are overviewed. Further work should be conducted to define the specific mechanism by which these risk factors and constituents are driving food allergy, which will be of central importance to the targeted therapy of food allergy.

Chlorogenic acid can improve spermatogenic dysfunction in rats with varicocele by regulating mitochondrial homeostasis and inhibiting the activation of NLRP3 inflammasomes by oxidative mitochondrial DNA and cGAS/STING pathway

In recent years, Varicocele (VC) has been recognized as a common cause of male infertility that can be treated by surgery or drugs. How to reduce the damage of VC to testicular spermatogenic function has attracted extensive attention in recent years. Among them, overexpressed ROS and high levels of inflammation may play a key role in VC-induced testicular damage. As the key mediated innate immune pathways, cGAS-STING shaft under pathological conditions, such as in cell and tissue damage stress can be cytoplasmic DNA activation, induce the activation of NLRP3 inflammatory corpuscle, triggering downstream of the inflammatory cascade reaction. Chlorogenic acid (CGA), as a natural compound from a wide range of sources, has strong anti-inflammatory and antioxidant activities, and is a potential effective drug for the treatment of varicocele infertility. The aim of this study is to investigate the role of CGA in the spermatogenic dysfunction of the rat testis induced by VC and the potential mechanisms. The results of this study have shown that CGA gavage treatment ameliorated the pathological damage of seminiferous tubules, increased the number of sperm in the lumen, and increased the expression levels of Occludin and ZO-1, which indicated the therapeutic effect of CGA on spermatogenic dysfunction in the testis of VC rats. Meanwhile, the damage of mitochondrial structure was alleviated and the expression levels of ROS, NLRP3 and pro-inflammatory cytokines (IL-1β, IL-6, IL-18) were significantly reduced in the testicular tissues of model rats after CGA treatment. In addition, we demonstrated for the first time the high expression status of cGAS and STING in testicular tissues of VC model rats, and this was ameliorated to varying degrees after CGA treatment. In conclusion, this study suggests that CGA can improve the spermatogenic function of the testis by reducing mitochondrial damage and inhibiting the activation of the cGAS-STING axis, inhibiting the activation of the NLRP3 inflammasome, and improving the inflammatory damage of the testis, highlighting the potential of CGA as a therapeutic agent for varicocele infertility.

ERK/CREB and p38 MAPK/MMP14 Signaling Pathway Influences Spermatogenesis through Regulating the Expression of Junctional Proteins in Eriocheir sinensis Testis

The hemolymph-testis barrier (HTB) is a reproduction barrier in Crustacea, guaranteeing the safe and smooth process of spermatogenesis, which is similar to the blood-testis barrier (BTB) in mammals. The MAPK signaling pathway plays an essential role in spermatogenesis and maintenance of the BTB. However, only a few studies have focused on the influence of MAPK on crustacean reproduction. In the present study, we knocked down and inhibited MAPK in Eriocheir sinensis. Increased defects in spermatogenesis were observed, concurrently with a damaged HTB. Further research revealed that es-MMP14 functions downstream of ERK and p38 MAPK and degrades junctional proteins (Pinin and ZO-1); es-CREB functions in the ERK cascade as a transcription factor of ZO-1. In addition, when es-MMP14 and es-CREB were deleted, the defects in HTB and spermatogenesis aligned with abnormalities in the MAPK. However, JNK impacts the integrity of the HTB by changing the distribution of intercellular junctions. In summary, the MAPK signaling pathway maintains HTB integrity and spermatogenesis through es-MMP14 and es-CREB, which provides insights into the evolution of gene function during barrier evolution.

Deoxynivalenol Induces Intestinal Epithelial Barrier Damage through RhoA/ROCK Pathway-Mediated Apoptosis and F-Actin-Associated Tight Junction Disruption

Deoxynivalenol (DON) poses a serious global food safety risk due to its high toxicity and contamination rate. It disrupts the intestinal epithelial barrier, allowing exogenous toxins to enter the circulation and resulting in sepsis and systemic toxicity. In this research, 32 male Kunming mice and Porcine Small Intestinal Epithelial (IPEC-J2) cells were treated with DON at 0-4.8 mg/kg (7 d) and 0-12 μM (24 h), respectively. Histopathological results revealed that DON disrupted the intestinal epithelial barrier, causing apoptosis and tight junction (TJ) injury. Immunofluorescence and protein expression results showed that DON-induced p53-dependent mitochondrial pathway apoptosis and fibrillar actin (F-actin)-associated TJ injury and that the RhoA/ROCK pathway were activated in mice jejunal tissue and IPEC-J2 cells. Pretreatment with RhoA or ROCK inhibitors (Rosin or Y-27632) maintained DON-induced apoptosis and F-actin-associated TJ injury in IPEC-J2 cells. Thus, DON induces damage to the intestinal epithelial barrier through the RhoA/ROCK pathway-mediated apoptosis and F-actin-associated TJ disruption.

Ferritinophagy-mediated ferroptosis of spermatogonia is involved in busulfan-induced oligospermia in the mice

Busulfan, a bifunctional alkylated chemotherapeutic agent, has male reproductive toxicity and induce oligospermia, which is associated with ferroptosis. However, the specific target cells of busulfan-induced oligospermia triggered by ferroptosis are largely elusive, and the detailed mechanisms also require further exploration. In the present study, busulfan (0.6, and 1.2 mM, 48 h) causes ferroptosis in GC-1 spg cells through inducing Fe2+, ROS and MDA accumulation and functional inhibition of Xc-GSH-GPX4 antioxidant system. After inhibition of ferroptosis by Fer-1 (1 μM, pretreatment for 2 h) or DFO (10 μM, pretreatment for 2 h) reverses busulfan-induced destructive effects in GC-1 spg cells. Furthermore, using RNA-seq and Western blotting, we found that busulfan promotes autophagy-dependent ferritin degradation, as reflected by enriching in autophagy, increased LC3 II, Beclin1 and NCOA4, as well as decreased P62 and ferritin heavy chain 1 (FTH1). Ultimately, GC-1 spg cells and Balb/c mice were treated with busulfan and/or 3-MA, the inhibitor of autophagy. The results displayed that inhibition of autophagy relieves busulfan-induced FTH1 degradation and then blocks the occurrence of ferroptosis in GC-1 spg cells and testicular spermatogonia, which subsequently alleviates busulfan-caused testicular damage and spermatogenesis disorders. In summary, these data collectively indicated that ferroptosis of spermatogonia is involved in busulfan-induced oligospermia and mediated by autophagy-dependent FTH1 degradation, identifying a new target for the therapy of busulfan-induced male infertility.