MEHP-induced rat testicular inflammation does not exacerbate germ cell apoptosis

The blood-testis barrier disruption is a prerequisite for toxicant-induced peritubular macrophage increases in the testis of peripubertal rats

Peritubular macrophages (PTMφ) are predominantly localized near spermatogonial stem cells in the testis. We previously revealed that exposure of peripubertal male Fischer rats to mono-(2-ethylhexyl) phthalate (MEHP) leads to increased PTMφs in the testis. The mechanisms that trigger increases in PTMφs in the testis are poorly understood. However, MEHP exposure is known to both induce spermatocyte apoptosis and to perturb the blood-testis barrier (BTB). This study aims to elucidate the association between the disruption of BTB and the increases of PTMφs in the testis by comparing the effects observed with MEHP to 2 other testicular toxicants with variable effects on the BTB and subtype of germ cell undergoing apoptosis. Methoxyacetic acid (MAA) acts directly on spermatocytes and does not affect BTB function, whereas cadmium chloride (CdCl2) induces profound injury to BTB. The results indicated that MAA exposure significantly increased spermatocyte apoptosis, whereas no significant changes in the numbers of PTMφs in the testis occurred. In contrast, CdCl2 exposure disrupted BTB function and increased the abundance of PTMφs in the testis. To further investigate whether MEHP-induced changes in BTB integrity accounted for the increase in PTMφs, a plasmid for LG3/4/5, the functional component of laminin-alpha 2, was overexpressed in the testis to stabilize BTB integrity before MEHP exposure. The results showed that LG3/4/5 overexpression substantially reduced the ability of MEHP to compromise BTB integrity and prevented the increase in PTMφ numbers after MEHP exposure. These results indicate that BTB disruption is necessary to increase PTMφs in the testis induced by toxicants.

Responses of peritubular macrophages and the testis transcriptome profiles of peripubertal and adult rodents exposed to an acute dose of MEHP

Exposure of rodents to mono-(2-ethylhexyl) phthalate (MEHP) is known to disrupt the blood-testis barrier and cause testicular germ cell apoptosis. Peritubular macrophages (PTMφ) are a newly identified type of testicular macrophage that aggregates near the spermatogonial stem cell niche. We have previously reported that MEHP exposure increased the numbers of PTMφs by 6-fold within the testis of peripubertal rats. The underlying mechanism(s) accounting for this change in PTMφs and its biological significance is unknown. This study investigates if MEHP-induced alterations in PTMφs occur in rodents (PND 75 adult rats and PND 26 peripubertal mice) that are known to be less sensitive to MEHP-induced testicular toxicity. Results show that adult rats have a 2-fold higher basal level of PTMφ numbers than species-matched peripubertal animals, but there was no significant increase in PTMφ numbers after MEHP exposure. Peripubertal mice have a 5-fold higher basal level of PTMφ compared with peripubertal rats but did not exhibit increases in number after MEHP exposure. Further, the interrogation of the testis transcriptome was profiled from both the MEHP-responsive peripubertal rats and the less sensitive rodents via 3' Tag sequencing. Significant changes in gene expression were observed in peripubertal rats after MEHP exposure. However, adult rats showed lesser changes in gene expression, and peripubertal mice showed only minor changes. Collectively, the data show that PTMφ numbers are associated with the sensitivity of rodents to MEHP in an age- and species-dependent manner.

The Impact of Chronic Phthalate Exposure on Rodent Anxiety and Cognition

Background

There is a growing importance for environmental contributions to psychiatric disorders and understanding the impact of the exposome (i.e., pollutants and toxins). For example, increased biomonitoring and epidemiological studies suggest that daily phthalate chemical exposure contributes to neurological and behavioral abnormalities; however, these mechanisms remain poorly understood. Therefore, the current study was aimed at examining the effects of chronic phthalate exposure on rodent anxiety behaviors and cognition and the impact on hypothalamic-pituitary-adrenal axis function.

Methods

Adult male mice (C57BL6/J) were administered MEHP via drinking water (1 mg/mL), and anxiety-like behavior and cognition combined with hypothalamic-pituitary-adrenal axis and inflammatory assays were assessed after 3 weeks of MEHP exposure.

Results

MEHP-treated mice exhibited enhanced generalized anxiety-like behaviors, as demonstrated by reduced time spent in the open-arm of the elevated plus maze and center exploration in the open field. Tests of spatial memory and cognition were unchanged. Following MEHP administration, circulating levels of corticosterone and proinflammatory cytokines were significantly increased, while at the tissue level, there were MEHP-dependent reductions in glucocorticoid metabolism genes Hsd11b1 and Hsd11b2.

Conclusions

These data suggest that chronic MEHP exposure leads to enhanced generalized anxiety behaviors independent of rodent measures of cognition and memory, which may be driven by MEHP-dependent effects on hypothalamic-pituitary-adrenal axis and peripheral glucocorticoid metabolism function.

Mono-(2-ethylhexyl) phthalate (MEHP) reversibly disrupts the blood-testis barrier (BTB) in pubertal rats

The blood-testis barrier (BTB) is constituted by tight junctions between adjacent Sertoli cells (SC) that create a specialized adluminal microenvironment to foster the development of spermatocytes and spermatids. The BTB is a well-studied target of numerous environmental toxicants, including di-(2-ethylhexyl) phthalate (DEHP), a compound widely used in various consumer products. MEHP is the active toxic metabolite of DEHP that has long been recognized in postnatal rodents to disrupt SC function. This study evaluates the impact of MEHP on the integrity of the BTB in both pubertal and adult rats and the signal transduction pathways known to be involved in the disruption of the BTB. Treatment of prepubertal rats with 700 mg/kg MEHP for 24 hours functionally disrupted the BTB integrity. A similar treatment of adult rats with MEHP did not disrupt the integrity of the BTB. The observed disruption of the BTB integrity in the MEHP-treated prepubertal rats occurred concomitantly with a decreased expression and mislocalization of both the ZO1 and occludin tight junction-associated proteins, as well as sloughing of spermatocytes and spermatids. At this same time, MEHP treatment induced a transient surge of p44/42 mitogen-activated protein kinase (MAPK) pathway. Interestingly, after a recovery period of 5 weeks, the BTB recovered and was functionally intact. This is the first report to indicate that acute MEHP exposure of prepubertal rats, but not adult rats, disrupts the functional integrity of the BTB and that this effect on the BTB is reversible.

Exposure to the non-phthalate plasticizer di-heptyl succinate is less disruptive to C57bl/6N mouse recovery from a myocardial infarction than DEHP, TOTM or related di-octyl succinate

Phthalate plasticizers are incorporated into plastics to make them soft and malleable, but are known to leach out of the final product into their surroundings with potential detrimental effects to human and ecological health. The replacement of widely-used phthalate plasticizers, such as di-ethylhexyl phthalate (DEHP), that are of known toxicity, by the commercially-available alternative Tris(2-ethylhexyl) tri-mellitate (TOTM) is increasing. Additionally, several newly designed "green" plasticizers, including di-heptyl succinate (DHPS) and di-octyl succinate (DOS) have been identified as potential replacements. However, the impact of plasticizer exposure from medical devices on patient recovery is unknown and, moreover, the safety of TOTM, DHPS, and DOS is not well established in the context of patient recovery. To study the direct effect of clinically based chemical exposures, we exposed C57bl/6 N male and female mice to DEHP, TOTM, DOS, and DHPS during recovery from cardiac surgery and assessed survival, cardiac structure and function, immune cell infiltration into the cardiac wound and activation of the NLRP3 inflammasome. Male, but not female, mice treated in vivo with DEHP and TOTM had greater cardiac dilation, reduced cardiac function, increased infiltration of neutrophils, monocytes, and macrophages and increased expression of inflammasome receptors and effectors, thereby suggesting impaired recovery in exposed mice. In contrast, no impact was detected in female mice and male mice exposed to DOS and DHPS. To examine the direct effects in cells involved in wound healing, we treated human THP-1 macrophages with the plasticizers in vitro and found DEHP induced greater NLRP3 expression and activation. These results suggest that replacing current plasticizers with non-phthalate-based plasticizers may improve patient recovery, especially in the male population. In our assessment, DHPS is a promising possibility for a non-toxic biocompatible plasticizer.

Macrophage-Related Testicular Inflammation in Individuals with Idiopathic Non-Obstructive Azoospermia: A Single-Cell Analysis

Male infertility is a global issue that seriously affects reproductive health. This study aimed to understand the underlying causes of idiopathic non-obstructive azoospermia (iNOA), which is a type of male infertility with unknown origins that accounts for 10-15% of cases. By using single-cell analysis techniques, we aimed to uncover the mechanisms of iNOA and gain insight into the cellular and molecular changes in the testicular environment. In this study, we performed bioinformatics analysis using scRNA-seq and microarray data obtained from the GEO database. The analysis included techniques such as pseudotime analysis, cell-cell communication, and hdWGCNA. Our study showed a significant difference between the iNOA and the normal groups, indicating a disorder in the spermatogenic microenvironment in iNOA. We observed a reduction in the proportion of Sertoli cells and blocked germ cell differentiation. Additionally, we found evidence of testicular inflammation related to macrophages and identified ODF2 and CABYR as potential biomarkers for iNOA.

The Impact of Chronic Phthalate Exposure on Rodent Anxiety and Cognition

There is a growing importance for environmental contributions to psychiatric disorders and understanding the impact of the exposome (i.e., pollutants and toxins). Increased biomonitoring and epidemiological studies, for example, suggest that daily phthalate chemical exposure contribute to neurological and behavioral abnormalities, however these mechanisms remain poorly understood. The current study therefore aimed to examine the effects of chronic phthalate exposure on rodent anxiety behaviors, cognition, and the impact on hypothalamic-pituitary- adrenal (HPA)-axis function. Adult male mice (C57BL6/J) were administered mono-2-ethylhexyl phthalate (MEHP) via drinking water (1 mg/ml), and anxiety-like behavior, cognition combined with HPA- axis and inflammatory assays were assessed after 3 weeks of MEHP exposure. MEHP-treated mice exhibited enhanced generalized anxiety-like behaviors, as demonstrated by reduced time spent in the open-arm of the elevated plus maze (EPM) and center exploration in the open field (OF). Tests of spatial, cognition and memory function were unchanged. Following MEHP administration, circulating levels of corticosterone and pro- inflammatory cytokines were significantly increased, while at the tissue level, MEHP-dependent reductions in glucocorticoid metabolism genes 11β-hydroxysteroid dehydrogenase (11β-HSD) 1 and 2. These data suggest that chronic MEHP exposure leads to enhanced generalized-anxiety behaviors independent of rodent measures of cognition and memory, which maybe driven by MEHP-dependent effects on HPA-axis and peripheral glucocorticoid metabolism function.

Predictive value of hematological parameters in testicular salvage: A 12-year retrospective review

PURPOSE

This study aimed to evaluate the predictive value of preoperative hematological parameters for testicular salvage in patients with testicular torsion.

METHODS

Clinical data of patients with testicular torsion treated at Shenzhen Children's Hospital from January 2010 to December 2021 were analyzed retrospectively. The data collected included age, symptom duration, degree of spermatic cord torsion, the surgical approach adopted, hematological parameters, and ultrasound results during postoperative follow-up.

RESULTS

The study participants were classified into three groups as follows: the successful testicular salvage group (n = 43), failed testicular salvage group (n = 124), and control group (n = 100). Univariate analysis showed that testicular salvage was related to patient age, duration of symptoms, spermatic cord torsion degree, white blood cell count, lymphocyte count, monocyte count, platelet-lymphocyte ratio, and neutrophil-lymphocyte ratio. However, multivariate analysis revealed that symptom duration (OR = 0.948, P < 0.001), degree of spermatic cord torsion (OR = 0.994, P < 0.001), and monocyte count (OR = 0.020, P = 0.011) were independent risk factors for testicular torsion salvage. The monocyte count in the failed salvage group was significantly higher than in the successful salvage and control groups (P < 0.01).

CONCLUSION

Monocyte count is an independent predictor of testicular salvage. Therefore, clinicians can predict the success rate of testicular salvage in patients with testicular torsion based on the monocyte count.

Peritubular Macrophages Are Recruited to the Testis of Peripubertal Rats After Mono-(2-Ethylhexyl) Phthalate Exposure and Is Associated With Increases in the Numbers of Spermatogonia

Peripubertal exposure of male rodents to the phthalate metabolite mono-(2-ethylhexyl) phthalate (MEHP) causes testicular inflammation, spermatocyte apoptosis, and disruption of the blood-testis barrier. The MEHP-induced inflammatory response in the testis includes an infiltration of macrophages and neutrophils, although the cause and purpose of this response is unknown. Recently, a population of testicular macrophages known as peritubular macrophages that are phenotypically distinct from those resident in interstitium was described in mice. Peritubular macrophages aggregate near the spermatogonial stem cell niche and are believed to stimulate their differentiation. We hypothesized that if testicular peritubular macrophages do indeed stimulate spermatogonial differentiation, MEHP exposure would result in an increase of peritubular macrophages to stimulate the replacement of lost spermatocytes. Male rats were exposed to 700 mg/kg MEHP or corn oil (vehicle control) via oral gavage at postnatal day 28 and euthanized at 48 h, 1 or 2 weeks later. Seminiferous tubules were stained with immunofluorescent markers for macrophages (major histocompatibility complex class II [MHC-II+]) and undifferentiated spermatogonia (PLZF). Peritubular macrophages were observed in rat testis: MHC-II+ cells on the surface of seminiferous tubules with heterogeneous morphology. Quantification of MHC-II+ cells revealed that, unlike in the mouse, their numbers did not increase through puberty (2-week period). MEHP increased macrophage presence by 6-fold 48 h after exposure and remained elevated by 2-fold 2 weeks after exposure. An increase of differentiating spermatogonia occurred 2 weeks after MEHP exposure. Taken together, our results suggest that peritubular macrophages play a crucial role in the testis response to acute injury and the subsequent recovery of spermatogenesis.

Interleukin 17A deficiency alleviates fluoride-induced testicular injury by inhibiting the immune response and apoptosis

The reproductive toxicity of fluoride (F) has been verified by various epidemiological and experimental studies. Our previous work suggested that the interleukin 17A (IL-17A) is involved in the testicular damage induced by excessive F exposure. In this study, we further investigated the role of IL-17A in F-induced testicular injury. Wild type (WT) and IL-17A knockout (IL-17A^-/-) mice were exposed to 0, 25, 50, or 100 mg/L sodium fluoride (NaF) for 90 days. We found that exposure to excessive F levels caused testicular damage, decreased semen quality, negatively affected testicular morphology, and increased the inflammatory response. Specifically, excessive F intake increased the expression levels of IL-17A in the testis and increased the protein levels of Act1, NF-κB, IL-17R, C/EBP-α, and TRAF6 in the IL-17A signaling pathway. The increase in IL-17A expression corresponded to increases expression of IL-17R, IL-6, IL-23, IL-1β, TGF-β and TNF-α as assessed by RT-PCR and ELISA assays. Remarkably, IL-17A knockout in mice ameliorated the effects of F on testicular damage, semen quality, testicular morphology, and the immune response. Additionally, we found the in vitro exposure of Leydig cells to NaF and recombinant IL-17A led to abnormal apoptosis and a decrease in testosterone secretion. Our findings prove that IL-17A plays a key role in the exacerbation of testicular injuries in F-exposed mice, and that IL-17A deficiency can alleviate F-induced injury by inhibiting the immune response and apoptosis in the testis. These data suggest that targeting IL-17A may be a useful therapeutic strategy for treating F-mediated toxicity in the testis.

Recovery From a Myocardial Infarction Is Impaired in Male C57bl/6 N Mice Acutely Exposed to the Bisphenols and Phthalates That Escape From Medical Devices Used in Cardiac Surgery

Bisphenols and phthalates leach from medical devices, and this exposure is likely to increase in postcardiac surgery patients. Previous studies suggest that such chemical exposure may impact recovery and wound healing, yet the direct effects of bisphenols and phthalates are unknown in this context. To study the direct effect of clinically based chemical exposures, we measured the metabolites representative of 6 bisphenols and 10 phthalates in men before and after cardiac surgery and then replicated this exposure in a mouse model of cardiac surgery and assessed survival, cardiac function and inflammation. Bisphenol A (BPA), di-ethyl hexyl phthalate (DEHP), butylbenzyl phthalate, di-isodecyl phthalate, and di-n-butyl phthalate metabolites were increased after surgery. DEHP exposure predominated, was positively correlated with duration on the cardiopulmonary bypass machine and exceeded its tolerable daily intake limit by 37-fold. In vivo, C57bl/6 N male mice treated with BPA+phthalates during recovery from surgery-induced myocardial infarction had reduced survival, greater cardiac dilation, reduced cardiac function and increased infiltration of neutrophils, monocytes and macrophages suggesting impaired recovery. Of interest, genetic ablation or estrogen receptor beta (ERβ) antagonism did not improve recovery and replacement of DEHP with tri-octyl trimellitate or removal of BPA from the mixture did not ameliorate these effects. To examine the direct effects on inflammation, treatment of human THP-1 macrophages with BPA and phthalates induced a dysfunctional proinflammatory macrophage phenotype with increased expression of M1-type macrophage polarization markers and MMP9 secretion, yet reduced phagocytic activity. These results suggest that chemicals escape from medical devices and may impair patient recovery.

Mono (2-ethylhexyl) phthalate (MEHP) triggers the proliferation of hemangioma-derived endothelial cells via YAP signals

Hemangioma (HA) is tumor formed by hyper-proliferation of vascular endothelial cells. However, the potential effects of mono-(2-ethylhexyl) phthalate (MEHP) on the progression of HA are not well illustrated. Our present study revealed that MEHP exposure can significantly increase the in vitro proliferation of hemangioma-derived endothelial cells (HemECs). MEHP treatment can activate yes-associated protein (YAP), a key effector of Hippo pathway, by inhibiting its phosphorylation. The dephosphorylation of YAP induced by MEHP can promote the nuclear accumulation of YAP. Knockdown of YAP or its inhibitor can block MEHP triggered cell proliferation. MEHP can increase the levels of precursor and mature mRNA of YAP in HemECs. As well, MEHP extended the half-life of YAP protein. Mechanistically, MEHP can decrease the phosphorylation of YAP via suppressing the activity of large tumor suppressor kinase 1/2 (LATS1/2) to inhibit it induced degradation of YAP. Further, MEHP increased the expression of interferon regulatory factor 1 (IRF1), which can bind to the promoter of YAP to initiate its transcription. Collectively, we revealed that Hippo-YAP signal is involved in MEHP-induced proliferation of HA cells.