Environmental pollutants and dysregulation of male puberty—A comparison among species

AMPK pathway is implicated in low level lead-induced pubertal testicular damage via disordered glycolysis

Lead (Pb) is a common environmental pollutant. It has been demonstrated that long-term exposure to Pb at environmental levels may cause severe and irreversible damage to the male reproductive system. Of note, the impairments may originate from environmental Pb exposure at puberty. However, the underlying mechanisms remain unclear. In this study, we administrated male ICR mice with 200 mg/L Pb through the drinking water for 30-, 60-, 90-day from postnatal day 28. RNA sequencing was performed in the control group and the 90-day Pb exposure group. It was found that Pb exposure induced testicular damage, increased oxidative stress levels and poor sperm quality. Bioinformatic analysis displayed 199 genes up-regulated (such as GLUT1 and MCT4 genes) and 156 genes down-regulated (such as GLUT3, PFK1, LDH, CD147 and AMPK genes) in the Pb exposure group compared to the control group. Gene ontology (GO) terms enrichment analysis showed differentially expressed genes (DEGs) are involved in the protein catabolic, cellular catabolic and triglyceride catabolic processes. KEGG pathways enrichment analysis indicated glycerolipid metabolism and AMPK signaling were significantly enriched. Furthermore, experimental verification showed that Pb exposure induces energy dysmetabolism and decreases glycolysis products in mice testicular tissue. The AMPK signaling pathway was found to be deactivated after Pb exposure. The GLUT1, GLUT3, PFK1 and LDH proteins, which play a critical role in the cell glycolysis process, also were decreased. Besides, the expression of CD147 was decreased and the location of CD147 was altered upon Pb exposure. Together, these findings indicated the implication of the AMPK signaling pathway in Pb exposure induced pubertal testicular damage and poor sperm quality by inhibiting cell glycolysis and disordering lactate transportation in testicular cells.

Effect of Nigella sativa and Foeniculum vulgare seeds extracts on male mice exposed to carbendazim

The increasing prevalence of environmental pollutants such as pesticides is a major global problem that affects living organisms. Exposure to environmental pollutants remains a major source of health risk throughout the world. The potential health benefits of various medicinal plants and natural products in relation to protect various diseases are currently receiving considerable attention. A current approach is to develop a new biological compound from natural products that inhibits pain. Ethnopharmacological surveys have been found to be one of the most reliable tools for the discovery of the natural and semi-synthetic drug. The present study was performed to investigate the hematological and biochemical changes induced by carbendazim (CBZ) and the potential protective effect of seeds extracts of Nigella sativa (NSSE) and Foeniculum vulgare (FVSE) against CBZ toxicity in male mice. Mice were distributed into 6 groups. Mice of group 1 were served as control. Group 2 was exposed to CBZ. Group 3 was supplemented with NSSE and exposed to CBZ. Group 4 was treated with FVSE and CBZ. Normal mice of group 5 and 6 were subjected to NSSE and FVSE respectively. Body weight gain was significantly decreased in mice of group 2. In mice of group 2, significant declines of RBC, HB, Hct, WBC, total protein, FSH, LH, testosterone, T4, T3, CAT and SOD were observed. Moreover, the levels of ALT, AST, ALP, total bilirubin, creatinine, BUN, uric acid, glucose, cholesterol, CK, LDH, MDA and GSH were significantly enhanced. Treatment with NSSE and FVSE showed attenuation effects against CBZ induced hematological and biochemical changes. The results suggest that the attenuation effects of NSSE and FVSE attributed to their antioxidant properties.

Chronic Intake of Green Propolis Negatively Affecting the Rat Testis

BACKGROUND

Human and animal evidence suggests that environmental toxicants may have an adverse impact on male reproductive health, reducing the population's reproductive output. Owing to the renewed attraction for natural products, some of them constitute effective alternatives to mitigate these effects. Propolis is a candidate for this use because of its intrinsic properties. In many situations, it improved the testicular damage and alleviated the toxic effects induced by environmental contaminant exposure.

OBJECTIVE

The aim of this study was to investigate possible alterations of testicular parameters and certify if its use is really advantageous to the testis, since this could affect rat reproductive function.

MATERIALS AND METHODS

Forty-eight adult male Wistar rats were divided into four groups (Co = control, T1 = 3 mg propolis/kg/day, T2 = 6 mg/kg/day, T3 = 10 mg/kg/day) and were exposed during 56 days. The testes were assessed with morphometrical, stereological, and ultrastructural analyses. Cell proliferation and death were diagnosed, respectively, by immunocytochemistry. Connexin 43 (Cx43) and N-cadherin transcript levels were determined by reverse transcription-polymerase chain reaction.

RESULTS

Increased cell proliferation and Leydig cell volume were observed in T2, and in contrast, Cx43 upregulation and cell death were observed in T3. Both T2 and T3 showed ultrastructural abnormalities in testicular parenchyma.

CONCLUSION

We recommend a cautious intake of propolis to avoid deleterious effects.

SUMMARY

Chronic intake of Brazilian green propolis induced N.-cadherin downregulation and decreased on seminiferous tubule volumeIncrease on connexin 43 expression and cell death and decrease in Leydig cell.(LC) number/testis with the concentration of 10 mg/kg/day were observedIncrease on cell proliferation, cytoplasmic proportion, and volume of LC with the concentration of 6 mg/kg/day was detectedThe presence of empty spaces between spermatids and malformed spermatozoa in the lumen of seminiferous tubule was showedThis male reproductive disruption can be linked to phenolic compounds present in Brazilian green propolis. Abbreviation Used: AEC: 3-amino-9-ethylcarbazole; AJ: Adherens junction; AME: Aromadendrin-40-methyl ether; CAPE: Caffeic acid phenethyl ester; Co: Control group; C×43: Connexin 43; DAB: Diaminobenzidine; dNTP: Deoxyribonucleotide phosphate; DSP: Daily sperm production; FA: Ferulic acid; FSH: Follicle-stimulating hormone; GJ: Gap junction; GJIC: Gap junction intercellular communication; HPLC: High-performance liquid chromatography; LC: Leydig cell; LH: Luteinizing hormone; N-cad: N-cadherin; PCNA: Proliferating cell nuclear antigen; PCR: Polymerase chain reaction; RT-PCR: Reverse transcription-polymerase chain reaction; SDM: Standard deviation of mean; T1: Group exposed to 3 mg of propolis/kg/day; T2: Group exposed to 6 mg of propolis/kg/day; T3: Group exposed to 10 mg of propolis/kg/day; TUNEL: Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling; WB-ras 2 cells: Ras-transformed rat liver epithelial cell line.

Endocrine Disruptors in Domestic Animal Reproduction: A Clinical Issue?

Contents The objective of this review was to discuss whether endocrine disruption is a clinical concern in domestic animal reproduction. To that end, we firstly summarize the phenomenon of endocrine disruption, giving examples of the agents of concern and their effects on the mammalian reproductive system. Then there is a brief overview of the literature on endocrine disruptors and domestic animal reproduction. Finally, the clinical implications of endocrine disruptors on the reproductive system of farm animals as well as in dogs and cats are discussed. It is concluded that the evidence for clinical cases of endocrine disruption by chemical pollutants is weak, whereas for phytooestrogens, it is well established. However, there is concern that particular dogs and cats may be exposed to man-made endocrine disruptors.

A systematic review on the effects of environmental exposure to some organohalogens and phthalates on early puberty

Background:

Early puberty is a common worldwide problem. Different parameters as genetics, metabolic diseases, obesity, as well as environmental factors may affect the age of puberty. This systematic review aims to survey the related literature on the effects of environmental pollutants and especially organohalogens and phthalates on early puberty.

Materials and Methods:

A systematic review of papers published in the English language was completed in January 2014. Studies on the associations of organohalogens and phthalates with the puberty time were included. A literature search was conducted in EMBASE, PubMed, Scopus, ISI Web of Science, and Cochrane Library from 1995 to January 2014; moreover manual search through references of relevant manuscripts was considered. The literature search identified 212 papers, of which 13 papers fulfilled the inclusion criteria of the current study. Two reviewers independently identified relevant papers for potential inclusion and assessed the methodological quality.

Results:

This review included 6572 participants in nine countries from three continents (Europe, North America, and Asia). Different studies determined the effects of pollutants on maturation signs and pubertal stages and confirmed the association of organohalogens and phthalates with early puberty.

Conclusion:

Based on the studied literature, environmental pollutants surround and accumulate in human societies and their adverse health effects are well documented. It can be concluded that organohalogens and phthalates are disturbing the normal process of puberty timing; especially their influence on early maturation in girls should be underscored.

Comparative proteomic profiling and possible toxicological mechanism of acute injury induced by carbon ion radiation in pubertal mice testes

We investigated potential mechanisms of acute injury in pubertal mice testes after exposure to carbon ion radiation (CIR). Serum testosterone was measured following whole-body irradiation with a 2Gy carbon ion beam. Comparative proteomic profiling and Western blotting were applied to identify potential biomarkers and measure protein expression, and terminal dUTP nick end-labeling (TUNEL) was performed to detect apoptotic cells. Immunohistochemistry and immunofluorescence were used to investigate protein localization. Serum testosterone was lowest at 24h after CIR, and 10 differentially expressed proteins were identified at this time point that included eIF4E, an important regulator of initiation that combines with mTOR and 4EBP1 to control protein synthesis via the mTOR signaling pathway during proliferation and apoptosis. Protein expression and localization studies confirmed their association with acute injury following exposure to CIR. These three proteins may be useful molecular markers for detecting abnormal spermatogenesis following exposure to environmental and therapeutic radiation.

Investigation of effects of myricetin on thyroid-gonadal axis of male rats at prepubertal period

The present study is to investigate the effects of myricetin on pubertal development and thyroid hormone concentrations in the male rat. The rats were exposed to 25 and 50mg/kg/day of myricetin by gavage from post natal day (PND) 23 to 53. Preputial separation (PPS), organ weights and biochemical and hormone analysis were investigated. PPS was significantly delayed in low dose myricetin groups. Total serum thyroxine (T4) and, triiodothyronine (T3) levels increased in 25mg/kg myricetin dose group but thyroid-stimulating hormone (TSH) level increased in 0.7 μg/kg/day ethinyl estradiol dose groups. Myricetin exposure did not significantly change androgen dependent tissue weights; however myricetin exposure caused congestion, germinal cell debris and tubular atrophy in testis colloidal and tubular degeneration in thyroid gland were observed while there was germinal cell debris in epididymis. This study demonstrated that orally gavages myricetin caused adverse effects on male thyroid-gonadal axis during peripubertal period to pubertal period.

Leydig cell number and sperm production decrease induced by chronic ametryn exposure: a negative impact on animal reproductive health

Ametryn is an herbicide used to control broadleaf and grass weeds and its acute and chronic toxicity is expected to be low. Since toxicological data on ametryn is scarce, the aim of this study was to evaluate rat reproductive toxicity. Thirty-six adult male Wistar rats (90 days) were divided into three groups: Co (control) and T1 and T2 exposed to 15 and 30 mg/kg/day of ametryn, respectively, for 56 days. Testicular analysis demonstrated that ametryn decreased sperm number per testis, daily sperm production, and Leydig cell number in both treated groups, although little perceptible morphological change has been observed in seminiferous tubule structure. Lipid peroxidation was higher in group T2, catalase activity decreased in T1 group, superoxide dismutase activity diminished, and a smaller number of sulphydryl groups of total proteins were verified in both exposed groups, suggesting oxidative stress. These results showed negative ametryn influence on the testes and can compromise animal reproductive performance and survival.