Effects of escitalopram treatment and chronic mild stress induced from peripuberty on spermatic parameters of adult rats

BACKGROUND

The prevalence of depression in adolescents has significantly increased worldwide. Escitalopram is a selective serotonin reuptake inhibitor approved for treatment of psychiatric disorders in children and adolescents by the Food and Drugs Administration.

AIMS

This study aimed to evaluate the sperm parameters of adult rats exposed to chronic mild stress (CMS), from peripuberty to adulthood, treated or not with escitalopram.

MATERIALS AND METHODS

Sixty-two male rats were distributed into four groups: S - submitted to CMS; E - Escitalopram (10 mg / kg, via gavage); ES - CMS + ES; SC - Sham control. The induced depression protocol consisted of the exposure of the animals to nine different stressors (one stressor/day), randomly for 8 weeks, from peripuberty (41 days postpartum, dpp) to adulthood (97 dpp). The escitalopram treatment period started at 70 dpp and lasted 4 weeks. The euthanasia was performed for biological material collection at 114 dpp. Morphometric, biometric, sperm parameters, oxidative stress analyses, and corticosterone dosage were carried out.

RESULTS

There was a reduction of the sperm daily production and sperm concentration in the epididymis of rats treated and/or submitted to CMS. These groups (E, S, ES) also showed reduction of the mitochondrial activity; acrosome integrity; sperm chromatin compaction; sperm motility and vitality, besides an increased frequency of morphologically abnormal sperm. The sperm transit time through the epididymis was significantly higher in the escitalopram-treated rats (E, ES). No differences were observed regarding the sperm DNA fragmentation. The lipid peroxidation was significantly increased at the epididymal (E, S, and ES group) and testicular levels (S group).

CONCLUSION

The CMS with or without escitalopram treatment altered the oxidative status in sperm and male organs, worsening the qualitative and quantitative sperm parameters, which can probably compromise the male fertility.

Transcriptomics and proteomics analysis to explore the mechanism of Yishen Tongluo formula repairing sperm DNA damage in rats

The sperm DNA fragmentation index (DFI) is an objective indicator of male fertility. Currently, effective treatments for high sperm DFI are limited and traditional Chinese medicine (TCM) has certain advantages in this aspect. Yishen Tongluo formula (YSTL), a TCM formula, has been found to reduce DFI in patients. To better understand the mechanisms underlying its activity, we used transcriptomics and proteomics to analyse the potential target gene YSTL repairing tripterygium glycosides (TGs)-mediated sperm DNA damage in rats, followed by validation analyses using RT-qPCR and western blotting, which showed that relative to the control group, DFI was markedly elevated in the TGs group, but markedly lower in the YSTL group relative to the TGs group. KEGG pathway analysis of 119 differentially expressed genes and 158 DEPs identified using trend analysis revealed that they were enriched for apoptosis and base excision repair at the transcriptomic level and for microRNAs in cancer and complement and coagulation cascades at the proteomic level. Ttr and Pnpla2 were identified as potential target genes for YSTL. Our data show that YSTL can protect rat sperm DNA from TGs-induced damage, which may be related to apoptosis, DNA repair and other pathways, and the possible target genes are Ttr and Pnpla2.

Increased sperm DNA damage leads to poor embryo quality and subfertility of male rats treated with methylphenidate hydrochloride in adolescence

BACKGROUND

Methylphenidate hydrochloride (MPH) is a psychostimulant widely used in the treatment of attention deficit hyperactive disorder (ADHD), as well as a performance enhancer, for at least 60 years. Despite the notable effectiveness as a psychostimulant, ADHD is a chronic disorder and has a two-third chance of accompanying the individual throughout life. Long-term use of MPH has been associated not only with an increase in the development of neurodegenerative diseases, but it also has side effects on male fertility in experimental animals.

OBJECTIVES

To investigate whether methylphenidate poses a risk to sperm DNA structure and to the quality of embryos conceived after treatment during adolescence in rats.

MATERIALS AND METHODS

Wistar rats at 38 days of age were treated either with 5 mg/kg body weight of MPH, in a single daily dose for 30 days, via gavage or with distilled water-only protocol. Levels of oxidative stress in testicular and epididymal tissues were evaluated. Sperm chromatin quality and acrosome integrity was assessed under flow cytometry. From 107 days of age, animals were mated with untreated females. The effects of the paternal contribution at two different embryo development moments - cleavage stage (2.5 days post coitum) and late gestation (20 days post coitum) - were analyzed.

RESULTS

MPH caused high levels of sperm DNA damage, which was reflected in 40% of decrease in early embryo quality and a lower number of live pups at 20 dpc.

DISCUSSION

The high level of fragmentation seen in the embryos sired from the MPH group is consistent with the poor chromatin structure of the sperm, and does not seem to be a result of oxidative stress in the reproductive tissues.

CONCLUSIONS

The results presented here suggest that the subchronic use of MPH during male prepubertal phase may cause long term subfertility and compromise embryo survival. This article is protected by copyright. All rights reserved.

Protective effect of melatonin on alleviating early oxidative stress induced by DOX in mice spermatogenesis and sperm quality maintaining

Doxorubicin (DOX) is an effective chemotherapy drug, but its clinical use has adverse effects on male reproduction. However, there are few studies about the specific biological processes related to male reproduction or strategies for improving fertility protection. In this paper, we examined the effects of DOX on spermatogenesis and sperm function, and tested the possible protective role of melatonin (MLT) against DOX's reproductive toxicity. DOX-treated mice showed signs of significantly impaired spermatogenesis, including vacuolated epithelial cells, decreased testis weights, and lowered sperm counts and motility. DOX also reduced germ cell proliferation (PCNA) and meiosis-related proteins (SYCP3), but this effect could be partially improved with MLT administration. HSPA2 expression was maintained, which indicated that although MLT did not improve sperm motility, it did have a significant protective effect on elongated sperm. IVF results showed that MLT could partially promote two-cell and blastocyte development that was restricted by DOX. MLT reversed DOX-driven changes in the testes, including the antioxidant indices of SOD1, CAT and PRDX6, and the apoptotic indices of BAX and Caspase3. These results suggest that MLT effectively prevents DOX-induced early reproductive toxicity, and increase our understanding of the molecular mechanisms underlying DOX's effects on male reproduction and the protective mechanism of MLT.

Ephedra herb reduces adriamycin-induced testicular toxicity by upregulating the gonadotropin-releasing hormone signalling pathway

OBJECTIVE

We investigated the protective effects of ephedra herb (HEPH) on adriamycin-induced testicular toxicity in rats and explored the potential mechanisms underlying these effects.

METHODS

A rat model of adriamycin injury was established, and sperm motility-related indicator and oxidative stress levels in the testis were evaluated. Serum levels of sex hormones and levels of testicular cell apoptosis were detected by enzyme-linked immunosorbent assay and flow cytometry, respectively. Western blotting (WB), immunofluorescence analyses, and reverse transcription-polymerase chain reaction (RT-PCR) were performed to evaluate the gonadotropin-releasing hormone (GnRH) signalling pathway- and meiosis-related genes and proteins. In subsequent in vitro experiments, adriamycin was used to stimulate GC-1 cells, which were treated with HEPH, ephedrine, or pseudoephedrine. Cell viability was assessed using flow cytometry to detect apoptosis and reactive oxygen species, whereas the GnRH signalling pathway and levels of meiosis-related genes and proteins were evaluated by InCell WB, a high-content imaging system, and RT-PCR.

RESULTS

Per in vivo experiments, HEPH restored testicular weight and function, sperm characteristics, serum and tissue hormonal levels, and antioxidant defences and significantly activated the GnRH signalling pathway- and meiosis-related protein levels. All protective effects of HEPH against adriamycin-induced injury were antagonised by the GnRH antagonist cetrorelix. In vitro, HEPH, ephedrine, and pseudoephedrine significantly reduced adriamycin-induced GC-1 cell apoptosis and reactive oxygen species levels and increased the expression of GnRH signalling pathway- and meiosis-related proteins. The effect of pseudoephedrine was greater than that of ephedrine, and these findings may be an important basis for understanding the effects of HEPH.

Resveratrol benefits on sperm DNA, chromatin structure and reproductive outcomes of varicocelized rats

In varicocele, the main cause of sperm DNA damage is oxidative stress (OS). Resveratrol, a polyphenol with antioxidant properties, can protect cells from injuries caused by OS. We investigated the benefits of resveratrol against reproductive damage caused by experimental varicocele induced from peripuberty. Eighty peripubertal male rats were distributed into 4 groups: sham-control (S), varicocele (V), resveratrol (R) and varicocele treated with resveratrol (VR). Varicocele was induced through the partial ligature of the left renal vein. Resveratrol was given in a daily dose of 300 mg/kg body weight (gavage). Sperm samples were collected at 100 days of age for vitality, DNA fragmentation and chromatin protamination evaluations. OS analyses were carried out. Rats from all groups were mated with healthy primiparous females for evaluation of reproductive capacity and embryonic quality. The V group showed reduction of sperm vitality, altered chromatin protamination and sperm DNA integrity and high levels of OS. The VR group showed an improvement of oxidative status, sperm vitality, DNA integrity and chromatin structure, and an enhancement in the gestational index and embryonic quality. Therefore, we showed in this experimental model that resveratrol is a promising nutraceutical adjuvant and should be deeply studied to mitigate subfertility in varicocele.

Does maternal exposure to nicotine affect the oocyte quality and reproductive capacity in adult offspring?

Gonadal development begins in the intrauterine phase and females from most species are born with an established oocyte reserve. Exposure to drugs during gestation can compromise the offspring health, also affecting the gametes quality. Nicotine, the main component of cigarettes, is an oxidant agent capable of altering the fertility in men and women. As female gametes are susceptible to oxidative stress, this drug can damage the oolemma and affect oocyte maturation, induce errors during chromosomal segregation and DNA fragmentation. Oocyte mitochondria are particularly susceptible to injuries, contributing to the oocyte quality loss and embryonic development disruption. Thus, considering the high number of women who smoke during pregnancy, while significant events are occurring in the embryo for future fertility of offspring, we seek to verify the quality of the oocytes from adult rats exposed to nicotine during intrauterine phase and breastfeeding. Pregnant Wistar rats received nicotine by osmotic mini-pumps and the female progenies were evaluated in adulthood for oocyte quality (viability, lipid peroxidation, generation of reactive oxygen species and mitochondrial integrity) and reproductive capacity. Embryos (3dpc) and fetuses (20dpc) generated by these rats were also evaluated. The results showed that the dose of 2 mg/kg/day of nicotine through placenta and breast milk does not affect the number of oocytes and the fertility capacity of adult rats. However, it causes some morphological alterations in oocytes, mitochondrial changes, embryonic fragmentation and disruption of fetal development. The malformations in fetuses generated from these gametes can also indicate the occurrence of epigenetic modifications.

Tert-butylhydroquinone attenuates doxorubicin-induced dysregulation of testicular cytoprotective and steroidogenic genes, and improves spermatogenesis in rats

Doxorubicin (DOX) is a broad-spectrum chemotherapeutic drug used in the treatment of cancers. It acts by generating reactive oxygen species in target cells. The actions are, however, not limited to cancerous cells as it attacks healthy cells, killing them. This study investigated the benefits of the antioxidant, tert-butylhydroquinone (tBHQ), on testicular toxicity following DOX therapy. Twenty-four adult male albino rats were assigned randomly into four groups (n = 6), namely: normal control (NC), tBHQ, DOX and tBHQ + DOX groups. tBHQ (50 mg/kg body weight in 1% DMSO) was administered orally for 14 consecutive days, while a single DOX dose (7 mg/kg body weight) was administered intraperitoneally on Day 8. DOX decreased sperm count, motility and viability, and decreased the levels of steroidogenesis-related proteins, and reproductive hormones. Furthermore, DOX decreased the expression of antioxidant cytoprotective genes, and decreased the protein level of proliferating cell nuclear antigen in the testis. Conversely, DOX increased the expression of pro-inflammatory and pro-apoptotic genes in the testis. These negative effects were ameliorated following the intervention with tBHQ. Our results suggest that tBHQ protects the testis and preserves both steroidogenesis and spermatogenesis in DOX-treated rats through the suppression of oxidative stress, inflammation and apoptosis.

Resveratrol improves sperm DNA quality and reproductive capacity in type 1 diabetes

BACKGROUND

In the coming decades, diabetes mellitus might affect 628 million individuals. Its final impact on male fertility and reproductive outcomes should be considered since the number of adolescents and young adults presenting diabetes is rising. Resveratrol (RES), a polyphenol, is a biological modulator with multitarget and multi-action characteristics.

OBJECTIVES

to evaluate if RES is effective against the male reproductive damage caused by type 1 diabetes (DM1), focusing on sperm DNA integrity and reproductive outcome.

MATERIALS AND METHODS

At 30 dpp (days postpartum), male rats were divided into 7 groups: Sham control (SC); RES vehicle (RV); RES (R); STZ-diabetic (D; induced at 30dpp with 65 mg/kg of streptozotocin); STZ-diabetic + insulin (DI); STZ-diabetic + RES (DR); STZ-diabetic + insulin +RES (DIR). DR, DIR, and R groups received 150mg RES/kg b.w./day by gavage (from 33 to 110dpp). DI and DIR received insulin (from day 5 after DM1 induction until 110dpp). Blood glucose was monitored in different time points. Animals were mated with healthy females. Euthanasia occurred at 110 dpp.

RESULTS

DM1 increased lipid peroxidation (testis and epididymis) and sperm DNA fragmentation, alterations of chromatin structure, reduced mitochondrial mass and acrosome integrity, causing a decline in fertility and pregnancy rates. RES improved the parameters.

DISCUSSION

RES, as an adjuvant, activates specific reactions against hyperglycemia, the main trigger of most complications of diabetes, by controlling oxidative stress, probably as a result of SIRT1 activation. We present here more evidences showing its valuable role in diminishing diabetes seriousness to male reproduction, not only to spermatogenesis in the first instance, but also to sperm overall quality and fertility outcomes, regardless of insulin treatment.

CONCLUSION

RES attenuated lipid peroxidation and sperm DNA damage in DM1-induced animals, which positively reflected on male fertility. Our results show RES potential against DM1 complications in male reproduction.

Paradoxical risk of reduced fertility after exposure of prepubertal mice to vincristine or cyclophosphamide at low gonadotoxic doses in humans

Cancer treatment can have long-term side effects in cured patients and infertility is one of them. Given the urgency of diagnosis in children with cancer, the toxicity of treatments on the gonad was overshadowed for a long time. In the present study, prepubertal mice were treated by vincristine or cyclophosphamide commonly used in acute leukaemia treatment. The prepubertal exposure to cyclophosphamide, at a low gonadotoxic dose in humans (< 3.5 g/m²), led to morphological alterations of prepubertal testicular tissue. An increased proportion of spermatozoa with hypocondensed chromatin and oxidized DNA associated with decreased fertility were uncovered at adulthood. Short- and long-term morphological alterations of the testicular tissue, disturbed progression of spermatogenesis along with increased proportions of isolated flagella and spermatozoa with fragmented DNA were evidenced in vincristine-treated mice. Moreover, the fertility of mice exposed to vincristine was severely affected despite being considered low-risk for fertility in humans. Paternal exposure to vincristine or cyclophosphamide before puberty had no impact on offspring development. Contrary to the current gonadotoxic risk classification, our results using a mouse model show that vincristine and cyclophosphamide (< 3.5 g/m²) present a high gonadotoxic risk when administered before the initiation of spermatogenesis.

Carnitine Diminishes Etoposide Toxic Action on Spermatogonial Self-renewal and Sperm Production in Adult Rats Treated in the Prepubertal Phase

The aim of this study was to investigate carnitine action against negative effects of etoposide on stem/progenitor spermatogonia and on sperm production. Carnitine (250 mg/kg body weight/day) and etoposide (5 mg/kg body weight/day) were administered from 25-days postpartum to 32-days postpartum. Testes were collected at 32-days postpartum, 64-days postpartum, and 127-days postpartum, and submitted to the immuno-labeling of UTF1, SOX2, and PLZF proteins to identify undifferentiated spermatogonia populations. At 127-days postpartum, sperm were collected for analysis. Carnitine+etoposide group showed a higher numerical density of spermatogonia labeled for all studied proteins at 64-days postpartum (critical age) compared to the etoposide group. Moreover, there was an improvement of spermatic parameters and sperm DNA integrity in rats of the carnitine+etoposide group in comparison with rats of the etoposide group. The results suggest that carnitine improves the self-renewal of undifferentiated spermatogonia and promotes a partial protection on them, alleviating the etoposide harmful late effects and leading to an enhancement of the sperm parameters in adulthood.

Exposure to Chemotherapy During Childhood or Adulthood and Consequences on Spermatogenesis and Male Fertility

Over the last decade, the number of cancer survivors has increased thanks to progress in diagnosis and treatment. Cancer treatments are often accompanied by adverse side effects depending on the age of the patient, the type of cancer, the treatment regimen, and the doses. The testicular tissue is very sensitive to chemotherapy and radiotherapy. This review will summarize the epidemiological and experimental data concerning the consequences of exposure to chemotherapy during the prepubertal period or adulthood on spermatogenic progression, sperm production, sperm nuclear quality, and the health of the offspring. Studies concerning the gonadotoxicity of anticancer drugs in adult survivors of childhood cancer are still limited compared with those concerning the effects of chemotherapy exposure during adulthood. In humans, it is difficult to evaluate exactly the toxicity of chemotherapeutic agents because cancer treatments often combine chemotherapy and radiotherapy. Thus, it is important to undertake experimental studies in animal models in order to define the mechanism involved in the drug gonadotoxicity and to assess the effects of their administration alone or in combination on immature and mature testis. These data will help to better inform cancer patients after recovery about the risks of chemotherapy for their future fertility and to propose fertility preservation options.

Sperm DNA integrity in adult survivors of paediatric leukemia and lymphoma: A pilot study on the impact of age and type of treatment

Childhood cancer survivors (CCS) are more likely than siblings to report low sperm count and to use assisted reproductive technologies. Yet, it is still unclear if the sperm produced many years after remission of cancer display DNA and chromatin damage linked to male infertility and poor embryo development. As well, the importance of the age at diagnosis in relation to puberty is poorly understood. In this pilot study, we compared reproductive parameters and sperm damage from adult survivors of childhood leukemia and lymphoma, sub-divided into those diagnosed before or after puberty, to men with no history of cancer. Our data indicate that CCS, independently of the age of diagnosis, have a high risk of low sperm count and when sperm are present, chances of DNA and chromatin abnormalities appear similar to those seen in the general population. Exposure to alkylating agents is correlated with low sperm count whereas exposure to anthracyclines, and doxorubicin in particular, could have long-term consequences on sperm integrity. This study highlights the need for further research on fertility among male CCS and the importance of informing families about the potential long-term impact of chemotherapy on male fertility regardless of age at diagnosis.

Functional role of GKAP1 in the regulation of male germ cell spontaneous apoptosis and sperm number

G kinase-anchoring protein 1 (GKAP1) is a G kinase-associated protein that is conserved in many eutherians and is mainly expressed in the testis, especially in spermatocytes and round spermatids. The function of GKAP1 in the testis is largely unknown. Here, we revealed that deletion of GKAP1 led to an increase in sperm production with swollen epididymis, and germ cell apoptosis was found to decrease in GKAP1 knock-out mice. Further investigations showed that a deficiency of GKAP1 could partly change the cellular location of cGK-Iα and increase the amount of active cAMP response element-binding protein (CREB) in the nucleus. Therefore, the expression of a particular inhibitor of apoptosis proteins (IAPs) was upregulated because of the activation of CREB, and this increase in IAPs was associated with a decrease in the level of activated caspase-3. These results suggest that a deficiency of GKAP1 in mouse testis could increase sperm production through a reduction of the spontaneous apoptosis of germ cells in the testis, possibly because of a change in the activity of the cGK-Iα pathway.

Fluvastatin attenuates doxorubicin-induced testicular toxicity in rats by reducing oxidative stress and regulating the blood–testis barrier via mTOR signaling pathway

Doxorubicin (DOX) is an anthracycline derivative antibiotic that still frequently used in the treatment of solid tumors and hematological malignancies. The clinical use of DOX is largely restricted due to acute and chronic renal, cardiac, hematological, and testicular toxicities. Previous studies have indicated that oxidative stress, lipid peroxidation, and apoptosis in germ cells are the main factors in DOX-induced testicular toxicity, but the entire molecular mechanisms that responsible for DOX-induced testicular damage are not yet fully understood. Fluvastatin is a cholesterol-lowering agent that acts by inhibiting hydroxylmethyl glutaryl coenzyme A, the key enzyme for cholesterol biosynthesis. In addition to its cholesterol-lowering effect, fluvastatin showed an antioxidant effect by cleaning hydroxyl and superoxide radicals and this drug could have a protective effect by acting on the mammalian target of rapamycin (mTOR) signal pathway in testicular damage caused by obesity. This study aimed to investigate the possible protective and therapeutic effects of fluvastatin on the DOX-induced testicular toxicity model by histochemical, immunohistochemical, biochemical, and real-time polymerase chain reaction analyses. The present study indicates that fluvastatin may have a protective and therapeutic effect by removing reactive oxygen species and by regulating the mTOR, connexin 43, and matrix metalloproteinase 9 protein and messenger ribonucleic acid expressions, which play an important role in regulating the blood–testis barrier. On the other hand, the use of fluvastatin as a protective/prophylactic agent was found to be more effective than the use of this drug for treatment. In light of this information, fluvastatin may be a candidate agent that can be used to prevent testicular toxicity observed in men receiving DOX treatment.

Sperm DNA Damage in Cancer Patients

Fertility is a growing healthcare issue for a rising number of cancer survivors. In men, cancer itself and its treatment can negatively affect spermatogenesis by targeting the dividing spermatogonia and their cellular environment, ultimately leading to a reduction of testicular germ cells and sperm count. Experimental data and prospective longitudinal studies have shown that sperm production can recover after cancer treatment. But despite this, yet unpredictable, recovery in sperm production, cancer survivors are more at risk to produce sperm with aneuploidy, DNA damage, abnormal chromatin structure, and epigenetic defects even 2 years post-treatment. Sperm DNA alteration is of clinical concern, as these patients may father children or seek assisted reproduction technologies (ART) using gametes with damaged genome that could result in adverse progeny outcomes. Interestingly, large cohort studies revealed lower birth rate but no significant impact on the health of the children born from male cancer survivors (naturally or using ART). Nevertheless, a better understanding of how cocktail of chemotherapy and new anticancer agents affect spermatogenesis and sperm quality is needed to reduce side effects. Moreover, developing new fertility preservation strategies is essential as sperm cryopreservation before treatment is currently the only option but does not apply for prepubertal/young postpubertal patients.

Vitamin B12 Prevents Cimetidine-Induced Androgenic Failure and Damage to Sperm Quality in Rats

Cimetidine, used as an anti-ulcer and adjuvant treatment in cancer therapy, causes disorders in the male reproductive tract, including steroidogenesis. However, its effect on sperm quality and male fertility has been poorly addressed. Since vitamin B₁₂ has demonstrated to recover spermatogonia number and sperm concentration in cimetidine-treated rats, we evaluated the impact of cimetidine on sperm quality and fertility potential and whether vitamin B₁₂ is able to prevent the harmful effect of this drug on steroidogenesis and sperm parameters. Adult male rats were treated for 52 consecutive days as follows: cimetidine group (100 mg/kg of cimetidine), cimetidine/vitamin B₁₂ group (100 mg/kg of cimetidine + 3 μg vitamin B₁₂), vitamin B₁₂ group (3 μg vitamin B₁₂) and control group (saline). Serum testosterone levels and immunofluorescence associated to western blot for detection of 17β-HSD6 were performed. Sperm morphology and motility, mitochondrial activity, acrosome integrity, DNA integrity by Comet assay, lipid peroxidation as well as fertility potential were analyzed in all groups. Apoptotic spermatids were also evaluated by caspase-3 immunohistochemistry. In the cimetidine-treated animals, reduced serum testosterone levels, weak 17β-HSD6 levels and impaired spermiogenesis were observed. Low sperm motility and mitochondrial activity were associated with high percentage of sperm tail abnormalities, and the percentage of spermatozoa with damaged acrosome and DNA fragmentation increased. MDA levels were normal in all groups, indicating that the cimetidine-induced changes are associated to androgenic failure. In conclusion, despite the fertility potential of rats was unaffected by the treatment, the sperm quality was significantly impaired. Therefore, considering a possible sperm-mediated transgenerational inheritance, the long term offspring health needs to be investigated. The administration of vitamin B₁₂ to male rats prevents the androgenic failure and counteracts the damage inflicted by cimetidine upon sperm quality, indicating that this vitamin may be used as a therapeutic agent to maintain the androgenic status and the sperm quality in patients exposed to androgen disrupters.

How does chemotherapy treatment damage the prepubertal testis?

Chemotherapy treatment is a mainstay of anticancer regimens, significantly contributing to the recent increase in childhood cancer survival rates. Conventional cancer therapy targets not only malignant but also healthy cells resulting in side effects including infertility. For prepubertal boys, there are currently no fertility preservation strategies in use, although several potential methods are under investigation. Most of the current knowledge in relation to prepubertal gonadotoxicity has been deduced from adult studies; however, the prepubertal testis is relatively quiescent in comparison to the adult. This review provides an overview of research to date in humans and animals describing chemotherapy-induced prepubertal gonadotoxicity, focusing on direct gonadal damage. Testicular damage is dependent upon the agent, dosage, administration schedule and age/pubertal status at time of treatment. The chemotherapy agents investigated so far target the germ cell population activating apoptotic pathways and may also impair Sertoli cell function. Due to use of combined chemotherapy agents for patients, the impact of individual drugs is hard to define, however, use of in vivo and in vitro animal models can overcome this problem. Furthering our understanding of how chemotherapy agents target the prepubertal testis will provide clarity to patients on the gonadotoxicity of different drugs and aid in the development of cytoprotective agents.

Perturbation of microRNA signalling by doxorubicin in spermatogonial, Leydig and Sertoli cell lines in vitro

We have previously shown that in addition to its widely recognised cardiotoxicity, the chemotherapeutic doxorubicin (DOX) is able to induce transcriptional, microRNA (miRNA) and DNA methylation changes in the mouse testis. These changes perturb pathways involved in stress/cell death and survival and testicular function and lead to germ cell loss and reproductive organ damage. Here, we further investigated the differential miRNA expression induced by DOX in mouse spermatogonial (GC1), Leydig (TM3) and Sertoli (TM4) cell lines in vitro. We began by performing cell cycle analysis of the three mouse testicular cell lines to evaluate their sensitivity to DOX and thus select suitable doses for miRNA profiling. In keeping with our in vivo data, the spermatogonial cell line was the most sensitive, and the Sertoli cell line the most resistant to DOX-induced cell cycle arrest. We then further demonstrated that each cell line has a distinct miRNA profile, which is perturbed upon treatment with DOX. Pathway analysis identified changes in the miRNA-mediated regulation of specialised signalling at germ-Sertoli and Sertoli-Sertoli cell junctions following treatment with DOX. Amongst the most significant disease categories associated with DOX-induced miRNA expression were organismal injury and abnormalities, and reproductive system disease. This suggests that miRNAs play significant roles in both normal testicular function and DOX-induced testicular toxicity. Comparison of our in vitro and in vivo data highlights that in vitro cell models can provide valuable mechanistic information, which may also help facilitate the development of biomarkers of testicular toxicity and high-throughput in vitro screening methods to identify potential testicular toxicants.

Efeitos de sulfato de vincristine sobre os testículos de ratos albinos, tratados na fase pré-púbere

RESUMO: Este trabalho visou avaliar os efeitos de sulfato de vincristine sobre os testículos de ratos tratados na fase pré púbere, sobretudo quanto às alterações das células de Sertoli e das células germinativas. Foram utilizados 30 animais controles e 30 tratados com sulfato de vincristine. As aplicações da droga ocorreram aos 15 dias de vida, e a eutanásia aos 40, 64 e 127 dias de vida para possibilitar a avaliação em diferentes estágios de desenvolvimento reprodutivo. Foram realizadas medidas biométricas (pesos corpóreos e testiculares), medidas morfométricas testiculares, (eixos testiculares maiores e menores, diâmetros testiculares de túbulo e lúmen seminíferos, e altura do epitélio seminífero) e estereológicas (volumes testiculares e as densidades de volume do tecido tubular e do tecido intersticial testicular). As medidas biométricas foram feitas em todos os animais do experimento, e as avaliações morfométricas e estereológicas foram realizadas em 200 túbulos seminíferos. Os resultados demonstraram que sulfato de vincristine reduz parâmetros biométricos como peso corpóreo, peso testicular e volume testicular total. Variáveis morfométricas e estereológicas como diâmetro dos túbulos seminíferos, altura do epitélio seminífero e volume dos túbulos seminíferos também foram reduzidos. Os tipos celulares mais atingidos foram as espermatogônias, espermátides tardias e células de Sertoli.

In vitro study of doxorubicin-induced oxidative stress in spermatogonia and immature Sertoli cells

Pediatric chemotherapy treatments can impair long-term male fertility. Unfortunately, no fertility preservation solution is available for pre-pubertal boys. Studies suggest that doxorubicin, used against pediatric cancers, induces oxidative stress in the testis. However, the targeted testicular cell types remain unknown. The goal of this study was to determine whether doxorubicin can induce oxidative stress in rat spermatogonia (GC-6Spg) and immature Sertoli (Ser-W3) cell lines, and to assess their protection by antioxidants. Using the MTT assay, we have shown that doxorubicin induces a time- and dose-dependent cytotoxicity in these two cell lines, Ser-W3 being more sensitive than GC-6Spg. After 3 h of treatment, reactive oxygen species and nuclear 8-oxo-deoxyguanosine increase in Ser-W3, but not in GC-6Spg. Moreover, after 6 h of treatment, intracellular reduced glutathione levels decrease significantly in Ser-W3 cells. These results show that doxorubicin induces oxidative stress in the Ser-W3 cell line. However, a depletion in glutathione does not affect their survival, and supplementation only offers a weak protection after exposure to doxorubicin, suggesting that the glutathione system is not essential for Ser-W3 cell line's defense against doxorubicin. On the other hand, among four antioxidants selected from the literature, none reduces the cytotoxicity of doxorubicin in Ser-W3 cells. Together, our data suggest that oxidative stress may not be a major pathway for doxorubicin's cytotoxicity in GC-6Spg and Ser-W3 lines. This study provides new insights in the mechanisms by which chemotherapies affect the pre-pubertal testis, with the long-term goal to help improve the quality of life of pediatric cancer survivors.

[Transgenerational impact of chemotherapy: Would the father exposure impact the health of future progeny?]

The number of cancer survivors is increasing and their quality of life is becoming a major public health issue. Cancer treatments reduce men's reproductive health by targeting spermatogenesis. Ultimately, DNA, chromatin and the epigenome of spermatozoa can be altered in cancer survivors. Knowing whether the history of cancer and the treatments received can have consequences on the health of their offspring is therefore a fundamental question for these patients. This review gathers the experimental and epidemiological evidences of the effects observed on the direct descendants and on several generations, and draws up the state of knowledge on the mechanisms potentially involved. Experimental data describe inter- and transgenerational effects of paternal exposure depending on the type of treatment, dose and time of exposure. In the human population, the analysis of the effects specifically due to chemotherapy is still limited because they are often combined with irradiation treatments. However, it appears that chemotherapy agents affect the birth rate but do not have a significant impact on the health of the children born. Nevertheless, the demonstration of modifications of the sperm epigenome in cancer survivors, even after a period of remission, as well as changes in the sperm of the progeny in animal models, suggests a possible transgenerational transmission that remains to be studied in the human population.

Doxorubicin and vincristine affect undifferentiated rat spermatogonia

Anticancer drugs, such as alkylating agents, can affect male fertility by targeting the DNA of proliferative spermatogonial stem cells (SSC). Therefore, to reduce such side effects, other chemotherapeutics are used. However, less is known about their potential genotoxicity on SSC. Moreover, DNA repair mechanisms in SSC are poorly understood. To model treatments deprived of alkylating agents that are commonly used in cancer treatment, we tested the impact of exposure to doxorubicin and vincristine, alone or in combination (MIX), on a rat spermatogonial cell line with SSC characteristics (GC-6spg). Vincristine alone induced a cell cycle arrest and cell death without genotoxic impact. On the other hand, doxorubicin and the MIX induced a dose-dependent cell death. More importantly, doxorubicin and the MIX induced DNA breaks, measured by the COMET assay, at a non-cytotoxic dose. To elucidate which DNA repair pathway is activated in spermatogonia after exposure to doxorubicin, we screened the expression of 75 genes implicated in DNA repair. Interestingly, all were expressed constitutively in GC-6spg, suggesting great potential to respond to genotoxic stress. Doxorubicin treatments affected the expression of 16 genes (>1.5 fold change;P < 0.05) involved in cell cycle, base/nucleotide excision repair, homologous recombination and non-homologous end joining (NHEJ). The significant increase in CDKN1A and XRCC1 suggest a cell cycle arrest and implies an alternative NHEJ pathway in response to doxorubicin-induced DNA breaks. Together, our results support the idea that undifferentiated spermatogonia have the ability to respond to DNA injury from chemotherapeutic compounds and escape DNA break accumulation.

Resveratrol improves reproductive parameters of adult rats varicocelized in peripuberty

The aim of this study was to investigate the protective action of resveratrol against the reproductive damage caused by left-sided experimental varicocele. There was a reduction of testicular major axis in the varicocele group when compared with the other groups; the testicular volume was reduced in varicocele group in comparison to the sham–control and resveratrol groups. The frequency of morphologically abnormal sperm was higher in varicocele and varicocele treated with resveratrol groups than in sham–control and resveratrol groups. The frequency of sperm with 100% of mitochondrial activity and normal acrosome integrity were lower in varicocele group than in varicocele treated with resveratrol, sham–control and resveratrol groups. Sperm motility was also reduced in varicocele group than in other groups. The sperm DNA fragmentation was higher in varicocele group than in other groups. Testicular levels of malondialdehyde were higher in varicocele and varicocele treated with resveratrol groups. The varicocele and varicocele treated with resveratrol groups had a significantly higher frequency of TUNEL-positive cells than sham–control and resveratrol groups; however, immunolabeling of the testes from varicocele treated with resveratrol group showed a lower number of apoptotic germ cells in comparison with the left testis of rats of the varicocele group. Reproductive alterations produced by varicocele from peripuberty were reduced by resveratrol in adulthood. Resveratrol should be better investigated as an adjuvant in the treatment of varicocele. Daily administration of resveratrol to rats with varicocele from peripuberty improves sperm quality in the adulthood.

Perturbation of epigenetic processes by doxorubicin in the mouse testis

Epigenetic processes play a major role in normal mammalian development, particularly during gametogenesis and early embryogenesis. Thus, perturbation of epigenetic processes in the testis by xenobiotics could have a major impact on testicular function and fertility, and potentially affect the development and health of subsequent generations. There has been substantial research into the epigenetic toxicity of environmental exposures over the last decade. However, few studies have focussed on pharmaceutical drugs, which due to the nature of their use are typically found at much higher concentrations within exposed individuals than environmental chemicals. Here, we investigated genome-wide changes in testicular mRNA transcription, microRNA expression and DNA methylation to assess the contribution of epigenetic mechanisms to the testicular toxicity induced by doxorubicin (DOX) as a representative, widely used and well-characterised anti-cancer drug. We demonstrated that DOX is able to induce transcriptional, microRNA and DNA methylation changes, which perturb pathways involved in stress/cell death and survival and testicular function and lead to germ cell loss and reproductive organ damage. This identified potential novel mechanisms of DOX-induced testicular toxicity for further focussed investigations. Such work is required to fully assess the role of epigenetics in toxicity, determine whether single and/or multigenerational epigenetic toxicity is a real public health concern, and begin to develop and incorporate relevant epigenetic endpoints into regulatory toxicology.

Impact of lymphoma treatments on spermatogenesis and sperm deoxyribonucleic acid: a multicenter prospective study from the CECOS network

OBJECTIVE

To determine consequences of lymphoma treatments on sperm characteristics and sperm DNA, and to evaluate predictors of sperm recovery.

DESIGN

Multicenter prospective longitudinal study of patients analyzed before treatment and after 3, 6, 12, and 24 months.

SETTING

University hospitals.

PATIENT(S)

Seventy-five Hodgkin lymphoma and non-Hodgkin lymphoma patients and a control group of 257 fertile men.

INTERVENTION(S)

Semen analyses, and sperm DNA and chromatin assessments.

MAIN OUTCOME MEASURE(S)

Comparisons of sperm characteristics before and after treatment.

RESULT(S)

Patients already had altered sperm characteristics before lymphoma treatment, with no identified risk factor. Sperm count, total sperm count, motility, and vitality decreased after treatment, with lowest values at 3 and 6 months. Twelve months after treatment, mean sperm count recovered to pretreatment values after doxorubicin, bleomycin, vinblastine, darcarbacine (ABVD) or ABVD+radiotherapy, but not after doxorubicin, cyclophosphamide, vincristine, prednisone (CHOP) or mechlorethamine, oncovin, procarbazine, prednisone (MOPP) chemotherapies. It was noteworthy that 7% of patients remained azoospermic at 24 months. After 24 months, Kaplan-Meier estimates showed that more than 90% of patients will recover normal sperm count after ABVD or ABVD+radiotherapy vs. 61% for CHOP chemotherapies. In multivariate analyses including diagnosis and treatment protocol, only pretreatment total sperm count was related to recovery. Compared with a control group, lymphoma patients had higher sperm chromatin alterations and DNA fragmentation before any treatment. After treatment, DNA fragmentation assessed by TUNEL assay and sperm chromatin structure assay decreased from 3 and 6 months, respectively, while remaining higher than in the control group during follow-up.

CONCLUSION(S)

Lymphoma patients had altered sperm DNA and chromatin before treatment. Lymphoma treatment had damaging effects on spermatogenesis. These data on both the recovery period according to treatment modalities and the pre- and post-treatment chromatin status of sperm are useful tools for counseling patients wishing to conceive.

Reproductive function of the male obese Zucker rats: alteration in sperm production and sperm DNA damage

Obesity has been considered a public health issue in many countries and is of increasing concern for authorities over the past 6 years. The Zucker rat is a good experimental model for obesity and diabetes studies due to its metabolic characteristics that are similar to those developed by humans. A total of 12 obese Zucker rats and their lean littermates were killed in pubertal and young adult phases for assessing organ weights (testis and epididymis), testicular histomorphometric and stereological analyses, daily sperm production, and transit time in the epididymis. Sperm integrity was also investigated in the adult animals using the Comet assay. Alterations in organ weights, seminiferous epithelium architecture, sperm production, and transit time were noticed in the pubertal fatty rats. The volume density of the lymphatic space was decreased in both the ages. Adult animals had a significant increase in the extent of damage found in sperm DNA. Our results show for the first time that leptin receptor deficiency compromises sperm production during puberty and that genetic obese Zucker rats have increased sperm DNA fragmentation.