Prepubertal Mice Research Articles

Ethanolic extract of Moringa oleifera leaves alleviate cyclophosphamide-induced testicular toxicity by improving endocrine function and modulating cell specific gene expression in mouse testis

Ethnopharmacological relevanceMoringa oleifera Lam. is known for its nutritional and ethno medicinal values due to the presence of wide array of phytochemicals with multiple biological activities. We have previously reported that ethanolic extract of Moringa oleifera leaves (MOE) ameliorated cyclophosphamide (CP)-induced testicular toxicity and improved functional integrity of spermatozoa as well as spermatogenic cells. Aim of the studyThe present study was planned to investigate whether the mitigation of CP-induced testicular toxicity by MOE is mediated via modulation of endocrine profile, genes associated with function of different cell types and enhancement of DNA repair response in spermatogonial cells. Materials and methodsAdult Swiss albino mice (8 week) were injected with CP (100 mg/kg, one dose in a week for 3 weeks) and MOE (100 mg/kg, 5 doses in a week for 4 weeks) either alone or in combination intraperitoneally. At 35 day post CP injection (first dose), the functional characteristics such as count, motility, head morphology and DNA integrity were assessed in epididymal spermatozoa. Key reproductive hormones like testosterone, follicle stimulating hormone (FSH) and Inhibin B concentration were analyzed in serum and testis. In addition, mRNA expression of genes pertaining to the function of Leydig, Sertoli and spermatogonial cells as well as antioxidant enzymes were evaluated in the testis. To understand the DNA damage and repair process in germ cells, prepubertal (2 week) mice were administered with single dose of CP (200 mg/kg) and/or MOE (100 mg/kg) and analyzed for expression of DNA damage (γ-H2AX, P53 and Caspase3) and repair genes (Rad51 and Ku80) in isolated spermatogonial cells at various time points after treatment. ResultsCP administration resulted in decrease in count, motility and increase in morphological defects and DNA damage in spermatozoa. Testosterone level was marginally decreased while there was a significant increase in FSH (p < 0.001) and decrease in inhibin B (p < 0.05) observed in CP treated mice. Administration of MOE prior to CP, improved sperm functional characteristics, decreased FSH and increased inhibin B levels. Expression of Abp was down-regulated while Transferrin, Fshr and Gata4 (Sertoli cell specific genes) were up-regulated in testis treated with CP. Administration of CP down-regulated the expression of Oct4 and Ddx4 (Spermatogonia specific genes). MOE administration was shown to ameliorate CP-induced damage by modulating the expression of genes specific to Sertoli and spermatogenic cells. Furthermore, MOE treatment reduced CP-induced DNA damage as evident from lower percentage of γ-H2AX positive spermatogonial cells. ConclusionAdministration of MOE mitigated CP-induced testicular damage by improving blood and, intra-testicular hormonal milieu as well as modulating the expression of genes pertaining to Sertoli and spermatogonial cells.

SAT-595 Early Weight Gain Impact onto the Arcuate Leptin Receptor Expressing Neurons Activity During Development

The arcuate nucleus (ARH) is considered the main mediator of the effects of leptin on energy homeostasis, as well, part of the hypothalamic circuitry through which the sex steroids mediate the ovulatory cycle and therefore reproduction. While it is known that aging influences synaptic plasticity of ARH neurons, the effects of increased weight gain early in life onto in the activity of ARH neurons are still poorly understood. In order to demonstrate whether prepubertal adiposity gain is able to modulate the synaptic transmission in leptin receptor (LepR)-expressing cells of the ARH, we employed a postnatal over-nutrition model by raising mice in small litters (SL), while control mice were maintained in regular litters (6-8 pups per litter). The spontaneous currents of LepR-expressing neurons in the ARH were measured by whole-cell patch-clamp recordings in hypothalamic slices obtained from prepubertal, pubertal and adult female LepR-reporter mice. As expected, mice raised in SL exhibited increased body weight compared to control mice at prepubertal and pubertal stage (prepubertal, t(59) = 6.9, P < 0.001; pubertal, t(59) = 5.3, P < 0.001), despite no difference at adult age (t(59) = 1.5, P = 0.4). By evaluating ARH neuronal activity we observed an increased average of excitatory and inhibitory currents frequency during development, in both control females (sEPSC: F(2, 46)= 17.76, P< 0.0001, sIPSC: F(2, 21)= 4.064, P= 0.0322) and in mice raised in SL (sEPSC: F(2, 49)= 27.76, P< 0.0001, sIPSC: F(2, 19)= 6.714, P= 0.0062). However, SL and control mice exhibited similar sEPSC amplitudes at all stages of development. A significant interaction between litter size and excitatory transmission frequency onto LepR-expressing cells were noted at the pubertal and adult stages (F(2, 95)= 3.164, P= 0.046), despite no changes in the amplitudes of these signals (interaction: F(2, 95) = 0.1516, P= 0.8596; age: F(2, 95) = 0.9961, P= 0.3731; litter size: F(1, 95) = 0.076, P= 0.7832). By evaluating the inhibitory transmission to ARH LepR-expressing neurons, no significant interaction between litter size and inhibitory transmission frequency were observed (F(2, 40) = 0.09271, P= 0.9117). However, the average sIPSC amplitude were significantly reduced in the ARH cells recorded from mice raised in SL, when compared to the control group (F(2, 42) = 22.86, P< 0.0001), despite no identifiable interaction between litter size and inhibitory transmission (F(2, 42) = 0.6619, P= 0.5212). Taken together our results suggest that early weight gain influences the excitatory transmission pattern in LepR-expressing neurons by increasing presynaptic excitatory inputs and suppressing postsynaptically transmission to ARH neurons.

SAT-018 Androgen Actions in Adipose Tissue and the Brain Are Key Mediators in the Development of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a complex disorder characterised by endocrine, reproductive and metabolic abnormalities. Despite PCOS being the most common endocrinopathy affecting women of reproductive age, its etiology is poorly understood so there is no cure and symptom-oriented treatment is suboptimal. Elucidation of the underlying mechanisms involved in the pathogenesis of PCOS would pave the way for the development of new interventions for PCOS. Hyperandrogenism is the most consistent feature observed in PCOS patients, and recently aberrant neuroendocrine signalling and adipose tissue function have been proposed as playing a pathogenic role in the development of experimental PCOS. To investigate the role of adipose tissue and the brain as potential key sites for androgen receptor (AR)-mediated development of PCOS, we combined an adipocyte and brain-specific ARKO knockout (AdBARKO) mouse model with a dihydrotestosterone (DHT)-induced mouse model of PCOS. Wildtype (WT) and AdBARKO prepubertal mice were implanted with a blank or DHT implant and examined after 12 weeks. In WT control females, DHT exposure induced the PCOS reproductive traits of cycle irregularity, ovulatory dysfunction and reduced follicle health. In contrast, these reproductive features of PCOS were absent in DHT-treated AdBARKO females. The PCOS metabolic characteristics of increased adiposity, adipocyte hypertrophy and hepatic steatosis were induced by DHT in WT females. Despite DHT treatment, AdBARKO females displayed normal white adipose tissue weight, and adipocyte hypertrophy and hepatic steatosis were not evident. However, as with WT mice, DHT treatment induced increased fasting glucose levels in AdBARKO females. These results demonstrate that adipose tissue and the brain are key loci for androgen-mediated actions involved in the developmental origins of PCOS. These findings support targeting adipocyte and neuroendocrine AR-driven pathways in the future development of novel therapeutic strategies for PCOS.

Perinatal androgen exposure impacts mast cell development and mediator storage

Abstract Mast cell (MC)-associated diseases often exhibit a female sex bias in both prepubertal children and adults. We have shown that female MCs store and release greater amounts of histamine which correlates with heightened anaphylaxis in both prepubertal and adult mice. Further, perinatal androgen exposure, a major organizing event in sex biology, reduced MC histamine storage and release, and the severity of anaphylaxis in prepubertal and adult female mice, thus demonstrating that perinatal androgens are critical early life drivers of MC sex differences, but the mechanisms remain poorly understood. The objective of this study was to determine how perinatal androgens impact MC development. RNA sequencing analysis of BMMCs derived from adult female and male mice that were previously exposed to perinatal androgens revealed significant down-regulation of a number of genes related to granule biogenesis and mediator storage of which included lactotransferrin (by −2.6 fold), proteoglycan 2 (by −3.9 fold), lipocalin 2 (by −1.4-fold), elastase (by −2.5 fold) and myeloperoxidase (by 1.4 fold). Current studies aim to confirm RNA seq data with qPCR and protein expression analysis and to define the critical period of androgen programming on MC development and function. Understanding the mechanisms by which early life androgens drive sex differences in MCs will be critical in understanding the origins of sex differences in MC and its role in health and disease.

THE EFFECT OF COGON GRASS ROOT ETHANOL EXTRACT ON REPRODUCTIVE ORGAN AND EPIDIDYMAL SPERM QUALITY OF MOUSE WITH DIFFERENT AGES

This study aims to determine changes related to epididymal sperm parameters in mice given cogon grass root ethanol extract (CGREE). The experiment was carried out by dividing three groups of mice aged 4-week old (early pubertal), 8-week old (adult), and 24-week old (old) as control and treatment groups. The treatment groups were given 115 mg/kg body weight of CGREE for 14 days. The mice were sacrificed on day 15 to asses reproductive organ indexes and quality of the epididymal sperm. Index of epididymis and ductus deferens indices significantly reduced in the 4-week old treatment group compared to control (0.23 vs 0.33; 0.08 vs 0.16, respectively), and vesical seminal significantly reduced in 8- week old treatment group compared to control (0.76 vs 0.68). The epididymal sperm quality significantly decreased in all treatment groups, but the sperm concentration in early pubertal group showed an increase. These results indicate that CGREE can enhance several semen parameters in prepubertal and adult mice but this effect is not apparent in old mice.

MRBPome capture identifies the RNA-binding protein TRIM71, an essential regulator of spermatogonial differentiation.

Continual spermatogenesis relies on the actions of an undifferentiated spermatogonial population that is composed of stem cells and progenitors. Here, using mouse models, we explored the role of RNA-binding proteins (RBPs) in regulation of the biological activities of this population. Proteins bound to polyadenylated RNAs in primary cultures of undifferentiated spermatogonia were captured with oligo (dT)-conjugated beads after UV-crosslinking and profiled by proteomics (termed mRBPome capture), yielding a putative repertoire of 473 RBPs. From this database, the RBP TRIM71 was identified and found to be expressed by stem and progenitor spermatogonia in prepubertal and adult mouse testes. Tissue-specific deletion of TRIM71 in the male germline led to reduction of the undifferentiated spermatogonial population and a block in transition to the differentiating state. Collectively, these findings demonstrate a key role of the RBP system in regulation of the spermatogenic lineage and may provide clues about the influence of RBPs on the biology of progenitor cell populations in other lineages.

Gut microbiota manipulation during the prepubertal period shapes behavioral abnormalities in a mouse neurodevelopmental disorder model

Previous studies demonstrate an association between activation of the maternal immune system during pregnancy and increased risk of neurodevelopmental psychiatric conditions, such as schizophrenia and autism, in the offspring. Relatively recent findings also suggest that the gut microbiota plays an important role in shaping brain development and behavior. Here we show that maternal immune activation (MIA) accomplished by infection with a mouse-adapted influenza virus during pregnancy induced up-regulation of frontal cortex serotonin 5-HT2A receptor (5-HT2AR) density in the adult offspring, a phenotype previously observed in postmortem frontal cortex of schizophrenic subjects. 5-HT2AR agonist-induced head-twitch behavior was also augmented in this preclinical mouse model. Using the novel object recognition (NOR) test to evaluate cognitive performance, we demonstrate that MIA induced NOR deficits in adult offspring. Oral antibiotic treatment of prepubertal mice prevented this cognitive impairment, but not increased frontal cortex 5-HT2AR density or psychedelic-induced head-twitch behavior in adult MIA offspring. Additionally, gut microbiota transplantation from MIA mice produced behavioral deficits in antibiotic-treated mock mice. Adult MIA offspring displayed altered gut microbiota, and relative abundance of specific components of the gut microbiota, including Ruminococcaceae, correlated with frontal cortex 5-HT2AR density. Together, these findings provide a better understanding of basic mechanisms by which prenatal insults impact offspring brain function, and suggest gut-brain axis manipulation as a potential therapeutic approach for neurodevelopmental psychiatric conditions.

Loss of Cx43 in Murine Sertoli Cells Leads to Altered Prepubertal Sertoli Cell Maturation and Impairment of the Mitosis-Meiosis Switch.

Male factor infertility is a problem in today’s society but many underlying causes are still unknown. The generation of a conditional Sertoli cell (SC)-specific connexin 43 (Cx43) knockout mouse line (SCCx43KO) has provided a translational model. Expression of the gap junction protein Cx43 between adjacent SCs as well as between SCs and germ cells (GCs) is known to be essential for the initiation and maintenance of spermatogenesis in different species and men. Adult SCCx43KO males show altered spermatogenesis and are infertile. Thus, the present study aims to identify molecular mechanisms leading to testicular alterations in prepubertal SCCx43KO mice. Transcriptome analysis of 8-, 10- and 12-day-old mice was performed by next-generation sequencing (NGS). Additionally, candidate genes were examined by qRT-PCR and immunohistochemistry. NGS revealed many significantly differentially expressed genes in the SCCx43KO mice. For example, GC-specific genes were mostly downregulated and found to be involved in meiosis and spermatogonial differentiation (e.g., Dmrtb1, Sohlh1). In contrast, SC-specific genes implicated in SC maturation and proliferation were mostly upregulated (e.g., Amh, Fshr). In conclusion, Cx43 in SCs appears to be required for normal progression of the first wave of spermatogenesis, especially for the mitosis-meiosis switch, and also for the regulation of prepubertal SC maturation.

Curcumin-loaded super-paramagnetic iron oxide nanoparticle affects on apoptotic factors expression and histological changes in a prepubertal mouse model of polycystic ovary syndrome-induced by dehydroepiandrosterone - A molecular and stereological study

AimsThis study investigated the effects of curcumin-loaded super-paramagnetic iron oxide (Fe3O4) nanoparticles (NPs) (SPIONs) on histological parameters and apoptosis-inducing factors (AIFs) in an experimental mouse model of polycystic ovary syndrome (PCOS). Materials and methodsA total number of 40 female prepuberal BALB/c mice were randomly divided into four groups. Group 1 was selected as control and Group 2 was considered as a vehicle taking sesame oil, in the form of a curcumin carrier. Moreover, Group 3 was administered with dehydroepiandrosterone (DHEA) at 6 mg/100 g of the body weight and Group 4 received the DHEA plus the NPs of curcumin (5.4 mg/100 g) for twenty consecutive days. Finally, histology, stereology, and apoptosis of the ovary were evaluated. Key findingsThe results revealed that the NPs of curcumin had reduced ovarian volume (p < 0.05) and a total number of primary, secondary, antral, and primordial follicles in comparison with the PCOS and vehicle groups (p < 0.05). Furthermore, curcumin treatment following administration of the DHEA resulted in a significant decrease in BAX (p < 0.001) and levels of expression of Caspase3 (CASP3) protein, increased levels of B-cell lymphoma 2 (Bcl2) expression (p < 0.05), and moderated apoptosis in granulosa cells in comparison with the ones seen in the PCOS group. SignificanceOvarian injuries and DHEA-induced apoptosis were efficiently suppressed by curcumin, indicating the probable protective property of NPs of curcumin against PCOS.

Constant innervation despite pubertal growth of the mouse penis.

The sexual characteristics of the vertebrate body change under the control of sex hormones. In mammals, genitals undergo major changes in puberty. While such bodily changes have been well documented, the associated changes in the nervous system are poorly understood. To address this issue, we studied the growth and innervation of the mouse penis throughout puberty. To this end, we measured length and thickness of the mouse penis in prepubertal (3-4 week old) and adult (8-10 week old) mice and performed fiber counts of the dorsal penile nerve. We obtained such counts with confocal imaging of proximal sections of the mouse penis after paraffin embedding and antibody staining against Protein-Gene-Product-9.5 or Neurofilament-H in combination with antigen retrieval procedures. We find that the mouse penis grows roughly 1.4 times in both thickness and length. Fiber counts in the dorsal penile nerve were not different in prepubertal (1,620 ± 165 fibers per penis) and adult (1,572 ± 383 fibers per penis) mice, however. Antibody staining along with myelin staining by Luxol-Fast-Blue suggested about 57% of penile nerve fibers were myelinated. Quantification of the area of mouse somatosensory penis cortex allowed us to compare cortical magnification of the penile cortex and the whisker-barrel-cortex systems. This comparison suggested that 2 to 4 times less cortical area is devoted to a penile-nerve-fiber than to a whisker-nerve-fiber. The constant innervation of mouse penis through puberty suggests that the pubertal increase of cortical magnification of the penis is not simply a reflection of peripheral change.

Germinal stage vitrification is superior to MII stage vitrification in prepubertal mouse oocytes

This study investigated if in vitro maturation (IVM) before or after vitrification would be more successful for prepubertal oocytes. To mimic prepubertal conditions in an experimental setup, oocytes were collected from healthy 14, 21 and 28day old Swiss albino mice. The germinal vesicle (GV) stage oocytes and in vitro matured MII oocytes were subjected to vitrification-warming. Both structural (meiotic spindle morphology, mitochondrial integrity, cortical granules) and functional (sperm zona binding, fertilization) characteristics were assessed in oocytes after warming. This study demonstrated that IVM was more detrimental to prepubertal oocytes than to young adults. Further, vitrification of the IVM oocytes resulted in an increase in the number of abnormal meiotic spindles, a change in the cortical distribution pattern, a reduction in sperm zona binding and the fertilization rate. Importantly, oocyte integrity was better when prepubertal oocytes were vitrified before, rather than after, IVM. The above observations support GV stage vitrification for prepubertal oocytes requiring fertility preservation. Understanding the mechanisms behind the differing outcomes for oocytes from immature females will help in refining current protocol, thereby retaining the oocytes' maximum structural and functional integrity Further investigation is necessary to determine whether human prepubertal oocytes also behave in a similar way. It is to be noted here, with great emphasis, that a major limitation of this study is that the oocytes’ abilities were tested only until fertilisation, as a consequence of which the study cannot reveal the developmental potentials of the embryos beyond fertilisation.

Comparative gonadotoxicity of the chemotherapy drugs cisplatin and carboplatin on prepubertal mouse gonads.

The treatment of childhood cancer with chemotherapy drugs can result in infertility in adulthood. Newer generations of drugs are developed to replace parent drugs, with the potential benefits of less toxic side effects. For platinum alkylating-like drugs, in contrast to the parent compound cisplatin, the newer-generation drug carboplatin is reported to have reduced toxicity in some respects, despite being administered at 5–15 times higher than the cisplatin dose. Whether carboplatin is also less toxic than cisplatin to the reproductive system is unknown. Here we compare the gonadotoxic impact of cisplatin and carboplatin on female and male mouse prepubertal gonads. In vitro cultured CD1 mouse ovaries or testis fragments were exposed to either cisplatin or carboplatin for 24 h on Day 2 of culture and analysed by Day 6. A dose response for each drug was determined for the ovary (0.5, 1 & 5 μg/ml cisplatin and 1, 5 & 10 μg/ml carboplatin) and the testis (0.01, 0.05 & 0.1 μg/ml cisplatin and 0.1, 0.5 & 1 μg/ml carboplatin). For the ovary, unhealthy follicles were evident from 1 μg/ml cisplatin (73% unhealthy, P = 0.001) and 5 μg/ml carboplatin (84% unhealthy, P = 0.001), with a concomitant reduction in follicle number (P = 0.001). For the testis, the proliferating germ cell population was significantly reduced from 0.05 μg/ml cisplatin (73% reduction, P = 0.001) and 0.5 μg/ml carboplatin (75% reduction, P = 0.001), with no significant impact on the Sertoli cell population. Overall, results from this in vitro animal model study indicate that, at patient equivalent concentrations, carboplatin is no less gonadotoxic than cisplatin.

Dietary zinc supplement militates against ketamine-induced behaviours by age-dependent modulation of oxidative stress and acetylcholinesterase activity in mice.

The potential differential modulatory effects of zinc-supplemented diet on ketamine-induced changes in behaviours, brain oxidative stress, acetylcholinesterase activity, and zinc (ZN) levels were examined in prepubertal and aged mice. Aged and prepubertal mice were divided into 2 groups consisting of 80 aged and 80 prepubertal mice, each having 8 treatment groups of 10 animals each. The treatment groups are: vehicle control group (fed standard diet and given intraperitoneal {ip} normal saline), three groups fed ZN-supplemented diet (at 25, 50 and 100mg/kg of feed) and given ip normal saline, ketamine control group (fed standard diet and given ip ketamine), and finally another three groups fed ZN-supplemented diet (at 25, 50 and 100mg/kg of feed) and given ip ketamine. Intraperitoneal normal saline (at 2ml/kg/day) or ketamine (at 30mg/kg/day) were administered during the last 10days of study. On day 60, animals were exposed to the open-field, Y-maze, radial-arm maze, and elevated plus maze following which they were euthanised; blood and brain homogenate were used for assessment of biochemical parameters. Zinc supplementation was associated with an increase in food intake and body weight (in both age groups), a reduction in ketamine-induced increase in locomotion, rearing and grooming, and significantly higher working-memory scores (compared to ketamine control). Also, there was a decrease in anxiety-related behaviours, enhanced antioxidant status, reduced lipid peroxidation, and reduced acetylcholinesterase activity. In conclusion, dietary ZN supplementation was associated with variable degrees of prevention of ketamine-induced changes, depending on the age of animals.

Recombinant FSH glycoforms are bioactive in mouse preantral ovarian follicles.

Female reproductive aging is characterized by a rise in follicle-stimulating hormone (FSH) levels during peri-menopause. N-linked glycans are co-translationally attached to the Asn7 and Asn24 residues on the FSHβ subunit. Differences in the number of N-glycans on the FSHβ subunit result in distinct glycoforms: hypo-glycosylated (FSH21/18, glycans absent on either Asn24 or Asn7, respectively) or fully-glycosylated (FSH24, glycans present on both Asn7 and Asn24). The relative abundance of FSH glycoforms changes with advanced reproductive age, shifting from predominantly FSH21/18 in younger women to FSH24 in older women. Previous in vitro studies in granulosa cell lines and in vivo studies using Fshb-null mice showed these glycoforms elicit differential bioactivities. However, the direct effects of FSH glycoforms on the mouse ovarian follicle have not yet been determined. In this study, we isolated secondary follicles from pre-pubertal mice and treated them with 20- or 100 ng/mL purified recombinant FSH glycoforms for 1 h or 18-20 h. Analysis of phosphorylated PKA substrates showed that glycoforms were bioactive in follicles following 1-h treatment, although differential bioactivity was only observed with the 100 ng/mL dose. Treatment of follicles with 100 ng/mL of each glycoform also induced distinct expression patterns of FSH-responsive genes as assessed by qPCR, consistent with differential function. Our results, therefore, indicate that FSH glycoforms are bioactive in isolated murine follicles.

Evaluation of mitochondria in oocytes following \u03b3-irradiation

Standard cytotoxic cancer treatments, such as radiation, can damage and deplete the supply of oocytes stored within the ovary, which predisposes females to infertility and premature menopause later in life. The mechanisms by which radiation induces oocyte damage have not been completely elucidated. The objective of this study was to determine if γ-irradiation changes mitochondrial characteristics in oocytes, possibly contributing to a reduction in oocyte number and quality. Immature oocytes were collected from postnatal day (PN) 9–11 C57Bl6 mice 3, 6 and 24 hours after 0.1 Gy γ-irradiation to monitor acute mitochondrial changes. Oocytes were classified as small (>20 µm) or growing (40–60 µm). Mitochondrial membrane potential was lost in 20% and 44% of small oocytes (~20 µm) at 3 and 6 hours after γ-irradiation, respectively, consistent with the induction of apoptosis. However, mitochondrial mass, distribution and membrane potential in the surviving small oocytes were similar to the non-irradiated controls at both time points. At 24 hours after γ-irradiation, all mitochondrial parameters analysed within immature oocytes were similar to untreated controls. Mitochondrial parameters within growing oocytes were also similar to untreated controls. When mice were superovulated more than 3 weeks after γ-irradiation, there was a significant reduction in the number of mature oocytes harvested compared to controls (Control 18 ± 1 vs 0.1 Gy 4 ± 1, n = 6/16 mice, p < 0.05). There was a slight reduction in mitochondrial mass in mature oocytes after γ-irradiation, though mitochondrial localization, mtDNA copy number and ATP levels were similar between groups. In summary, this study shows that γ-irradiation of pre-pubertal mice is associated with loss of mitochondrial membrane potential in a significant proportion of small immature oocytes and a reduction in the number of mature oocytes harvested from adult mice. Furthermore, these results suggest that immature oocytes that survive γ-irradiation and develop through to ovulation contain mitochondria with normal characteristics. Whether the oocytes that survive radiation and eventually undergo meiosis can support fertility remains to be determined.

CYP26B1 declines postnatally in Sertoli cells independently of androgen action in the mouse testis.

Meiosis begins at puberty and relies on several factors, including androgens and retinoic acid in the mouse testis. CYP26B1 degrades retinoic acid in the testis during prenatal development preventing meiosis initiation. Given the concurrence of meiotic entry and completion of Sertoli cell maturation in response to androgens at puberty in the mouse, we proposed that CYP26B1 is downregulated by androgens in the Sertoli cell during this period. By immunohistochemistry, we showed that CYP26B1 declines in Sertoli cells after birth. However, luciferase reporter assays and quantitative reverse transcription-polymerase chain reaction performed in the prepubertal mouse Sertoli cell line SMAT1 revealed no changes in Cyp26b1 expression in response to androgen treatment. Furthermore, studies carried out using primary Sertoli cells of 10-day-old mice showed no changes in either Cyp26b1 or CYP26B1 expression in response to androgen treatment. In summary, the hereby reported decline in CYP26B1 expression in Sertoli cells towards pubertal onset does not appear to be caused by a direct inhibitory effect of androgens on Sertoli cells in the mouse.

Exposure to first line anti-tuberculosis drugs in prepubertal age reduces the quality and functional competence of spermatozoa and oocytes in Swiss albino mice

Prepubertal Swiss albino mice of both sex were administered with first-line anti-tuberculosis drugs (ATDs) viz; rifampicin, isoniazid, pyrazinamide, streptomycin and ethambutol intraperitoneally, for 4 weeks. Two weeks after the completion of treatment, male mice were sacrificed to collect caudal spermatozoa and female mice were superovulated with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) to collect metaphase II (MII) oocytes from oviduct. Administration of ATDs not only decreased the count, motility and, nuclear maturity and also, increased the head abnormalities, mitochondrial damage and DNA damage in epididymal spermatozoa. Reduction in number of ovulated oocytes, increased degeneration rate and altered distribution pattern of cytoplasmic organelles was observed in oocytes of female mice. Presence of ATDs in in vitro maturation (IVM) medium increased abnormalities in meiotic resulted in abnormal spindle organization (except ethambutol) without affecting nuclear maturation. In conclusion, the result of this study indicates that ATDs have considerable adverse effects on the functional competence of male and female gametes, however, with varied degree of toxicity.

Protective role of adiponectin against testicular impairment in high-fat diet/streptozotocin-induced type 2 diabetic mice

Type 2 diabetes (T2D) is the most common endocrine and metabolic disorder, leading to reproductive impairments and infertility in male. Our recent study showed crucial role of adiponectin in the regulation of testicular functions, and the circulating level of adiponectin declines in diabetes. The current study thus aimed to examine the efficacy of adiponectin in improving testicular dysfunction in high-fat diet/streptozotocin-induced T2D mice. T2D was induced in pre-pubertal mice fed with high-fat diet for ∼10 weeks followed by a single dose of streptozotocin. T2D mice showed presence of increased body mass, hyperglycemia, hyperinsulinemia, insulin resistance, increased oxidative stress, and declined serum testosterone compared to vehicle-treated control mice. The spermatogenic, steroidogenic, metabolic, and antioxidative parameters were evaluated in T2D mice treated with adiponectin for both two and four weeks. The exogenous administration of adiponectin to T2D mice showed enhanced serum testosterone and expression of testicular steroidogenic markers proteins, insulin receptor and GLUT8 proteins, increase in intra-testicular concentrations of glucose and lactate and activity of LDH and antioxidant enzymes compared to the levels in untreated T2D mice. This suggests that treatment of adiponectin effectively improves testicular functions by increasing expression of insulin receptor-mediated increased transport of energy substrate (glucose and lactate) and a marked reduction in oxidative stress are the possible mechanism by which adiponectin effectively improves testicular function in T2D mice.

Vitamin E but Not GSH Decreases Reactive Oxygen Species Accumulation and Enhances Sperm Production during In Vitro Maturation of Frozen-Thawed Prepubertal Mouse Testicular Tissue.

Freezing–thawing procedures and in vitro culture conditions are considered as a source of stress associated with increased reactive oxygen species (ROS) generation, leading to a damaged cell aerobic metabolism and consequently to oxidative stress. In the present study, we sought to investigate whether vitamin E (Vit E) or reduced glutathione (GSH) enhances sperm production by decreasing ROS accumulation during in vitro maturation of prepubertal mice testes. Testes of prepubertal mice were cryopreserved using a freezing medium supplemented or not supplemented with Vit E and were cultured after thawing. In presence of Rol alone in culture medium, frozen-thawed (F-T) testicular tissues exhibited a higher ROS accumulation than fresh tissue during in vitro culture. However, Vit E supplementation in freezing, thawing, and culture media significantly decreased cytoplasmic ROS accumulation in F-T testicular tissue during in vitro maturation when compared with F-T testicular tissue cultured in the presence of Rol alone, whereas GSH supplementation in culture medium significantly increased ROS accumulation associated with cytolysis and tissue disintegration. Vit E but not GSH promoted a better in vitro sperm production and was a suitable ROS scavenger and effective molecule to improve the yield of in vitro spermatogenesis from F-T prepubertal mice testes. The prevention of oxidative stress in the cytoplasmic compartment should be regarded as a potential strategy for improving testicular tissue viability and functionality during the freeze–thaw procedure and in vitro maturation.

Immunohistochemical localization and possible functions of nesfatin-1 in the testis of mice during pubertal development and sexual maturation.

The study was aimed to address the role of nesfatin-1 on the sexual maturation of testis during the pubertal transition. The immunostaining of testis suggested nesfatin-1 is expressed in Leydig cells with pubertal maturation. The pre-pubertal mice for in vivo study were randomly divided in three groups; (a) control-saline (b) treated with low (0.25nM) dose of nesfatin-1/gbw/day and (c) treated with high (1.25nM) dose nesfatin-1/gbw/day. Histological analysis showed that nesfatin-1 loaded mice showed facilitated maturation of testis. Western blot analysis on various protein expressions upon injection of nesfatin-1 into pre-pubertal mice suggested that expressions of proteins involving steroid hormone production, spermatogenic markers (PCNA, Bcl2, AR), glucose uptake-related proteins (GLUT8 and insulin receptor) and GnRH-R and GPR-54 proteins were facilitated. Both of lactose dehydrogenase activity and lactate levels were increased. The treatment with nesfatin-1 also reduced oxidative stress, which further facilitates testicular functions during puberty. The treatment of nesfatin-1 on cultured testis also supports in vivo findings as evident by the increased testosterone production and StAR protein expression as well as increased glucose and lactate production. In sum, our data report for the first time the accelerative role of nesfatin-1 on spermatogenesis and steroidogenesis of pre-pubertal male mice by directly acting on the testis coupled with the advancement of puberty.