Histomorphological testicular changes and decrease in the sperm count in pubertal rats induced by a high-sugar diet

Unseen Threats: The Long-term Impact of PET-Microplastics on Development of Male Reproductive Over a Lifetime

The physical abrasion of plastics from simple everyday entered the food chain, with associated risks recently emphasized. Although many studies have reported the adverse effects of microplastics (MPs) on human, the reproductive implications of continuous exposure to physically abraded polyethylene terephthalate (PET)-MPs remain unexplored. Ingestion of physically abraded PET-MPs (size range: 50-100 µm) in mice from 5 to 34 weeks of age at an annual intake relevant dose of MPs (5 mg week-1) significantly impaired male reproductive function. Reductions in seminiferous tubule diameter and epithelial height are observed (p < 0.0001), with 32.2% decrease in Leydig cells and 24.3% reduction in testosterone levels (p < 0.05). The epididymis shows marked deterioration in all regions, with total sperm concentration significantly reduce from 17.0 × 10⁶ to 5.3 × 10⁶ (p < 0.01) and decrease motility. Transcriptome analysis demonstrates downregulation of genes related with gonadotropin-releasing hormone secretion, testosterone biosynthesis, and Meiosin gene, which is for crucial spermatogenesis. Continuous ingestion of physically abraded PET-MPs from plastic bottles adversely affected testicular and epididymal functions, leading to hormonal imbalances and abnormal sperm production. These findings raise concerns about the impact of commonly used plastics on male reproductive development, highlighting potential risks for future generations.

Exploring the ameliorative potential of rutin against High-Sucrose Diet-induced oxidative stress and reproductive toxicity in Drosophila melanogaster

Sucrose is a vital ingredient in numerous food items consumed regularly. However, exposure to excessive sucrose for a prolonged period can promote health issues. The reproductive system has a delicate physiology that can be targeted by various chemical stressors, including sucrose. Hence, the present in vivo study aims to unveil the impacts of High-Sucrose Diet (HSD) on the reproductive fitness of Drosophila melanogaster. In addition, the present work has also assessed the protective potential of a bioactive compound, rutin, against it. Here, first instar larvae were exposed to HSD (30 %) alone and in combination with rutin (100-300 µM) till their adult stage. HSD disturbed sex comb morphology in adult males, while fecundity and hatchability of eggs in females. Moreover, HSD triggered gonadal ROS production, oxidative stress, and modulated endogenous antioxidants such as SOD, catalase, and glutathione in both sexes. Nuclear fragmentation and tissue injuries, along with protein and lipid oxidation, were also apparent. Elevated levels of cytosolic Iron suggested an active Fenton reaction in adults. Further, HSD modulated the activities of reproductive and metabolic mediators, including vitellogenin, malate dehydrogenase, glucose-6-phosphate dehydrogenase, and angiotensin-converting enzymes that are critical to maintain the overall reproductive fitness. Interestingly, co-treatment with rutin, mainly at 200 µM, mitigated these adverse effects and restored reproductive fitness. The protective potential of rutin might be attributed to its ability to normalize redox homeostasis, reduce oxidative stress, and optimize critical enzymes involved in reproductive physiology. These findings suggest that rutin has potential therapeutic implications for counteracting the reproductive hazards induced by HSD.

African walnut (Plukenetia conophora) oil promotes glucose uptake while improving energy metabolism and steroidogenesis and maintaining surface architecture in rat testes

Background

African walnut (Plukenetia conophora) oil (AWO) has been reported for its nutritional and medicinal properties and has been employed for the management of metabolic diseases including hyperglycemia-mediated ailments.

Objective

In the present study, AWO was investigated for its ability to stimulate glucose uptake and its effect on energy metabolism, steroidogenesis, and tissue morphology in isolated testes of Wistar rats.

Methods

Isolated testes were incubated with AWO (30-240 μg/mL) in the presence of 11.1 mMol glucose at 37°C for 2 h. Control consisted of testes incubated with glucose only, while normal control consisted of testes not incubated with AWO and/or glucose. The standard antidiabetic drug was metformin.

Results and conclusion

Incubation with AWO led to significant increase in glucose uptake, hexokinase, glyoxalase 1, glutathione reductase, glutathione peroxidase, 3β-hydroxysteroid dehydrogenase, 17β-hydroxysteroid dehydrogenase activities, GLUT4, glutathione, and ATP levels while concomitantly suppressing glucose-6-phosphatase, fructose-1,6-biphosphatase, glycogen phosphorylase, aldose reductase, polyol dehydrogenase, E-NTPDase, and ATPase activities. Furthermore, incubation with AWO led to improved testicular morphology while elevating testicular levels of magnesium, sulfur, potassium, calcium, and iron. Fatty acid profiling with GC-MS revealed linoleic acid and linolenic acid as the predominant essential fatty acids in AWO. Molecular docking analysis revealed potent molecular interactions of linoleic acid and linolenic acid with GLUT4. These results suggest the ability of AWO to improve testicular glucose metabolism and steroidogenesis and can be explored in the management of male infertility.

Secretome of human amniotic membrane stem cells promote recovery and testicular functions through modulating SIRT1/NRF2/TNF-α pathway in mice testicular torsion: An experimental study

Background

Testicular ischemia/reperfusion injury, a significant result of testicular torsion, can lead to the risk of male infertility.

Objective

The current study aimed to evaluate the effect of human amniotic membrane-derived mesenchymal stem cells (hAMSCs) secretome on testicular torsion/detorsion (T/D) in mice.

Materials and Methods

All the experiments were performed in the Anatomy Department of Tehran University of Medical Sciences, Tehran, Iran, during the period of March 2023 to December 2023. 40 male NMRI mice (5-7 wk, 25-30 gr) were randomized into: 1) the sham group: mice received sham operations with no other interventions, 2) T/D group, 3) negative control group; torsion detorsion + intratesticular injection of Dulbecco's Modified Eagle Medium/Nutrient Mixture F-12, and 4) the T/D group + hAMSCs secreted factors. Serum testosterone levels, hematoxylin and eosin staining, and sperm quality parameters were used to evaluate the therapeutic effects of hAMSCs secreted factors on the testicular structure and function. Tissue oxidative stress was measured by determining malondialdehyde, superoxide dismutase, catalase, and glutathione peroxidase-1. Nuclear factor erythroid 2-related factor 2, Kelch-like ECH-associated protein 1, NAD-dependent deacetylase sirtuin-1, tumor necrosis factor-alpha and tumor protein P53 mRNA expressions were assessed in testis via real-time polymerase chain reaction.

Results

The results showed that hAMSCs secreted factors alleviated testicular T/D injury by attenuating oxidative stress, inflammatory response, and apoptosis via modulating the sirtuin-1/ nuclear factor erythroid 2-related factor 2/tumor necrosis factor-alpha signaling pathway.

Conclusion

hAMSCs secreted factors increased antioxidative, anti-inflammatory, and antiapoptotic properties which consequently increased testosterone levels, spermatogenesis, and sperm quality parameters.

Bridging the Gap: Animal Models in Next-Generation Reproductive Technologies for Male Fertility Preservation

This review aims to explore advanced reproductive technologies for male fertility preservation, underscoring the essential role that animal models have played in shaping these techniques through historical contexts and into modern applications. Rising infertility concerns have become more prevalent in human populations recently. The surge in male fertility issues has prompted advanced reproductive technologies, with animal models playing a pivotal role in their evolution. Historically, animal models have aided our understanding in the field, from early reproductive basic research to developing techniques like artificial insemination, multiple ovulation, and in vitro fertilization. The contemporary landscape of male fertility preservation encompasses techniques such as sperm cryopreservation, testicular sperm extraction, and intracytoplasmic sperm injection, among others. The relevance of animal models will undoubtedly bridge the gap between traditional methods and revolutionary next-generation reproductive techniques, fortifying our collective efforts in enhancing male fertility preservation strategies. While we possess extensive knowledge about spermatogenesis and its regulation, largely thanks to insights from animal models that paved the way for human infertility treatments, a pressing need remains to further understand specific infertility issues unique to humans. The primary aim of this review is to provide a comprehensive analysis of how animal models have influenced the development and refinement of advanced reproductive technologies for male fertility preservation, and to assess their future potential in bridging the gap between current practices and cutting-edge fertility techniques, particularly in addressing unique human male factor infertility.

Dietary intervention in adult rats exposed to a high-sugar diet early in life permanently impairs sperm quality

Childhood obesity predicts the presence of adult obesity. Obesity is associated with poor sperm quality. We hypothesized that exposure to a high-sugar diet (HSD) in early life would cause permanent histomorphology damage to the testes, resulting in reduced sperm quality in adult life. Wistar rats (aged 21days) were divided into four groups (n=6). In the first experiment, the rats received tap water (control) and a 30% sucrose diet for two months (S30). In the second experiment, the control and 30% sucrose diets were fed for two months, followed by replacement with tap water for two months (IS30). Eating and drinking were monitored. Animals were then euthanized, visceral and gonadal fat tissue and testes were collected, and epididymal spermatozoa were excised. Testicular samples were used for morphological description by H&E staining and for quantifying triacylglycerol content, caspase activity, and oxidative stress. Serum testosterone concentration was evaluated. Spermatozoa were used to assess sperm quality. Our results show that sperm quality was impaired by consuming HSD and could not be restored by dietary intervention. HSD feeding induced hyperplasia of visceral adipose tissue, increased testicular weight, and serum testosterone levels. The dietary intervention increased visceral adipose tissue, serum, and testicular triacylglycerol levels and normalized serum testosterone levels. Overall, the HSD diet caused permanent changes in seminiferous tubule cross-sectional area, caspase activity, oxidative stress, and sperm quality. Therefore, a high-sugar diet in early life causes permanent damage to sperm quality in adulthood.

High-sucrose diet-fed male rats show affectations in pubococcygeus reflex activation and myofiber content

In males, the function of the pubococcygeus muscle (Pcm) shows a high androgen dependency. High sucrose intake increases testosterone levels in pubertal male rats. We aimed to analyze the Pcm reflex activity and fiber type in response to a 30 % sucrose diet. Wistar male rats were assigned into two groups: control and sugar. The Pcm electromyographic activity was recorded during the mechanical stimulation of the scrotal skin and penis. We also determined the relative levels of Glut4 expression, glycogen content, myofiber cross-sectional area (CSA), and the content of glycolytic and oxidative with NADH-TR or fast, intermediate, and slow fibers with alkaline (pH 9.4) ATPase histochemistry. The sugar group showed a short Pcm reflex activity, a higher Glut4 expression, and glycogen content; the CSA fibers showed a significant difference in the percentage of fibers with the different transversal areas. The number of nuclei was positively correlated with the CSA of the Pcm fibers. There was also a decrease in oxidative fibers but an increase in glycolytic fibers, while the content of fast muscle fibers increased to the detriment of intermediate and slow fibers. Thus, a high-sugar diet reduced Pcm reflex activity, fiber type, and dysregulation of skeletal muscle energy metabolism.

Sexual selection drives the coevolution of male and female reproductive traits in Peromyscus mice

When females mate with multiple partners within a single reproductive cycle, sperm from rival males may compete for fertilization of a limited number of ova, and females may bias the fertilization of their ova by particular sperm. Over evolutionary timescales, these two forms of selection shape both male and female reproductive physiology when females mate multiply, yet in monogamous systems, post-copulatory sexual selection is weak or absent. Here, we examine how divergent mating strategies within a genus of closely related mice, Peromyscus, have shaped the evolution of reproductive traits. We show that in promiscuous species, males exhibit traits associated with increased sperm production and sperm swimming performance, and females exhibit traits that are predicted to limit sperm access to their ova including increased oviduct length and a larger cumulus cell mass surrounding the ova, compared to monogamous species. Importantly, we found that across species, oviduct length and cumulus cell density are significantly correlated with sperm velocity, but not sperm count or relative testes size, suggesting that these female traits may have coevolved with increased sperm quality rather than quantity. Taken together, our results highlight how male and female traits evolve in concert and respond to changes in the level of post-copulatory sexual selection.

Maternal and Offspring Sugar Consumption Increases Perigonadal Adipose Tissue Hypertrophy and Negatively Affects the Testis Histological Organization in Adult Rats

Sugar intake has been associated with the development of male reproductive pathologies because of the increase and dysfunction in different adipose tissue depots. The establishment of these dysfunctions in the early stages of development is unknown. We evaluated the effect of maternal (pregnancy and lactation) and male offspring (from weaning to adulthood) consumption of 5% sucrose on perigonadal adipose tissue (PAT) and testis in adulthood. Moreover, two rat groups were compared, both including pregnant and lactating females: Control (C—drinking tap water) and sugar (S—consuming 5% sucrose solution). From weaning to adulthood with male offspring, four subgroups were formed: Control Mother → Control and Sugar offspring (CC, CS) and Sugar Mother → Control and Sugar offspring (SC, SS). At 120 postnatal days, the testes and PAT were collected and morphologically described. Furthermore, we quantified the number and cross-sectional area of perigonadal adipocytes and their distribution. We found that the males from SC and SS groups showed high PAT weight (p < 0.005), a high number (p < 0.05), and a relative frequency of large adipocytes (p < 0.05), establishing these results during gestational and lactation stages, and enhancing in adulthood since postnatal diet and its interaction. More macrophages, mast cells, and Leydig cells were observed in the interstitial space of the testis for the CS, SC, and SS groups, concluding that consumption of a high-carbohydrate maternal diet, program hypertrophy processes in adult PAT, developing and enhancing with sugar consumption during postnatal life. Furthermore, they are associated with inflammatory processes within the interstitial space of the testis.