Ameliorating high-fat diet-induced sperm and testicular oxidative damage by micronutrient-based antioxidant intervention in rats

Hydroxycitric acid and capsaicin combination alleviates obesity-induced testicular apoptosis, oxidative stress and inflammation

Recent research in rodents suggests that oxidative stress, inflammation, and apoptosis in the testes caused by high-fat diets (HFD) are a cause of male infertility. To investigate the therapeutic efficacy of the combination of hydroxycitric acid and capsaicin (HCC) against male reproductive disorders, we developed an HFD-induced obese rat model. Rats received HFD supplementation for 21 weeks, which induced obesity. From week 16, HCC (100 mg/kg body weight) was administered to investigate its potential to treat testicular toxicity. According to the results of the current study, treatment of obese rats with HCC improved their sperm quality, increased the production of testosterone, follicle-stimulating hormone, and luteinizing hormone and significantly increased the activities of steroidogenic enzymes and corresponding mRNA levels. In addition, HCC decreased lipid peroxidation and nitric oxide levels in both spermatozoa and testes while increasing the expression of mRNA for the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase in the testes, which in turn reduced oxidative stress in the testes. Moreover, after HCC treatment, testicular tissues showed a remarkable decrease in mRNA levels responsible for inflammation (TNF-α, IL-6, NF-κB) and apoptosis (Bax and Bcl-2). Our results suggest that HCC may alleviate obesity-induced male reproductive dysfunction by attenuating oxidative stress, inflammation, and apoptosis in the testes of HFD-induced obese male rats.

Reliable Detection of Excessive Sperm Ros Production in Subfertile Patients: How Many Men with Oxidative Stress?

Sperm oxidative stress has been extensively associated to male infertility. However, tests to detect this parameter have not been yet introduced in clinical practice and no definitive data are present on the extent of oxidative stress in male infertility. In this study, we used a novel and reliable flow cytometric method to reveal sperm ROS production in subfertile patients (n = 131) and in healthy donors (n = 31). Oxidative stress was higher in subfertile patients (14.22 [10.21-22.08]%) than in healthy donors (9.75 [8.00-14.90]% (p < 0.01)), but no correlation was found with age, semen quality or sDF. We also failed to detect an increase in sperm ROS production with semen viscosity or leukocytospermia, but a sharp impact of semen bacteria was evident (with bacteria: 31.61 [14.08-46.78]% vs. without bacteria: 14.20 [10.12-22.00]%, p < 0.01). Finally, after establishing a threshold as the 95th percentile in healthy donors, we found that 29% of subfertile patients exceeded this threshold. The percentage decreased to 25.56% when we excluded subjects with bacteriospermia and increased to 60.87% when only these patients were considered. In conclusion, 29% of subfertile patients showed an excessive sperm ROS production. Surprisingly, this parameter appears to be independent from routine semen analysis and even sDF determination, promising to provide additional information on male infertility.

Sperm chromatin: Evaluation, epigenetic signatures and relevance for embryo development and assisted reproductive technology outcomes

Sperm chromatin is distinct from somatic cell chromatin, as a result of extensive remodeling during the final stages of spermatogenesis. In this process, the majority of histones is replaced with protamines. The chromatin is consequently highly condensed and inert, which facilitates protection of the DNA. The sperm epigenomic landscape is shaped by histone retention, histone and protamine modification, DNA methylation, and RNAs. In recent years, sperm chromatin integrity and its epigenetic marks have been increasingly studied, and the constitution of sperm chromatin is steadily being uncovered. This growing body of research prompts assessment of the frequently overlooked involvement of sperm in fertility and embryonic development. Moreover, numerous endogenous and exogenous factors are known to affect sperm chromatin, which may in turn impact the reproductive success. Concerns have been raised about the effects of assisted reproductive technology (ART) on the sperm epigenome, embryonic development and offspring health. This review examines the structure and epigenetic signatures of sperm chromatin in the context of fertility and early embryonic development. Additionally, sperm chromatin evaluation and causes of aberrant integrity are outlined. Building on the knowledge discussed in the current review, future research should aim to elucidate the intricate relationship between all aspects of sperm chromatin and embryo development. This could lead to the uncovering of new targets for treating infertility, as well as the acquisition of much needed insights into the possible reciprocal association between ART and sperm chromatin integrity.

Revisiting the Injury Mechanism of Goat Sperm Caused by the Cryopreservation Process from a Perspective of Sperm Metabolite Profiles

Semen cryopreservation results in the differential remodeling of the molecules presented in sperm, and these alterations related to reductions in sperm quality and its physiological function have not been fully understood. Given this, this study aimed to investigate the cryoinjury mechanism of goat sperm by analyzing changes of the metabolic characteristics in sperm during the cryopreservation process. The ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) technique was performed to explore metabolite profiles of fresh sperm (C group), equilibrated sperm (E group), and frozen-thawed sperm (F group). In total, 2570 metabolites in positive mode and 2306 metabolites in negative mode were identified, respectively. After comparative analyses among these three groups, 374 differentially abundant metabolites (DAMs) in C vs. E, 291 DAMs in C vs. F, and 189 DAMs in E vs. F were obtained in the positive mode; concurrently, 530 DAMs in C vs. E, 405 DAMs in C vs. F, and 193 DAMs in E vs. F were obtained in the negative mode, respectively. The DAMs were significantly enriched in various metabolic pathways, including 31 pathways in C vs. E, 25 pathways in C vs. F, and 28 pathways in E vs. F, respectively. Among them, 65 DAMs and 25 significantly enriched pathways across the three comparisons were discovered, which may be tightly associated with sperm characteristics and function. Particularly, the functional terms such as TCA cycle, biosynthesis of unsaturated fatty acids, sphingolipid metabolism, glycine, serine and threonine metabolism, alpha-linolenic acid metabolism, and pyruvate metabolism, as well as associated pivotal metabolites like ceramide, betaine, choline, fumaric acid, L-malic acid and L-lactic acid, were focused on. In conclusion, our research characterizes the composition of metabolites in goat sperm and their alterations induced by the cryopreservation process, offering a critical foundation for further exploring the molecular mechanisms of metabolism influencing the quality and freezing tolerance of goat sperm. Additionally, the impacts of equilibration at low temperature on sperm quality may need more attentions as compared to the freezing and thawing process.

Effect of Advanced Glycation end Products (AGEs) on Sperm Parameters and Function in C57Bl/6 Mice

This study investigated the deleterious impact of advanced glycation end products (AGEs), commonly present in metabolic disorders like diabetes, obesity, and infertility-related conditions, on sperm structure and function using a mouse model where AGE generation was heightened through dietary intervention. Five-week-old C57BL/6 mice were divided into two groups, one on a regular diet (control) and the other on an AGE-rich diet. After 13 weeks, various parameters were examined, including fasting blood glucose, body weight, food consumption, sperm parameters and function, testicular superoxide dismutase levels, malondialdehyde content, total antioxidant capacity, Johnson score, AGE receptor (RAGE) content, and carboxymethyl lysine (CML) content. The results showed that mice in the AGE group exhibited increased body weight and elevated fasting blood glucose levels. Furthermore, the AGE group displayed adverse effects on sperm, including reduced sperm counts, motility, increased morphological abnormalities, residual histone, protamine deficiency, sperm DNA fragmentation, reduced testicular antioxidant capacity, and higher levels of RAGE and CML proteins. These findings underscore the negative impact of AGEs on male reproductive health, particularly within the context of metabolic disorders, emphasizing the crucial role of the AGE/RAGE axis in male infertility, especially in the context of Western dietary patterns.

Preconceptional paternal caloric restriction of high-fat diet-induced obesity in Wistar rats dysregulates the metabolism of their offspring via AMPK/SIRT1 pathway

BACKGROUND

Obesity is a metabolic syndrome where allelic and environmental variations together determine the susceptibility of an individual to the disease. Caloric restriction (CR) is a nutritional dietary strategy recognized to be beneficial as a weight loss regime in obese individuals. Preconceptional parental CR is proven to have detrimental effects on the health and development of their offspring. As yet studies on maternal CR effect on their offspring are well established but paternal CR studies are not progressing. In current study, the impact of different paternal CR regimes in diet-induced obese male Wistar rats (WNIN), on their offspring concerning metabolic syndrome are addressed.

METHODS

High-fat diet-induced obese male Wistar rats were subjected to caloric restriction of 50% (HFCR-I) and 40% (HFCR-II) and then they were mated with normal females. The male parent's reproductive function was assessed by sperm parameters and their DNMT's mRNA expression levels were also examined. The offspring's metabolic function was assessed by physiological, biochemical and molecular parameters.

RESULTS

The HFCR-I male parents have shown reduced body weights, compromised male fertility and reduced DNA methylation activity. Further, the HFCR-I offspring showed attenuation of the AMPK/SIRT1 pathway, which is associated with the progression of proinflammatory status and oxidative stress. In line, the HFCR-I offspring also developed altered glucose and lipid homeostasis by exhibiting impaired glucose tolerance & insulin sensitivity, dyslipidemia and steatosis. However, these effects were largely mitigated in HFCR-II offspring. Regarding the obesogenic effects, female offspring exhibited greater susceptibility than male offspring, suggesting that females are more prone to the influences of the paternal diet.

CONCLUSION

The findings highlight that HFCR-I resulted in paternal undernutrition, impacting the health of offspring, whereas HFCR-II largely restored the effects of a high-fat diet on their offspring. As a result, moderate caloric restriction has emerged as an effective weight loss strategy with minimal implications on future generations. This underscores the shared responsibility of fathers in contributing to sperm-specific epigenetic imprints that influence the health of adult offspring.

Oral administration of proniosomal glibenclamide formulation protects testicular tissue from hyperglycemia fluctuations and ROS via Nrf2/HO-1 pathway

Type 2 diabetes causes high blood sugar due to insulin malfunction and is linked to male infertility. Using proniosomes can enhance the effectiveness of Glibenclamide, a medication that stimulates insulin secretion. In our study, male rats with diabetes were treated with GLB with or without proniosomal for 14 days. Proniosomal formulations maintained glucose levels prevented weight loss and showed normal testicular tissue. GLB-proniosomal reduces ROS caused by T2DM through Nrf2, HO-1 pathway and increases CAT, SOD, and GSH production in response to insulin and glucose uptake. The reference and proniosomal treatments showed CAT and SOD significant enzymatic elevation compared to the positive and negative control. CAT significantly correlated with Gpx4 expression with P = 0.0169 and r = 0.98; similarly, the enzymatic activity of SOD also showed a positive correlation between the average glucose levels (r = 0.99 and P = 0.0037). Intestinally, GSH analysis revealed that only proniosomal-GLB samples are significantly elevated from the positive control, with a P value of 0.0210. The data showed proniosomal-GLB was more effective than pure GLB, confirmed by higher Nrf2 (2.050 folds), HO-1 (2.148 folds), and GPx4 (1.9 folds) transcript levels relative to the control with less sample diversity compared to the reference samples, indicating proniosomal stabilized GLB in the blood. Administering GLB and proniosomes formulation has effectively restored testicular function and sperm production in diabetic rats by regulating ROS levels and upregulating anti-ROS in response to glucose uptake. These findings may lead to better treatments for diabetic patients who have infertility issues.

Maternal high-fat diet during pregnancy and lactation affects factors that regulate cell proliferation and apoptosis in the testis of adult progeny

Context A maternal high-fat diet is thought to pose a risk to spermatogenesis in the progeny. Aims We tested whether a maternal high-fat diet would affect Sertoli cell expression of transcription factors (insulin-like growth factor I (IGF-I); glial-cell line-derived neurotrophic factor (GDNF); Ets variant 5 (ETV5)) and cell proliferation and apoptotic proteins, in the testis of adult offspring. Methods Pregnant rats were fed ad libitum with a standard diet (Control) or a high-fat diet (HFat) throughout pregnancy and lactation. After weaning, male pups were fed the standard diet until postnatal day 160. Males were monitored daily from postnatal day 34 to determine onset of puberty. On postnatal day 160, their testes were processed for morphometry and immunohistochemistry. Key results The HFat diet increased seminiferous-tubule diameter (P P P P P P P P Conclusions A maternal high-fat diet alters the balance between spermatogonia proliferation and spermatid apoptosis. Implications A maternal high-fat diet seems to 'program' adult male fertility.

Betaine postpones hyperglycemia-related senescence in ovarian and testicular cells: Involvement of RAGE and β-galactosidase

The structural and functional disorders of the testis and ovary are one of the main complications of hyperglycemia. Betaine is a trimethyl glycine with antioxidant, antidiabetic, and anti-inflammatory potential. The aim of this study is to investigate the potential of betaine on the expression of aging and oxidative stress markers in ovarian and testicular cells under hyperglycemic conditions. Testicular and ovarian cells were subjected to four different conditions, including normal glucose and hyperglycemia, with or without betaine (5 mM). The cells with hyperglycemia saw an increase in malondialdehyde (MDA), methylglyoxal (MGO), expression of a receptor for AGE, and aging-related genes (β-GAL), and a decrease in the activity of antioxidant enzymes including catalase, glutathione peroxidase, and superoxide dismutase. The treatment with betaine, in contrast, decreased the amount of MGO and MDA, and also downregulated aging-related signaling. Although hyperglycemia induces senescence in testicular and ovarian cells, the use of betaine may have a protective effect against the cell senescence, which may be useful in the management of infertility.

Epigallocatechin-gallate attenuates rapamycin exacerbated high fat diet-induced autophagy, hormonal dysregulation, testicular and brain oxidative stress, and neurochemical changes in rats

This study investigated whether epigallocatechin-gallate (EGCG) could counteract the detrimental effects of high-fat diet (HFD)-induced obesity in rats exposed to rapamycin-induced reproductive and neuronal changes. Six rats per treatment group (n = 6) were utilized, in which groups 1 and 2 had dimethylsulfoxide (DMSO) (0.1%) and EGCG (80 mg/kg) respectively. Group 3 received HFD + 0.1% DMSO daily for 56 days. Group 4 received HFD + rapamycin (1 mg/kg) orally for 56 days. Rats in group 5 received HFD for 56 days and EGCG (80 mg/kg, p.o.) from days 29-56. Group 6 received the combination of HFD + rapamycin (56 days) with EGCG (80 mg/kg) from days 29-56. Cognitive loss was assessed using Y-maze-test (YMT). Afterwards, serum sex hormones, insulin-glucose balance, serotonin concentration, acetylcholinesterase activity, sperm features, antioxidants, and the markers of oxido-nitrergic, autophagy and apoptotic mediators were assessed. EGCG reversed rapamycin exacerbated HFD-induced alterations in spermatogenesis, insulin-glucose balance, reproductive hormones, oxido-nitrergic stress, and altered serotonin, acetylcholinesterase levels, and autophagic and apoptotic activities in rats' testes and brains respectively. EGCG significantly attenuated HFD-induced cognitive loss. The study showed that EGCG attenuated rapamycin-mediated HFD-induced spermatogenesis deficiency and cognitive impairment via normalization of reproductive hormones, testicular and brain oxidative stress, apoptotic, autophagic activities, with serotonin and cholinergic levels in rats.

A short-term high-fat diet alters rat testicular activity and blood-testis barrier integrity through the SIRT1/NRF2/MAPKs signaling pathways

Background

Overweight/obesity are metabolic disorder resulting from behavioral, environmental, and heritable causes. WHO estimates that 50% of adults and 30% of children and adolescents are overweight or obese, and, in parallel, an ongoing decline in sperm quality and male fertility has been described. Numerous studies demonstrated the intimate association between overweight/obesity and reproductive dysfunction due to a highly intricate network of causes not yet completely understood. This study expands the knowledge on the impact of a short-term high-fat diet (st-HFD) on rat testicular activity, specifically on steroidogenesis and spermatogenesis, focusing on the involved molecular mechanisms related to mitochondrial dynamics, blood-testis barrier (BTB) integrity, and SIRT1/NRF2/MAPKs pathways.

Methods

Ten adult Male Wistar rats were divided into two groups of five and treated with a standard diet or an HFD for five weeks. At the end of the treatment, rats were anesthetized and sacrificed by decapitation. Blood was collected for serum sex hormone assay; one testis was stored at -80ÅãC for western blot analysis, and the other, was fixed for histological and immunofluorescence analysis.

Results

Five weeks of HFD results in reduced steroidogenesis, increased apoptosis of spermatogenic cells, and altered spermatogenesis, as highlighted by reduced protein levels ofmeiotic and post-meiotic markers. Further, we evidenced the compromission of the BTB integrity, as revealed by the downregulation of structural proteins (N-Cadherin, ZO-1, occludin, connexin 43, and VANGL2) other than the phosphorylation of regulative kinases (Src and FAK). At the molecular level, the impairment of mitochondrial dynamics (fission, fusion, andbiogenesis), and the dysregulation of the SIRT1/NRF2/MAPKs signaling pathways, were evidenced. Interestingly, no change was observed in the levels of pro-inflammatory markers (TNFα, NF-kB, and IL-6).

Conclusions

The combined data led us to confirm that overweight is a less severe state than obesity. Furthermore, understanding the molecular mechanisms behind the association between metabolic disorders and male fertility could improve the possibility of identifying novel targets to prevent and treat fertility disorders related to overweight/obesity.

Effects of folic acid and folic acid plus zinc supplements on the sperm characteristics and pregnancy outcomes of infertile men: A systematic review and meta-analysis

Background

Folic acid and zinc supplements have been used to treat male infertility, but their efficacy is still debated.

Objective

To systematically evaluate the effects of folic acid and folic acid plus zinc supplements on sperm characteristics and pregnancy outcomes of infertile men.

Methods

An online systematic search was performed using PubMed, Cochrane Library, and EMBASE databases from inception to August 1, 2022. The goal was to identify randomized controlled trials (RCTs) that used folic acid or folic acid plus zinc to improve sperm characteristics of infertile men. Data were extracted by two investigators who independently screened the literature and assessed for quality according to the criteria. The meta-analysis was performed using RevMan 5.4 software.

Results

A total of 8 RCT studies involving 2168 patients were included. The results showed that compared with the controls, folic acid significantly increased sperm motility (MD, 3.63; 95% CI, -1.22 to 6.05; P = 0.003), but did not affect the sperm concentration (MD, 2.53; 95% CI, -1.68 to 6.73; P = 0.24) and sperm morphology (MD, -0.02; 95% CI, -0.29 to 0.24; P = 0.86) in infertile men. Folic acid plus zinc did not affect sperm concentration (MD, 1.87; 95% CI, -1.39 to 5.13; P = 0.26), motility (MD, 1.67; 95% CI, -1.29 to 4.63; P = 0.27), and morphology (MD, -0.05; 95% CI, -0.27 to 0.18; P = 0.69) in infertile men. Secondary results showed that compared with a placebo, folic acid alone had a higher rate of pregnancy in transferred embryos (35.6% vs. 20.4%, P = 0.082), but the difference was not significant. Folic acid plus zinc did not affect pregnancy outcomes.

Conclusions

Based on the meta-analysis, no significant improvements in sperm characteristics with folic acid plus zinc supplements were seen. However, folic acid alone has demonstrated the potential to improve sperm motility and in vitro fertilization-intracytoplasmic sperm injection (IVF-ICSI) outcomes. This indicates that folic acid supplements alone may be a viable treatment option for male infertility.

Vitamin B3 Provides Neuroprotection via Antioxidative Stress in a Rat Model of Anterior Ischemic Optic Neuropathy

Supplementing with vitamin B3 has been reported to protect against retinal ganglion cell (RGC) damage events and exhibit multiple neuroprotective properties in a mouse model of optic nerve injury. In this study, a rat model of anterior ischemic optic neuropathy was used to assess the neuroprotective benefits of vitamin B3 (rAION). Vitamin B3 (500 mg/kg/day) or phosphate-buffered saline (PBS) was administered to the rAION-induced rats every day for 28 days. The vitamin B3-treated group had significantly higher first positive and second negative peak (P1-N2) amplitudes of flash visual-evoked potentials and RGC densities than the PBS-treated group (p < 0.05). A terminal deoxynucleotidyl transferase dUTP nick end labeling assay conducted on vitamin B3-treated rats revealed a significant reduction in apoptotic cells (p < 0.05). Superoxide dismutase and thiobarbituric acid reactive substance activity showed that vitamin B3 treatment decreased reactive oxygen species (p < 0.05). Therefore, vitamin B3 supplementation preserves vision in rAION-induced rats by reducing oxidative stress, neuroinflammation, and mitochondrial apoptosis.

The combination of ginger and zinc supplement could improve lead-induced reproductive dysfunction by inhibiting apoptosis mediated by oxidative damage and inflammation

Due to the growing industry and industrialization of many urban communities, one of the dangers that threaten human life is long-term exposure to heavy metals such as lead. Lead contamination can have a detrimental effect on fertility. On the other hand, the combination of ginger and zinc supplements can be a powerful sexual enhancer. Despite extensive studies on the effect of ginger and zinc on reproduction, the effects of the combination of ginger and zinc supplement on lead-induced reproductive dysfunction are not fully understood. Sixty-four adult male rats were allocated into control, lead acetate (10 mg/kg), ginger (250 mg/kg), ginger-lead group, zinc (120 mg/kg) group, zinc-lead group, ginger-zinc group and ginger-zinc-lead group. The drugs were administrated by gavage for 4 weeks. The concentration of LH, FSH, testosterone, TNF-α, IL-1β, antioxidant enzyme activity, MDA, spermatogenesis, and sperm parameters were measured. The expression of NF-kB, Nrf2, Bcl2, BAX, and Cas-3 was evaluated. The histopathological assessment was also detected. Lead significantly could induce inflammation, apoptosis, and oxidative damage in testis tissue, and decrease hormonal levels, spermatogenesis, and sperm parameters compared to the control group (p < 0.05). While in reverse manner ginger, zinc, and their combination significantly improved all of them compared to the lead group (p < 0.05). These results were also supported by histological findings. It can be concluded that ginger, zinc, and their combination could prevent lead-induced reproductive dysfunction by inhibiting apoptosis mediated by oxidative damage and inflammation and improve reproductive performance.