Resveratrol and lycium barbarum polysaccharide improve Qinling giant panda (Ailuropoda melanoleuca Qinlingensis) sperm quality during cryopreservation

Effect of resveratrol on post-thaw motility, kinematics, structural parameters and antioxidant/oxidant status of Kamori buck spermatozoa

Resveratrol is a polyphenol compound showing strong antioxidant properties. It is believed that semen cryopreservation causes significant sperm losses which eventually affects sperm quality. Improving antioxidant status of semen may reduce this damage and enhance sperm fertilizing potential. This study investigated the resveratrol treated freeze-thawing sperm motion, kinetics, structural parameters and antioxidant/oxidant status of Kamori buck spermatozoa. Thirty-two ejaculates from 4 fertile Kamori bucks were processed in tris-citric-glyercol-egg yolk (TCG-EY) based with varying concentrations of resveratrol (0, 10, 20, 40 and 50 μM). Over 75 % sperm motility were pooled and frozen in liquid nitrogen. The results unveiled that adding resveratrol at 40 and 50 μM concentration significantly enhanced (P < 0.05) total motility (progressive motility, rapid velocity, and average path velocity, straight line velocity, curvilinear velocity, amplitude of lateral head displacement, beat cross frequency, straightness and linearity in contrast with control and other groups. Supplementing resveratrol at 40 and 50 μM concentration significantly improved (P < 0.05) functional plasma membrane integrity, acrosome integrity, whereas, all resveratrol groups had same significant (P < 0.05) effect on DNA integrity in response to control group. The 40 and 50 μM resveratrol significantly promoted (P < 0.05) superoxide dismutase (SOD), catalase (CAT), peroxidases (POD), and total antioxidant capacity (TAC) levels while significantly reducing (P < 0.05) the total oxidant status (TOS) and malondialdehyde (MDA) contents as compared to control and other groups, respectively. The principal component analysis (PCA) exhibited samples were present in different clusters except two groups which had partially overlapped. Using hierarchical clustering analysis, two clusters were constructed showing the relationship within the treated groups. The results of spearman correlation coefficient showed that yellow color showed highly positive correlation while turquoise color exhibited highly negative association between sperm variables. Overall, the results concluded that resveratrol at 50 μM performed slightly better results than 40 μM in terms of improving sperm quality parameters.

Mechanisms of oxidative stress-induced sperm dysfunction

Oxidative stress plays a pivotal role in male infertility by impairing sperm function through various molecular mechanisms. This review explores the impact of excessive reactive oxygen species (ROS) on spermatozoa, particularly focusing on lipid peroxidation, DNA fragmentation, and protein oxidation. Lipid peroxidation damages sperm membranes, reducing fluidity and motility. ROS-induced DNA fragmentation compromises genetic integrity, potentially leading to infertility and adverse offspring outcomes. Protein oxidation alters key structural proteins, impairing sperm motility and the ability to fertilize an egg. The primary sources of oxidative stress in sperm include leukocyte activity, mitochondrial dysfunction, and environmental factors such as smoking and pollution. Despite the presence of natural antioxidant defenses, spermatozoa are particularly vulnerable due to limited repair mechanisms. The review highlights the importance of early intervention through antioxidant therapies and lifestyle changes to mitigate the detrimental effects of oxidative stress on male fertility. Further research is essential to enhance therapeutic approaches and improve reproductive outcomes.

Polyphenols as a strategy for improving male reproductive system

Reproduction in males is one of the complicated processes that is mediated by many environmental factors, as well as by diet (e.g. supplements, nutritional value). The parameters of reproduction like sperm cells, hormones and testicular histology are highly prone to oxidative stress due to influence of factors on reproductive processes. Polyphenols are naturally present in feed of animals as shrubs, trees and agro-industrial by products. The exposures of these polyphenols through diet have strong antioxidants properties. However, the benefits of these substances on reproductive health are not always certain. The use of these polyphenols in the diet of animals and in the semen extender has been reported as remarkable benefits. These beneficial effects are manifested in the form of improvement of antioxidant potential via the reduction in the production of reactive oxygen species. Polyphenols are also used for cryopreservation of various species for the genetic improvement of various species. This review gathers all the findings related to dietary consumptions of polyphenols on reproductive performance of male of various species as well as use in semen extender in fresh and frozen semen.

Semen Cuscutae-Fructus Lycii attenuates tripterygium glycosides-induced spermatogenesis dysfunction by inhibiting oxidative stress-mediated ferroptosis via the Nrf2/HO-1 pathway

BACKGROUND

Semen Cuscutae and Fructus Lycii (SC-FL) is known for its potential therapeutic effects on spermatogenesis dysfunction. However, the underlying mechanisms of SC-FL in alleviating spermatogenesis dysfunction is still being elucidated.

PURPOSE

This study aimed to explore the effects of SC-FL on spermatogenesis dysfunction and investigate the involved mechanisms, specifically focusing on the modulation of oxidative stress and ferroptosis.

METHODS

A mouse model of spermatogenesis dysfunction was induced by tripterygium glycosides, followed by treatment with SC-FL. Assessment of testicular spermatogenic function in the mice was performed alongside lipidomics analysis to investigate the metabolic mechanisms of SC-FL. The effects on oxidative stress and ferroptosis-related markers were evaluated, the chemical constituents of SC-FL were identified using liquid chromatography-mass spectrometry, and network pharmacology analysis was carried out. Additionally, an in vitro model of spermatogenesis dysfunction was established using triptolide-induced GC-1 cells, which were treated with Lycium barbarum polysaccharides (LBP) and flavonoids from Semen Cuscutae (FSC) to explore their impact on cell damage, oxidative stress-mediated damage, and ferroptosis.

RESULTS

SC-FL improved the mouse model of spermatogenesis dysfunction by inhibiting oxidative stress-mediated ferroptosis. In vitro experiments demonstrated that LBP and FSC relieved GC-1 cell damage, with their mechanisms also associated with the inhibition of oxidative stress-mediated ferroptosis.

CONCLUSION

SC-FL alleviates spermatogenesis dysfunction in animal and cell models, potentially through the modulation of the Nrf2/HO-1 signaling pathway, which consequently inhibits oxidative stress-mediated ferroptosis in spermatogonial cells.

Ultrasound-assisted deep eutectic solvents extraction of polysaccharides from Loquat leaf: Process optimization and bioactivity study

Loquat leaves are the by-product of loquat fruit production. Polysaccharides are one of the main active ingredients in loquat leaves. In this study, polysaccharides were extracted from loquat leaves by ultrasonic-assisted deep eutectic solvents (DESs) extraction method. Further, the extracted crude loquat leaf polysaccharides (CLLP) were purified and separated via S-8 resin and DEAE-52 cellulose column chromatography, respectively. Additionally, the effects of polysaccharides on activity of sperm in boar semen preserved in medium at 17 °C, were evaluated preliminarily. DES, composed of choline chloride/ethylene glycol (1:6, molar ratio), was proved to be the suitable solvent for LLP extraction. The optimized extraction conditions were water content 44 %, liquid-solid ratio 1:29 (g/g), extraction temperature 61 °C and extraction time 98 min. Under these conditions, the LLP yield was 57.82 ± 1.50 mg/g. A homogeneous polysaccharide (LLP1-2, Mw: 2.17 × 104 Da) was isolated from CLLP. Its total sugar, uronic acid and protein contents were 76.31 ± 1.25 %, 14.19 ± 0.67 % and 3.28 ± 0.42 %, respectively. Further, 800 μg/mL LLP1-2 could effectively enhance the antioxidant activity of sperm. This study laid a foundation for DESs and column chromatography in the field of polysaccharide extraction and separation, proving that LLP can be used as a natural antioxidant for sperm preservation.

Effect of Five Different Antioxidants on the Effectiveness of Goat Semen Cryopreservation

The effective combination of semen cryopreservation and artificial insemination has a positive effect on the conservation of germplasm resources, production and breeding, etc. However, during the process of semen cryopreservation, the sperm cells are very susceptible to different degrees of physical, chemical, and oxidative stress damage. Oxidative damage is the most important factor that reduces semen quality, which is affected by factors such as dilution equilibrium, change of osmotic pressure, cold shock, and enzyme action during the freezing-thawing process, which results in the aggregation of a large amount of reactive oxygen species (ROS) in sperm cells and affects the quality of semen after thawing. Therefore, the method of adding antioxidants to semen cryoprotective diluent is usually used to improve the effect of semen cryopreservation. The aim of this experiment was to investigate the effects of adding five antioxidants (GLP, Mito Q, NAC, SLS, and SDS) to semen cryoprotection diluent on the cryopreservation effect of semen from Saanen dairy goats. The optimal preservation concentrations were screened by detecting sperm viability, plasma membrane integrity, antioxidant capacity, and acrosomal enzyme activities after thawing, and the experimental results were as follows: the optimal concentrations of GLP, Mito Q, NAC, SLS, and SDS added to semen cryopreservation diluent at different concentrations were 0.8 mg/mL, 150 nmol/L, 0.6 mg/mL, 0.15 mg/ mL, 0.6 mg/mL, and 0.15 mg/mL. The optimal concentrations of the five antioxidants were added to the diluent and analyzed after 1 week of cryopreservation, and it was found that sperm viability, plasma membrane integrity, and mitochondrial activity were significantly enhanced after thawing compared with the control group (P < 0.05), and their antioxidant capacity was significantly enhanced (P < 0.05). Therefore, the addition of the above five antioxidants to goat sperm cryodilution solution had a better enhancement of sperm cryopreservation. This study provides a useful reference for exploring the improvement of goat semen cryoprotection effect.

Natural mating ability is associated with gut microbiota composition and function in captive male giant pandas

The issue of poor sexual performance of some male giant pandas seriously impairs the growth and the genetic diversity of the captive population, yet there is still no clear understanding of the cause of the loss of this ability and its underlying mechanism. In this study, we analyzed the gut microbiota and its function in 72 fecal samples obtained from 20 captive male giant pandas, with an equal allocation between individuals capable and incapable of natural mating. Additionally, we investigated fecal hormone levels and behavioral differences between the two groups. A correlation analysis was then conducted among these factors to explore the influencing factors of their natural mating ability. The results showed significant differences in the composition of gut microbiota between the two groups of male pandas. The capable group had significantly higher abundance of Clostridium sensu stricto 1 (p adjusted = .0021, GLMM), which was positively correlated with fatty acid degradation and two-component system functions (Spearman, p adjusted < .05). Additionally, the capable group showed higher gene abundance in gut microbiota function including purine and pyrimidine metabolism and galactose metabolism, as well as pathways related to biological processes such as ribosome and homologous recombination (DEseq2, p adjusted < .05). We found no significant differences in fecal cortisol and testosterone levels between the two groups, and no difference was found in their behavior either. Our study provides a theoretical and practical basis for further studying the behavioral degradation mechanisms of giant pandas and other endangered mammal species.

Evaluation of Kappa-carrageenan supplementation in extender for post-thaw Kajli ram sperm quality

Cryopreservation is one of the reliable techniques for long-term storage of sperm. The success of this technique depends on the choice of cryoprotectant; therefore, a plethora of literature has reported the effects of different cryoprotective agents so far. Kappa-carrageenan (κ-carrageenan) is a hydrocolloid polysaccharide extracted from red marine seaweed. Its unique property makes it a promising option as a non-colligative cryoprotectant. The current study aims to evaluate the cryoprotective effect of k-carrageenan along with glycerol on ram sperm quality both after equilibration and freezing. Nine Kajli rams were utilized in this experiment for semen collection through an artificial vagina maintained at 42°C. Qualified samples were diluted in tris egg yolk glycerol (TEYG) extender containing different concentrations of k-carrageenan as 0 mg/mL (control), 0.2, 0.5, 0.8 and 1 mg/mL. Post-thaw assessment was done at 37°C after 24 h of storage, which showed a significant improvement (p < .05) in sperm viability, motility, membrane and acrosome integrity in an extender containing k-carrageenan at a concentration of 0.5 mg/mL compared to control. It is concluded from the current study that the combination of glycerol and 0.5 mg/mL concentration of k-carrageenan improved the sperm post-thaw quality.

Resveratrol Improves the Frozen-Thawed Ram Sperm Quality

Cryopreservation generates a substantial quantity of ROS in semen, leading to a decline in sperm quality and fertilization capacity. The objective of this study was to investigate the effects of resveratrol and its optimal concentration on ram sperm quality after cryopreservation. Ram semen was diluted with a freezing medium containing different concentrations of resveratrol (0, 25, 50, 75, and 100 μM). After thawing, various sperm parameters such as total motility, progressive motility, acrosome integrity, plasma membrane integrity, mitochondrial membrane potential, glutathione (GSH) content, glutathione synthase (GPx) activity, superoxide dismutase (SOD) activity, catalase (CAT) activity, lipid peroxidation (LPO) content, malondialdehyde (MDA) content, ROS level, SIRT1 level, DNA oxidative damage, and AMPK phosphorylation level were assessed. In addition, post-thaw sperm apoptosis was evaluated. Comparatively, the addition of resveratrol up to 75 μM significantly improved the sperm motility and sperm parameters of cryopreserved ram sperm. Specifically, 50 μM resveratrol demonstrated a notable enhancement in acrosome and plasma membrane integrity, antioxidant capacity, mitochondrial membrane potential, adenosine triphosphate (ATP) content, SIRT1 level, and AMPK phosphorylation levels compared to the control group (p < 0.05). It also significantly (p < 0.05) reduced the oxidative damage to sperm DNA. However, detrimental effects of resveratrol were observed at a concentration of 100 μM resveratrol. In conclusion, the addition of 50 μM resveratrol to the cryopreservation solution is optimal for enhancing the quality of cryopreserved ram sperm.

Qiangjing tablets ameliorate asthenozoospermia via mitochondrial ubiquitination and mitophagy mediated by LKB1/AMPK/ULK1 signaling

CONTEXT

Therapeutic effects of Qiangjing tablets (QJT) on sperm vitality and asthenozoospermia (AZS) have been confirmed. However, the mechanism of action remains unclear.

OBJECTIVE

This study investigates the effects of QJT on AZS and the underlying mechanism of action.

MATERIALS AND METHODS

Sixty Sprague-Dawley rats were randomly divided into six groups: Control, ORN (ornidazole; 200 mg/kg), ORN + QJT-low (0.17 g/mL), ORN + QJT-middle (0.33 g/mL), ORN + QJT-high (0.67 g/mL), and ORN + QJT + Radicicol (0.67 g/mL QJT and 20 mg/kg radicicol) groups. Pathological evaluation and analysis of mitophagy were conducted by H&E staining and transmission electron microscopy, respectively. Reactive oxygen species were detected by flow cytometry. Protein expression was determined by Western blotting.

RESULTS

QJT significantly improved ORN-treated sperm motility and kinematic parameters, as well as the pathological symptoms of testicular and epididymal tissues. In particular, QJT mitigated impaired mitochondrial morphology, and increased the PHB, Beclin-1, LC3-II protein, and ROS levels (p < 0.05), and reduced the protein expression levels of LC3-I and p62 (p < 0.05). Mechanistically, QJT antagonized the downregulation of SCF and Parkin protein levels (p < 0.05). Furthermore, QJT significantly increased the protein expressions levels of LKB1, AMPKα, p-AMPKα, ULK1 and p-ULK1 (p < 0.05). The ameliorative effect of QJT on pathological manifestations, mitochondrial morphology, and the expressions of mitophagy and mitochondrial ubiquitination-related proteins was counteracted by radicicol.

DISCUSSION AND CONCLUSIONS

QJT improved AZS via mitochondrial ubiquitination and mitophagy mediated by the LKB1/AMPK/ULK1 signaling pathway. Our study provides a theoretical basis for the treatment of AZS and male infertility.

Comparison between Hematology and Serum Biochemistry of Qinling and Sichuan Giant Panda (Ailuropoda melanoleuca qinlingensis and sichuanensis)

Giant pandas are the flagship species in world conservation, and include two subspecies, Ailuropoda melanoleuca qinlingensis (A. m. qinlingensis) and Ailuropoda melanoleuca sichuanensis (A. m. sichuanensis). Hematology and serum biochemistry studies are crucial to protecting giant pandas. Even though research on hematology and serum biochemistry are well-established in A. m. sichuanensis, research in A. m. qinlingensis is scarce. The study aimed to (1) establish a baseline for hemogram and reference intervals (RIs) for hematological and serum biochemical parameters in A. m. qinlingensis, (2) assess the possible variations in these parameters of A. m. qinlingensis based on age, gender, and storage condition of blood samples, and (3) compare the parameters to those of A. m. sichuanensis. Blood samples (n = 42) were collected from healthy A. m. qinlingensis (n = 21) housed in Shaanxi (Louguantai) Rare Wildlife Rescue and Breeding Research Center, and hematological (n = 25) and serum biochemical parameters (n = 18) were analyzed in March and December of 2019. The results showed no significant abnormality in the blood smears of all individuals in this study, except for a few serrated red blood cells, platelet aggregations, and occasionally giant platelets. Between sub-adult and adult A. m. qinlingensis, there were significant differences in five hematological and one serum biochemical parameter (p < 0.05), whereas six serum biochemical parameters were present when α = 0.1 (p < 0.1). Gender influenced % NEU, % LYM, % EOS, LYM, EOS, GGT, and CHOL of A. m. qinlingensis. The majority of the hematological and serum biochemical parameters of A. m. qinlingensis were different from those of A. m. sichuanensis regarding age and gender. The anticoagulant whole blood samples of A. m. qinlingensis stored at 2-8 °C for 24 h and the serum samples stored at -18 °C for 48 h had little influence on the values of hematological and serum biochemical parameters. In conclusion, this study provided a baseline of hemogram and established RIs for hematological and serum biochemical parameters of A. m. qinlingensis. RIs of A. m. sichuanensis reported before were not completely fit for A. m. qinlingensis, and age, gender, or the storage condition of blood samples influenced some of the parameters of A. m. qinlingensis. To the authors' knowledge, this is the first report of a hemogram baseline and RIs for hematological and serum biochemical parameters of A. m. qinlingensis.