Metabolomic profiling of Dezhou donkey sperm associated with freezability

Ram sperm cryopreservation disrupts metabolism of unsaturated fatty acids

In ram sperm, metabolites are important components of the plasma membrane, energy metabolism cycle, and precursors for other membrane lipids, and they may have important roles in maintaining plasma membrane integrity, energy metabolism, and regulation of cryotolerance. In this study, the ejaculates from 6 Dorper rams were pooled and sperm were systematically investigated by metabolomics at various steps of cryopreservation (37 °C, fresh [F]; from 37 to 4 °C, cooling [C]; and from 4 to -196 to 37 °C, frozen-thawed [FT]) to identify differential metabolites (DM). There were 310 metabolites identified, of which 86 were considered DMs. Regarding the DMs, there were 23 (0 up and 23 down), 25 (12 up and 13 down), and 38 (7 up and 31 down) identified during cooling (C vs F), freezing (FT vs C), and cryopreservation (FT vs F), respectively. Furthermore, some key polyunsaturated fatty acids (FAs), particularly, linoleic acid (LA), docosahexaenoic acid (DHA), and arachidonic acid (AA) were down-regulated during cooling and cryopreservation. Significant DMs were enriched in several metabolic pathways including biosynthesis of unsaturated FAs, LA metabolism, mammalian target of rapamycin (mTOR), forkhead box transcription factors (FoxO), adenosine monophosphate-activated protein kinase (AMPK), phosphatidylinositol 3-kinase/protein kinase B (PI3K-Akt) signaling pathways, regulation of lipolysis in adipocytes, and FA biosynthesis. This was apparently the first report to compare metabolomics profiles of ram sperm during cryopreservation and provided new knowledge to improve this process.

Metabolomic analysis of seminal plasma to identify goat semen freezability markers

Factors affecting sperm freezability in goat seminal plasma were investigated. Based on the total motility of thawed sperm, goats were divided into a high-freezability (HF) group with >60% total motility (n = 8) and a low-freezability (LF) group with <45% total motility (n = 8). Sperm and seminal plasma from the HF and LF groups were separated, HF seminal plasma was mixed with LF spermatozoa, LF seminal plasma was mixed with HF sperm, and the products were subjected to a freeze-thaw procedure. Semen from individual goats exhibited differences in freezability. HF semen had higher sperm motility parameters and plasma membrane and acrosome integrity after thawing; this difference could be related to the composition of seminal plasma. Seminal plasma from the HF and LF groups was evaluated using metabolomic analysis, and multivariate statistical analysis revealed a clear separation of metabolic patterns in the seminal plasma of goats with different freezability classifications. Forty-one differential metabolites were identified using the following screening conditions: variable importance in the projection > 1 and 0.05 < P-value < 0.1. Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed significant enrichment of central carbon metabolism in cancer, protein digestion and absorption, aminoacyl-tRNA, and other pathways and significant differences in the abundance of seven differential metabolites, including L-glutamine, L-aspartate, L-arginine, phenylpyruvate, benzoic acid, ketoisocaproic acid, and choline between seminal plasma from the HF and LF groups (P-value < 0.05). These significantly differentially-expressed metabolites may be potential biomarkers for sperm freezability. L-glutamine, L-aspartate, and L-arginine may directly affect sperm freezability. Benzoic acid, ketoisocaproic acid, and choline may regulate sperm freezability by participating in anabolic processes involving phenylalanine, leucine, and phosphatidylcholine in sperm.

Cryopreservation of Human Spermatozoa: Functional, Molecular and Clinical Aspects

Cryopreservation is an expanding strategy to allow not only fertility preservation for individuals who need such procedures because of gonadotoxic treatments, active duty in dangerous occupations or social reasons and gamete donation for couples where conception is denied, but also for animal breeding and preservation of endangered animal species. Despite the improvement in semen cryopreservation techniques and the worldwide expansion of semen banks, damage to spermatozoa and the consequent impairment of its functions still remain unsolved problems, conditioning the choice of the technique in assisted reproduction procedures. Although many studies have attempted to find solutions to limit sperm damage following cryopreservation and identify possible markers of damage susceptibility, active research in this field is still required in order to optimize the process. Here, we review the available evidence regarding structural, molecular and functional damage occurring in cryopreserved human spermatozoa and the possible strategies to prevent it and optimize the procedures. Finally, we review the results on assisted reproduction technique (ARTs) outcomes following the use of cryopreserved spermatozoa.

Study on comparative analysis of differential metabolites in Guanzhong dairy goat semen before and after freezing

In order to explore the differential metabolites between fresh and frozen-thawed semen of Guanzhong dairy goats, semen samples were collected by artificial vagina method, and divided into fresh and frozen-thawed semen groups, with six replicates in each group. Liquid Chromatography-mass spectrometry (LC-MS) technology was used to detect semen metabolites in both groups. The metabolites were analyzed and identified by the combination of multidimensional statistical analysis, namely principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), orthogonal partial least squares discriminant analysis (OPLS-DA) and univariate statistical analysis, Differential metabolites were identified according to One-step Solution for Identification of Small Molecules in Metabolomics Studies (OSI/SMMS) combined with Human Metabolome Database (HMDB), Lipidmaps and Metlin and the metabolic pathways of different metabolites were enriched and analyzed by Kyoto Encyclopedia of Genes and Genomes (KEGG) database. The results showed that a total of 53 differential metabolites were detected in fresh and frozen-thawed semen groups, of which 10 metabolites were significantly up-regulated (P < 0.05) and 43 were significantly down-regulated (P < 0.05). Most of the metabolites belonged to lipids and lipid-like molecules, organic acids and their derivatives, organic oxygen compounds, etc. According to the functional enrichment analysis of the top twenty differential metabolites in the KEGG database, significant changes occurred in linoleic acid metabolism pathway out of total eleven pathways observed. These differential metabolites can be used as metabolic markers of sperm cryo-injury in dairy goats.

Allochthonous arbuscular mycorrhizal fungi promote Salix viminalis L.-mediated phytoremediation of polycyclic aromatic hydrocarbons characterized by increasing the release of organic acids and enzymes in soils

Polycyclic aromatic hydrocarbons (PAHs) are well known persistent organic pollutants that have carcinogenic, teratogenic, and mutagenic effects on humans and animals. Arbuscular mycorrhizal fungi (AMF) that can infest plant hosts and form symbioses may help plants to enhance potential rhizosphere effects, thus contributing to the rhizodegradation of PAH-contaminated soils. The present study aimed to assess the effectiveness of AMF on enhancing Salix viminalis-mediated phytoremediation of PAH-polluted soil and clarify the plant enzymatic and organic acid mechanisms induced by AMF. Natural attenuation (NA), phytoremediation (P, Salix viminalis), S. viminalis-AMF combined remediation using willow inoculated with Funneliformis mosseae (PM), Laroideoglomus etunicatum (PE), and Rhizophagus intraradices (PI) were used as strategies for the remediation of PAH-polluted soils. The results showed that AMF inoculation contributed to the dissipation of the high-molecular-weight PAH benzo (α) pyrene that had concentrations in PM, PE, and PI treatments of 40.1 %, 24.49 %, and 36.28 % of the level in the NA treatment, and 62.32 %, 38.05 %, and 56.38 % of the level in the P treatment after 90 days. The mycorrhizal treatment also improved the removal efficiency of phenanthrene and pyrene, as their concentrations were sharply decreased after 30 days compared to the NA and P treatments. The research further clarified the changes in rhizosphere substances induced by AMF. Organic acids including arachidonic acid, octadecanedioic acid, α-linolenic acid, 10,12,14-octadecarachidonic acid and 5-methoxysalicylic acid that can act as co-metabolic substrates for certain microbial species to metabolize PAHs were significantly increased in AMF-inoculated treatments. AMF inoculation also elevated the levels of polyphenol oxidase, laccase, and dehydrogenase, that played crucial roles in PAHs biodegradation. These findings provide an effective strategy for using AMF-assisted S. viminalis to remediate PAH-polluted soils, and the results have confirmed the key roles of organic acids and soil enzymes in plant-AMF combined remediation of PAHs.

Regulation of semen quality by fatty acids in diets, extender, and semen

Fatty acids (FAs) are classified into different types according to the degree of hydrocarbon chain saturation, including saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), omega-3 polyunsaturated fatty acids (omega-3 PUFAs) and omega-6 polyunsaturated fatty acids (omega-6 PUFAs), which play an important role in maintaining semen quality. This review focuses on the regulation of FAs in semen, diet and extender on semen quality, and expounds its effects on sperm motility, plasma membrane integrity, DNA integrity, hormone content, and antioxidant capacity. It can be concluded that there are species differences in the FAs profile and requirements in sperm, and their ability to regulate semen quality is also affected by the addition methods or dosages. Future research directions should focus on analyzing the FAs profiles of different species or different periods of the same species and exploring suitable addition methods, doses and mechanism of regulating semen quality.

Evaluation of lipidomic change in goat sperm after cryopreservation

The current study aimed to detect the relationship between the spermatozoa cryotolerance and the post-thawed sperm lipidome. Ejaculates from 20 goats, and performed a uniform frozen-thawed procedure in this study. According to the total motility of thawed sperm of goats, semen samples were classified into HF group (High Freezers, n = 8) with >60% total motility and LF group (Low Freezers, n = 8) with < 45% total motility. The lipidomic analysis based on UHPLC-MS/MS was utilized to investigate the relationship between sperm cryotolerance and their lipid metabolites expression. The results showed that the cryotolerance of sperm from different individual goats were in great variation. The total motility of post-thawed sperm in HF group (60.93 ± 2.43%) is significantly higher than that in LF group (34.04 ± 3.41%, P < 0.01). And the post-thawed sperm in HF group exhibited significantly higher plasma membrane (59.06 ± 2.34%) and acrosome integrity (62.93 ± 1.15%) than that in LF group (34.06 ± 4.85%, 44.92 ± 2.19% respectively, P < 0.01). The total of 29 lipid subclasses and 1,133 lipid molecules in the post-thawed goat sperm were identified by lipidomics analysis. The lipid content of thawed sperm in HF group was higher than that in LF group, the lipid profile in HF group was significantly separated from LF group, which indicated that the difference in lipid composition and lipid metabolism mode of sperm between the two groups was existed, especially the expression of phosphatidylcholine and triglyceride molecules. In conclusion, the cryotolerance of sperm from different individual goats were in great variation. Sperm with high cryotolerance may be able to uptake more lipids during cryopreservation. The increase in phosphatidylcholine and triglyceride content of thawed. Sperm may relate to more active lipid anabolic processes.

In-depth investigation of the hypoglycemic mechanism of Morchella importuna polysaccharide via metabonomics combined with 16S rRNA sequencing

Increasing evidence indicates that type 2 diabetes mellitus (T2DM) is closely related to intestinal bacteria disorders and abnormal hepatic metabolism. Morchella importuna polysaccharide (MIP) shows excellent hypoglycemic activity in vitro. However, the hypoglycemic effect and mechanism of MIP in vivo have yet to be investigated. In this study, the blood glucose, blood lipid and insulin resistance of diabetic mice after MIP intervention were measured to evaluate its hypoglycemic effect. Then, the microbiome and metabolomics were combined to explore the hypoglycemic mechanism of MIP. Results indicated that high dose MIP (400 mg/kg) had significant hypoglycemic effect. Furthermore, MIP could reverse diabetes-induced intestinal disorder by increasing the abundance of Akkermansia, Blautia, Dubosiella, and Lachnospiraceae, as well as decreasing the abundance of Helicobacteraceae. Besides, the hepatic metabolites and complex network systems formed by multiple metabolic pathways were regulated after MIP treatment. Notably, a new biomarker of diabetes (N-P-coumaroyl spermidine) was discovered in this study. Moreover, the significant association between intestinal bacteria and hepatic metabolites was determined by correlations analysis, which in turn confirmed MIP alleviated T2DM via the gut-liver axis. Therefore, these findings elucidated in-depth hypoglycemic mechanisms of MIP and provided a new biomarker for the prevention of diabetes.

Comparative Lipidomic and Metabolomic Analyses Reveal the Mystery of Lacquer Oil from Toxicodendron vernicifluum for the Treatment of “Yuezi” Disease in Nujiang, China: From Anti-Inflammation and Anti-Postpartum Depression Perspective

Background: In southwest China, especially in Nujiang, lacquer oil from the drupes of Toxicodendron vernicifluum (Stokes) F. A. Barkley, including black lacquer oil (BLO) and white lacquer oil (WLO), is one of the most important edible oils for the local people. Through the field investigation, the locals believe that lacquer oil has benefits for parturient women and for the treatment of “Yuezi” disease. However, studies on bioactivities and the chemical compositions of lacquer oil are limited.

Purpose: This study was designed to reveal the mystery of lacquer oil for the treatment of “Yuezi” disease by testing its anti-inflammatory and anti-postpartum depressant activities and related bioactive compounds.

Methods: The anti-inflammatory effects of lacquer oil were examined by establishing a lipopolysaccharide (LPS)-induced RAW264.7 cell inflammation model and detecting the level of pro-inflammatory factors such as NO, IL-6 and TNF-α. The antidepressant effects of lacquer oil were studied by building a mouse model of postpartum depression (PPD), and the animal behavior changes of PPD model mice were assessed by open field test (OFT), forced swimming test (FST) and tail suspension test (TST). The chemical profiles of BLO and WLO were detected by lipidomic and the untargeted metabolomic research methods based on UPLC-MS/MS.

Results: The results showed that BLO and WLO exerted anti-inflammatory effects by reducing the release of pro-inflammatory factors and BLO had better anti-inflammatory effects than WLO. While only BLO had anti-postpartum depressant activities, as evidenced by the significantly reduced the immobility time of the BLO-treated PPD mice in TST and FST compared to the PPD model mice. The comparative lipidomic analysis revealed that BLO contained high levels of Diacylglycerols (DAG) and Diacylglyceryl trimethylhomoserines (DGTS) but low level of ceramides (Cer), sphingomyelines (SM), phosphatidylcholines (PC) and phosphatidylethanolamines (PE) compared with WLO. Metabolomics analysis showed that there were 57 chemical markers between BLO and WLO, of which 17 potential biomarkers have been declared to possess anti-inflammatory and/or antidepressant activities.

Conclusion: The findings of this study furnish a scientific support for the traditional uses of lacquer oil for the treatment of “Yuezi” disease from anti-inflammation and anti-postpartum depression perspective.

The Effect of Semen Cryopreservation Process on Metabolomic Profiles of Turkey Sperm as Assessed by NMR Analysis

Semen cryopreservation represents the main tool for preservation of biodiversity; however, in avian species, the freezing−thawing process results in a sharp reduction in sperm quality and consequently fertility. Thus, to gain a first insight into the molecular basis of the cryopreservation of turkey sperm, the NMR-assessed metabolite profiles of fresh and frozen−thawed samples were herein investigated and compared with sperm qualitative parameters. Cryopreservation decreased the sperm viability, mobility, and osmotic tolerance of frozen−thawed samples. This decrease in sperm quality was associated with the variation in the levels of some metabolites in both aqueous and lipid sperm extracts, as investigated by NMR analysis. Higher amounts of the amino acids Ala, Ile, Leu, Phe, Tyr, and Val were found in fresh than in frozen−thawed sperm; on the contrary, Gly content increased after cryopreservation. A positive correlation (p < 0.01) between the amino acid levels and all qualitative parameters was found, except in the case of Gly, the levels of which were negatively correlated (p < 0.01) with sperm quality. Other water-soluble compounds, namely formate, lactate, AMP, creatine, and carnitine, turned out to be present at higher concentrations in fresh sperm, whereas cryopreserved samples showed increased levels of citrate and acetyl-carnitine. Frozen−thawed sperm also showed decreases in cholesterol and polyunsaturated fatty acids, whereas saturated fatty acids were found to be higher in cryopreserved than in fresh sperm. Interestingly, lactate, carnitine (p < 0.01), AMP, creatine, cholesterol, and phosphatidylcholine (p < 0.05) levels were positively correlated with all sperm quality parameters, whereas citrate (p < 0.01), fumarate, acetyl-carnitine, and saturated fatty acids (p < 0.05) showed negative correlations. A detailed discussion aimed at explaining these correlations in the sperm cell context is provided, returning a clearer scenario of metabolic changes occurring in turkey sperm cryopreservation.