l-carnitine reduces the adverse effects of ROS and up-regulates the expression of implantation related genes in in vitro developed mouse embryos

Potential utility of l-carnitine for preventing liver tumors derived from metabolic dysfunction-associated steatohepatitis

BACKGROUND

Recent reports have unveiled the potential utility of l-carnitine to alleviate metabolic dysfunction-associated steatohepatitis (MASH) by enhancing mitochondrial metabolic function. However, its efficacy at preventing the development of HCC has not been assessed fully.

METHODS

l-carnitine (2 g/d) was administered to 11 patients with MASH for 10 weeks, and blood liver function tests were performed. Five patients received a serial liver biopsy, and liver histology and hepatic gene expression were evaluated using this tissue. An atherogenic plus high-fat diet MASH mouse model received long-term l-carnitine administration, and liver histology and liver tumor development were evaluated.

RESULTS

Ten-week l-carnitine administration significantly improved serum alanine transaminase and aspartate transaminase levels along with a histological improvement in the NAFLD activity score, while steatosis and fibrosis were not improved. Gene expression profiling revealed a significant improvement in the inflammation and profibrotic gene signature as well as the recovery of lipid metabolism. Long-term l-carnitine administration to atherogenic plus high-fat diet MASH mice substantially improved liver histology (inflammation, steatosis, and fibrosis) and significantly reduced the incidence of liver tumors. l-carnitine directly reduced the expression of the MASH-associated and stress-induced transcriptional factor early growth response 1. Early growth response 1 activated the promoter activity of neural precursor cell expressed, developmentally downregulated protein 9 (NEDD9), an oncogenic protein. Thus, l-carnitine reduced the activation of the NEDD9, focal adhesion kinase 1, and AKT oncogenic signaling pathway.

CONCLUSIONS

Short-term l-carnitine administration ameliorated MASH through its anti-inflammatory effects. Long-term l-carnitine administration potentially improved the steatosis and fibrosis of MASH and may eventually reduce the risk of HCC.

The effect of L-carnitine on oocyte mitochondrial health and biomarkers on cyclophosphamide chemotherapy drug in mice

Improving oocyte competence during chemotherapy is widely known as a contributing factor to increasing the probability of fertility. Additionally, the role of cumulus cells in oocyte quality is of utmost importance. Therefore, this study was designed to simultaneously probe into the relative gene expression of oocytes and cumulus cells as biomarkers of oocyte quality with cyclophosphamide and L-carnitine treatment. A total of 60 adult NMRI mice were divided into four groups: control, L-carnitine (LC), cyclophosphamide (CP), and cyclophosphamide+L-carnitine (CP+LC). The relative mRNA expression levels of oocyte quality genes including growth differentiation factor 9 (Gdf9), hyaluronan synthase 2 (Has2), and mitochondrial sirtuin 3 (Sirt3) in oocytes, and genes involved in bilateral communication between cumulus cells and between the oocyte and its neighboring cumulus cells including connexin 37 (Cx37) and connexin 43 (Cx43) were detected by Real-time-PCR. DCFH-DA staining analyzed the level of intracellular ROS in oocytes. Under the influence of L-carnitine, Gdf9, Has2, Cx43, and Cx37 were significantly up-regulated (p ≤ 0.05). However, cyclophosphamide considerably reduced the expression of all these genes (p ≤ 0.05). The expression of the Sirt3 gene in the CP group increased significantly compared to the other groups (p ≤ 0.05). Analysis of fluorescent images revealed that the level of intracellular ROS in the cyclophosphamide group was significantly increased compared to the other groups (p ≤ 0.05), while it plummeted in the L-carnitine group (p ≤ 0.05). L-carnitine as an antioxidant can reduce the destructive effects of cyclophosphamide and enhance bilateral communications between oocytes and cumulus cells, and it may ultimately lead to an increase in the fertility rate.

Advanced maternal age leads to changes within the insulin/IGF system and lipid metabolism in the reproductive tract and preimplantation embryo: insights from the rabbit model

Reproductive potential in women declines with age. The impact of ageing on embryo-maternal interactions is still unclear. Rabbits were used as a reproductive model to investigate maternal age-related alterations in reproductive organs and embryos on Day 6 of pregnancy. Blood, ovaries, endometrium, and blastocysts from young (16-20 weeks) and advanced maternal age phase (>108 weeks, old) rabbits were analysed at the mRNA and protein levels to investigate the insulin-like growth factor (IGF) system, lipid metabolism, and stress defence system. Older rabbits had lower numbers of embryos at Day 6 of pregnancy. Plasma insulin and IGF levels were reduced, which was accompanied by paracrine regulation of IGFs and their receptors in ovaries and endometrium. Embryos adapted to hormonal changes as indicated by reduced embryonic IGF1 and 2 levels. Aged reproductive organs increased energy generation from the degradation of fatty acids, leading to higher oxidative stress. Stress markers, including catalase, superoxide dismutase 2, and receptor for advanced glycation end products were elevated in ovaries and endometrium from aged rabbits. Embryonic fatty acid uptake and β-oxidation were increased in both embryonic compartments (embryoblast and trophoblast) in old rabbits, associated with minor changes in the oxidative and glycative stress defence systems. In summary, the insulin/IGF system, lipid metabolism, and stress defence were dysregulated in reproductive tissues of older rabbits, which is consistent with changes in embryonic metabolism and stress defence. These data highlight the crucial influence of maternal age on uterine adaptability and embryo development.

Melatonin protects against visible light-induced oxidative stress and promotes the implantation potential of mouse blastocyst in vitro

Improvement of embryo culture media using antioxidant agents could help to improve embryo quality against environmental factors such as visible light and could overcome implantation failures. The usefulness of the melatonin against the effect of light on the expression of the primary implantation receptors, ErbB1 and ErbB4 on pre-implantation mouse embryo was investigated. Two-cell mouse embryos were exposed to the 1600 LUX light for 30 min then randomly divided into 3 groups including: Melatonin-Treated; Luzindole Treated and Simple media as a Control group. After 72-96  The expanded blastocysts were examined for morphological quality of the embryos by Hoechst and propidium iodide staining and for the expression of ErbB1 and ErbB4 by Real-time PCR and immunocytochemistry. The expression of the Sirt3 gene was also assayed. Furthermore, intracellular reactive oxygen species (ROS) levels and the total antioxidant capacity (TAC) were examined by DCFH-DA fluorescence intensity and radical cation respectively. The number of cells in the inner cell mass (ICM) and outer cell mass (OCM) were elevated significantly in the Melatonin-treated group suggesting increased viability and proliferation. Furthermore, we found that melatonin significantly increased the expression levels of ErbB1, ErbB4, and Sirt3 genes, and the protein expression of ErbB1, ErbB4 correlated with intracellular ROS levels and TAC significantly increased after melatonin treatment. Together, these results demonstrate that melatonin could be helpful to improve preimplantation embryos through its effects in decreasing ROS levels and increasing expression of implantation-related genes.

Exposure to environmental concentrations of natural pyrethrins induces hepatotoxicity: Assessment in HepG2 cell lines and zebrafish models

Natural pyrethrins are one variety of botanical pesticide, and are commonly used in organic and ecological agriculture. However, the hepatotoxicity of natural pyrethrins is unknown. In this study, the impact of natural pyrethrins on human HepG2 cells, which are prominent cell model for toxic-induced hepatotoxicity evaluations, was investigated in accordance with the ROS production and the mechanism of DNA damage and repair. And we report the liver toxicity of natural pyrethrins in zebrafish. Our result revealed a significant increase in ROS production, suggesting oxidative stress. Besides, the most notable genotoxic effect of oxidation-induced DNA damage was observed for natural pyrethrins, as detected by neutral comet assay and γH2AX/8-oxoG staining. As revealed by the results, oxidative DNA damage is responsible for the cytotoxic exposure of natural pyrethrins to HepG2 cells in humans. The observed damage is chronic toxicity, which may cause irreversible DNA damage and more severe toxic effects on human HepG2 cells. This can account for the complicated response to DNA impairment. Visual observations of zebrafish liver and oil red staining also demonstrated that natural pyrethrins induced liver degeneration, liver size changes and liver steatosis in zebrafish. In conclusion, the health of humans can be endangered by natural pyrethrins as a result of hepatotoxicity.

Mechanisms of lipid metabolism in uterine receptivity and embryo development

Metabolic regulation plays important roles in embryo development and uterine receptivity during early pregnancy, ultimately influencing pregnancy efficiency in mammals. The important roles of lipid metabolism during early pregnancy have not been fully understood. Here, we described the regulatory roles of phospholipid, sphingolipid, and cholesterol metabolism on early embryo development, implantation, and uterine receptivity through production of cannabinoids, prostaglandins, lysophosphatidic acid, sphingosine-1-phosphate, and steroid hormones. Moreover, the impacts of lipids and fatty acids on embryo development potential and the related epigenetic modifications are also discussed. This review aims to elucidate the modulations of lipid metabolism on uterine receptivity and embryo development, contributing to novel strategies to establish dietary balanced lipids and fatty acids for reducing early embryo loss.

Challenges on the effect of cell phone radiation on mammalian embryos and fetuses: a review of the literature

Cell phones operate with a wide range of frequency bands and emit radiofrequency-electromagnetic radiation (RF-EMR). Concern on the possible health hazards of RF-EMR has been growing in many countries because these RF-EMR pulses may be absorbed into the body cells, directly affecting them. There are some in vitro and in vivo animal studies related to the consequences of RF-EMR exposure from cell phones on embryo development and offspring. In addition, some studies have revealed that RF-EMR from cellular phone may lead to decrease in the rates of fertilization and embryo development, as well as the risk of the developmental anomalies, other studies have reported that it does not interfere with in vitro fertilization or intracytoplasmic sperm injection success rates, or the chromosomal aberration rate. Of course, it is unethical to study the effect of waves generated from cell phones on the forming human embryos. Conversely, other mammals have many similarities to humans in terms of anatomy, physiology and genetics. Therefore, in this review we focused on the existing literature evaluating the potential effects of RF-EMR on mammalian embryonic and fetal development.

Effects of L-carnitine combined with pancreatic kininogenase on thioredoxin 2, thioredoxin reductase 1, and sperm quality in patients with oligoasthenospermia

Background

To study the effects of L-carnitine (LC) combined with pancreatic kininogenase on thioredoxin 2 (Trx 2), thioredoxin reductase 1 (TrxR 1), and sperm quality in patients with oligoasthenospermia.

Methods

A total of 300 male infertility patients with oligoasthenospermia who were treated in the andrology clinic of our hospital from December 2019 to December 2020 were randomly divided into an LC group and combined treatment group, and 50 males with normal semen were selected as a control group. The computer-assisted semen analysis system (CASA) was used to detect the total number, vitality, and forward motility of the sperm before and after treatment, and sperm morphology was detected by the Diff-Quik method of the sperm staining kit. Sperm chromatin dispersion (SCD) method was used to detect sperm DNA fragments, and Western-blot was used to detect the protein expression of Trx 2 and TrxR 1.

Results

There were no significant differences in sperm density, motility rate, forward motile sperm rate, and DNA fragmentation rate in oligoasthenospermia patients before treatment (P>0.05). However, after 1 month of treatment, the sperm density, motility rate, and forward motile sperm rate were all higher than before treatment (P<0.05), while the DNA fragmentation rate was lower than before treatment. At the same time, each index of semen in the combination group was higher than that in the LC group (P<0.05), and the total effective rate in the combination group was significantly higher than in the LC group (P<0.01). The expression of Trx2 protein in oligoasthenospermia patients was significantly increased (P<0.05), while the expression of TrxR1 protein was significantly decreased (P<0.05). After 3 months of treatment, the expression of Trx2 protein was significantly decreased (P<0.05), while the expression of TrxR1 protein was significantly increased (P<0.05).

Conclusions

The results suggest Trx 2 and TrxR 1 may be candidate protein markers for oligoasthenospermia. LC combined with pancreatic kininogenase in the treatment of male oligoasthenospermia can effectively promote sperm maturation, enhance sperm motility, and improve semen quality, which has high application value.

Mitochondrial Sirtuins in Reproduction

Mitochondria act as hubs of numerous metabolic pathways. Mitochondrial dysfunctions contribute to altering the redox balance and predispose to aging and metabolic alterations. The sirtuin family is composed of seven members and three of them, SIRT3-5, are housed in mitochondria. They catalyze NAD+-dependent deacylation and the ADP-ribosylation of mitochondrial proteins, thereby modulating gene expression and activities of enzymes involved in oxidative metabolism and stress responses. In this context, mitochondrial sirtuins (mtSIRTs) act in synergistic or antagonistic manners to protect from aging and aging-related metabolic abnormalities. In this review, we focus on the role of mtSIRTs in the biological competence of reproductive cells, organs, and embryos. Most studies are focused on SIRT3 in female reproduction, providing evidence that SIRT3 improves the competence of oocytes in humans and animal models. Moreover, SIRT3 protects oocytes, early embryos, and ovaries against stress conditions. The relationship between derangement of SIRT3 signaling and the imbalance of ROS and antioxidant defenses in testes has also been demonstrated. Very little is known about SIRT4 and SIRT5 functions in the reproductive system. The final goal of this work is to understand whether sirtuin-based signaling may be taken into account as potential targets for therapeutic applications in female and male infertility.

Effect of antioxidants on preimplantation embryo development in vitro: a review

In vitro culture of the embryo is a useful method to treat infertility that shows embryo potential for selecting the best one to transfer and successfully implantation. However, embryo development in vitro is affected by oxidative stresses such as reactive oxygen species that may damage embryo development. Antioxidants are molecules found in fruits, vegetables, and fish that play an important role in reducing oxidative processes. In the natural environment, there is a physiological antioxidant system that protects embryos against oxidative damage. This antioxidant system does not exist in vitro. Antioxidants act as free radical scavengers and protect cells or repair damage done by free radicals. Various studies have shown that adding antioxidants into embryo culture medium improves embryo development in vitro. This review article emphasizes different aspects of various antioxidants, including types, functions and mechanisms, on the growth improvement of different species of embryos in vitro.

The Anti-oxidative Effects of Encapsulated Cysteamine During Mice In Vitro Matured Oocyte/Morula-Compact Stage Embryo Culture Model: a Comparison of High-Efficiency Nanocarriers for Hydrophilic Drug Delivery-a Pilot Study

Although it is well-recognized that antioxidant nano-encapsulation has many benefits such as minimizing side effects (e.g., high-dose toxicity), the most attention was paid to the hydrophobic antioxidant not hydrophilic. In this regard, we sought to compare two hydrophilic model nanocarriers to deliver the optimal dose of cystamine (Cys) into the in vitro matured oocyte and the first cleavage stages until morula-compact stage embryonic cells. The formation of Cys-loaded solid self-emulsifying lipid (Cys + SLN) and Cys-loaded chitosan shell (Cys-CS-NC) were confirmed by FT-IR and UV-Vis spectrophotometry, dynamic light scattering (DLS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) technologies. In two experiments, the oocytes/presumptive zygotes were cultured under various concentrations of Cys-SLN and Cys-CS-NC. The results of nuclear staining (aceto-orcein and Hoechst 33342), H2DCFDA fluorescent staining, chemiluminescence test, and quantitative reverse transcription-PCR (qRT-PCR) technique as in vitro toxicity studies demonstrated that adding the lowest dose of Cys-encapsulated in both nanocarriers [Cys-SLN (5 μM) and Cys-CS-NC (10 μM)] to maturation or culture medium could accumulate a strong anti-oxidative effect in oocyte/embryo by controlled release and enhanced intracellular penetration of Cys. In comparison, Cys-SLN (5 μM) is more effective than Cys-CS-NC (10 μM) groups to improve the expression of antioxidant genes (SOD, CAT, GPx) or anti-apoptotic (BCL-2) gene and decreased apoptosis (BAX and caspase-3) or intra-/extracellular ROS levels. In a nutshell, both nanocarriers (CS-NC or SLN) can deliver the lowest dose of Cys into the oocyte/embryo, thus encouraging a better expansion of antioxidant genes and enhancing the development of in vitro oocyte/embryo.