Ameliorative Effect of Grape Seed Proanthocyanidin Extract on Cadmium-Induced Meiosis Inhibition During Oogenesis in Chicken Embryos

Cadmium as an ovarian toxicant: A review

Cadmium (Cd) is a ubiquitous heavy metal toxicant with no biological function in the human body. Considerably, because of its long biological half-life and very low excretion rate, Cd is inclined to accumulate and cause deleterious effects on various body organs (e.g., liver, kidney, and ovary) in humans and animals. Ovaries are the most vulnerable targets of Cd toxicity. Cd has been shown to induce oxidative stress, follicular atresia, hormonal imbalance, and impairment of oocyte growth and development. Moreover, Cd toxicity has been associated with increasing incidences of menstrual disorders, pregnancy loss, preterm births, delayed puberty, and female infertility. Therefore, it is crucial to understand how Cd poisoning impacts specific ovarian processes for the development of preventive interventions to enhance female fertility. The current review attempts to collate the recent findings on Cd-induced oxidative stress, follicular apoptosis, steroid synthesis inhibition, and teratogenic toxicity, along with their possible mechanisms in the ovarian tissue of different animal species. Additionally, the review also summarizes the studies related to the use of many antioxidants, medicinal herbs, and other compounds as remedial approaches for managing Cd-induced ovarian toxicity.

Impact of grape (Vitis vinifera) seed extract on egg production traits, nutrients digestability, lipid peroxidation and fertility of golden laying hens (Gallus gallus) during early stage of production

Grape by-products represent outstanding alternatives to replace conventional and unsustainable feed sources, given the substantial quantities generated annually by the winery industry. Regrettably, the majority of these by-products are wasted, resulting in significant environmental and economic repercussions. This study was conducted to assess the growth performance, feed efficiency, egg production and quality, lipid peroxidation, fertility and hatchability of reproductive laying hens during their early production stage. A total of 720 golden laying hens, all approximately 25 weeks old and with similar body weights, were randomly assigned to four experimental treatments (six replicates) as follows: control group receiving only the standard diet, (2) a group receiving the standard diet supplemented with grape seed extract at a rate of 250 g/kg (GSE1), (3) a group receiving the standarddiet supplemented with grape seed extract at a rate of 500 g/kg (GSE2), and (4) a group receiving the standarddiet supplemented with grape seed extract at a rate of 750 g/kg (GSE3). There were no significant change (p > 0.05) in feed intak, body weight gain and feed conversion ratio between the control and the experimental groups. Egg weight, egg shell thickness and egg shell weight were significantly (p < 0.05) higher in GSE250 GSE500 and GSE750 compared to the control. The results showed that hen day egg production was also significantly higher (p < 0.05) in GSE500 and GSE 750 compared to the control. Fertility level of GSE 500 and GSE750 was significantly (p < 0.5) higher compared to the control. The MDA level decreased significantly (p < 0.05) in the GSE supplemented birds compared to the control. From these findings, we concluded that GSE 750 had positive impact on egg production, reducing lipid peroxidation and improving fertility in golden laying hens.

Cadmium exposure impairs oocyte meiotic maturation by inducing endoplasmic reticulum stress in vitro maturation of porcine oocytes

Cadmium (Cd) is toxic metal that can induce various diseases, such as cardiovascular, nervous, and reproductive systems. This study investigated the effect of Cd exposure on porcine oocyte maturation and the underlying mechanism. Porcine cumulus-oocyte complexes were exposed various Cd concentration and tauroursodeoxycholic acid (TUDCA), an inhibitor of endoplasmic reticulum (ER) stress during in vitro maturation (IVM). After IVM, we evaluated meiotic maturation, ER stress, and oocyte quality by Cd exposure. Cd exposure inhibited cumulus cell expansion and meiotic maturation, increased oocyte degeneration, and induced ER stress. The levels of spliced XBP1 and ER stress-associated transcripts, markers of ER stress, were elevated in Cd-treated cumulus-oocyte complexes and denuded oocytes during IVM. Moreover, Cd-induced ER stress impaired oocyte quality by disrupting mitochondrial function and elevating intracellular reactive oxygen species levels while decreasing ER function. Interestingly, TUDCA supplementation significantly decreased the expression of ER stress-related genes and increased the quantity of ER compared with the Cd treatment. Additionally, TUDCA was also able to rescue excessive levels of ROS and restore normal mitochondrial function. Moreover, the addition of TUDCA under Cd exposure greatly ameliorated Cd-mediated detrimental effects on meiotic maturation and oocyte quality, including cumulus cell expansion and MII rate. These findings suggest that Cd exposure during IVM impairs the meiotic maturation of oocytes by inducing of ER stress.

Selection of reference genes for RT-qPCR analysis in developing chicken embryonic ovary

BACKGROUND

Normalization of the expression profiling of target genes, in a tissue-specific manner and under different experimental conditions, requires stably expressed gene(s) to be used as internal reference(s). However, to study the molecular regulation of oocyte meiosis initiation during ovary development in chicken embryos, stable reference gene(s) still need to be compared and confirmed.

METHODS AND RESULTS

Six candidate genes previously used as internal references for the chicken embryo (Actb, Cvh, Dazl, Eef1a, Gapdh and Rpl15) were chosen, and their expression profiles in left ovaries dissected at five chicken embryonic days (E12.5, E15.5, E17.5, E18.5 and E20.5) were evaluated, respectively. Separately, GeNorm, NormFinder, BestKeeper and Comparative ΔCt methods were used to assess the stability of candidate reference genes, and all results were combined to give the final rank by RefFinder. All methods identified that Eef1a and Rpl15 were the two most stable internal reference genes, whereas Cvh is the most unstable one. Moreover, expression levels of three marker genes for chicken oocyte meiosis entry (Stra8, Scp3 and Dmc1) were normalized, based on Eef1a, Rpl15, or their combinations, respectively.

CONCLUSION

Our findings provide the most suitable internal reference genes (Eef1a and Rpl15), to investigate further molecular regulation of ovary development and oocyte meiosis initiation in chicken embryos.

Curative Potential of Substances with Bioactive Properties to Alleviate Cd Toxicity: A Review

Rapid urbanization and industrialization have led to alarming cadmium (Cd) pollution. Cd is a toxic heavy metal without any known physiological function in the organism, leading to severe health threat to the population. Cd has a long half-life (10-30 years) and thus it represents serious concern as it to a great extent accumulates in organs or organelles where it often causes irreversible damage. Moreover, Cd contamination might further lead to certain carcinogenic and non-carcinogenic health risks. Therefore, its negative effect on population health has to be minimalized. As Cd is able to enter the body through the air, water, soil, and food chain one possible way to defend and eliminate Cd toxicities is via dietary supplements that aim to eliminate the adverse effects of Cd to the organism. Naturally occurring bioactive compounds in food or medicinal plants with beneficial, mostly antioxidant, anti-inflammatory, anti-aging, or anti-tumorigenesis impact on the organism, have been described to mitigate the negative effect of various contaminants and pollutants, including Cd. This study summarizes the curative effect of recently studied bioactive substances and mineral elements capable to alleviate the negative impact of Cd on various model systems, supposing that not only the Cd-derived health threat can be reduced, but also prevention and control of Cd toxicity and elimination of Cd contamination can be achieved in the future.

Grape Seed Proanthocyanidin Ameliorates FB1-Induced Meiotic Defects in Porcine Oocytes

Fumonisin B₁ (FB₁), as the most prevalent and toxic fumonisin, poses a health threat to humans and animals. The cytotoxicity of FB₁ is closely related to oxidative stress and apoptosis. The purpose of this study is to explore whether Grape seed proanthocyanidin (GSP), a natural antioxidant, could alleviate the meiotic maturation defects of oocytes caused by FB₁ exposure. Porcine cumulus oocyte complexes (COCs) were treated with 30 μM FB₁ alone or cotreated with 100, 200 and 300 μM GSP during in vitro maturation for 44 h. The results show that 200 μM GSP cotreatment observably ameliorated the toxic effects of FB₁ exposure, showing to be promoting first polar body extrusion and improving the subsequent cleavage rate and blastocyst development rate. Moreover, 200 μM GSP cotreatment restored cell cycle progression, reduced the proportion of aberrant spindles, improved actin distribution and protected mitochondrial function in FB₁-exposed oocytes. Furthermore, reactive oxygen species (ROS) generation was significantly decreased and the mRNA levels of CAT, SOD2 and GSH-PX were obviously increased in the 200 μM GSP cotreatment group. Notably, the incidence of early apoptosis and autophagy level were also significantly decreased after GSP cotreatment and the mRNA expression levels of BAX, CASPASE3, LC3 and ATG5 were markedly decreased, whereas BCL2 and mTOR were observably increased in the oocytes after GSP cotreatment. Together, these results indicate that GSP could exert significant preventive effects on FB₁-induced oocyte defects by ameliorating oxidative stress through repairing mitochondrial dysfunction.

A grape seed extract maternal dietary supplementation improves egg quality and reduces ovarian steroidogenesis without affecting fertility parameters in reproductive hens

In broiler hens, the genetic selection increased susceptibility to metabolic disorders and reproductive dysfunctions. In human ovarian cells, grape seed extracts (GSE) improved steroid production. Here, we investigated the effects of a GSE dietary supplementation on egg production and quality, fertility parameters, Reactive Oxygen Species (ROS) and steroid content in yolk egg associated to plasma adipokines in broiler hens. For this, we designed two in vivo experiments, the first one included three groups of hens: A (control), B and C (supplemented with GSE at 0.5% and 1% of the total diet composition, respectively, since week 4), and the second one used two groups of hens: A (control) and D (supplemented with GSE at 1% of the total diet composition since hatching). We assessed the egg production from 23^th to 40^th weeks and quality at 33^th week. After artificial inseminations, the fertility parameters were calculated. In egg yolk, Reactive Oxygen Species (ROS) level and steroid production were evaluated by Ros-Glo H202 and ELISA assay, respectively. Expression of steroidogenic enzymes and adipokines and their receptors was determined by RT-qPCR in ovarian cells and plasma adipokines (RARRES2, ADIPOQ and NAMPT) were evaluated by specific ELISA assays. The fertility parameters and egg production were unaffected by GSE supplementation whatever the experiment (exp.). However, the rate of double-yolk eggs decreased for all GSE supplemented groups (exp. 1 P <0.01, exp.2, P<0.02). In exp.1, C group eggs were bigger and larger (P<0.0001) and the shell elasticity was higher for both B and C (P<0.0003) as compared to control. In the egg yolk, GSE supplementation in both exp. reduced ROS content and steroidogenesis consistent with a decrease in P450 aromatase and StAR mRNA expression and basal in vitro progesterone secretion in granulosa cells (P<0.001). Interestingly, in both exp. RARRES2 plasma levels were positively correlated while ADIPOQ and NAMPT plasma levels were negatively correlated, with steroids and ROS in yolk (P<0.0001). Taken together, maternal dietary GSE supplementation did not affect egg production and fertility parameters whereas it reduced ROS content and steroidogenesis in yolk egg. Furthermore, it ameliorated egg quality by decreasing the number of double-yolk eggs and by improving the size of normal eggs and the elasticity of the shell. Taken together, our data suggest the possibility of using dietary maternal GSE to improve egg quality.

Effects of Grape Seed Extract and Proanthocyanidin B2 on In Vitro Proliferation, Viability, Steroidogenesis, Oxidative Stress, and Cell Signaling in Human Granulosa Cells

Reactive oxygen species (ROS) which lead to oxidative stress affect ovarian function. Grape seed extract (GSE) could be proposed as an effective antioxidant, particularly due to its proanthocyanidin content. In this study, we investigated a dose effect (0, 0.01, 0.1, 1, 10, 50, and 100 μg/mL) of GSE and proanthocyanidin B2 (GSPB2) on the ROS content, cell proliferation, cell viability, and steroidogenesis in both primary luteinized granulosa cells (hGC) and the tumor granulosa cell line (KGN). The levels of ROS were measured using ROS-Glo assay. Cell proliferation and viability were evaluated by [3H]-thymidine incorporation and Cell Counting Kit-8 (CCK8) assay, respectively. Steroid secretion was evaluated by radioimmunoassay. We also analyzed the cell cycle component protein level and signaling pathways by immunoblot and the NOX4 mRNA expression by RTqPCR. From 0.1 to 1 μg/mL, GSE and GSBP2 reduced the ROS cell content and the NOX4 mRNA levels, whereas, GSE and GSBP2 increased the ROS cell content from 50 to 100 μM in both hGC and KGN. GSE and GSPB2 treatments at 50 and 100 μg/mL induced a delay in G₁ to S phase cell cycle progression as determined by fluorescence-activated cell sorting. Consequently, they reduced cell growth, cyclin D2 amount, and Akt phosphorylation, and they increased protein levels of p21 and p27 cyclin-dependent kinase inhibitors. These data were also associated with an increase in cell death that could be due to a reduction in Bcl-2-associated death promoter (BAD) phosphorylation and an increase in the cleaved-caspase-3 level. All these negative effects were not observed at lower concentrations of GSE and GSPB2 (0.01 to 10 μg/mL). Interestingly, we found that GSE and GSPB2 treatments (0.1 to 100 μg/mL) improved progesterone and estradiol secretion and this was associated with a higher level of the cholesterol carriers, StAR (steroidogenic acute regulatory protein), CREB (Cyclic adenosine monophosphate Response Element-binding protein), and MAPK ERK1/2 (Mitogen-Activated Protein Kinases Extracellular signal-Regulated Kinases 1/2) phosphorylation in both hGC and KGN cells. Taken together, GSE and GSPB2 (0.1–10 μg/mL) in vitro treatments decrease oxidative stress and increase steroidogenesis without affecting cell proliferation and viability in human granulosa cells.

Protective effects of zinc and N-acetyl-L-cysteine supplementation against cadmium induced erythrocyte cytotoxicity in Arbor Acres broiler chickens (Gallus gallus domesticus)

Cadmium (Cd) is one of the most toxic metals released into the environment. Here, we investigated the protective role of Zn²⁺ and/or N-acetyl-L-cysteine (NAC) against Cd cytotoxicity in the erythrocytes of Arbor Acres (AA) broiler chickens. Four hundred one-day-old AA chickens were divided into 12 groups for in vitro and in vivo studies. Zn²⁺ and/or NAC was given to the Cd exposed AA chickens to assess their protective roles. This was accomplished by investigating nuclear morphological abnormalities, oxidative stress (SOD, CAT, GPx, GSH and T-AOC), cell apoptosis, ROS accumulation and mitochondrial membrane potential (MMP). Results showed that Cd led to dose- and time-dependent cytotoxicity in the erythrocytes of AA chickens characterized by morphological abnormalities, nucleus damage, increased apoptosis rate and antioxidants depletion. Zn²⁺ or NAC significantly decreased the erythrocyte apoptosis, ROS production and mitochondrial membrane depolarization caused by Cd. SOD, CAT, GPx, GSH and T-AOC activities significantly decreased both in serum and erythrocytes of Cd exposed AA chickens. The supplementation with Zn²⁺ or NAC alleviated Cd induced oxidative stress through promoting SOD or GPx/GSH activities respectively. NAC presented a better role in reducing apoptosis, improving antioxidant activities more than Zn²⁺ in vitro. The combined use of Zn²⁺ and NAC enhanced cytoprotection in Cd exposed erythrocytes of AA chickens compared to Zn²⁺ or NAC alone. In conclusion, Zn²⁺ and NAC exerted remarkable protective roles in Cd exposed erythrocytes of AA chickens by inhibiting cell apoptosis and oxidative stress, and this provides a promising approach to antagonize Cd poisoning in poultry.

Grape Seed Proanthocyanidin Extract Prevents Ovarian Aging by Inhibiting Oxidative Stress in the Hens

Oxidative stress is an important inducement in ovarian aging which results in fecundity decline in human and diverse animals. As a potent antioxidant, grape seed proanthocyanidin extract (GSPE) was investigated to ameliorate chicken ovarian aging in this study. Firstly, ovarian antioxidant capacity of hens at different ages (90, 150, 280, and 580 days old) was compared to elucidate its age-related changes. Subsequently, a D-gal-induced (2.5 mg/mL) aging ovarian model was established and the cultured ovarian tissues were treated with GSPE at 5 μg/mL for 72 h to evaluate the putative attenuating effects of GSPE on ovarian aging. Meanwhile, ovaries of D280 (young) and D580 (old) were treated with GSPE for 72 h in culture to verify the protective effects of GSPE on natural aging ovary. The results showed that GSPE could rescue the antioxidant capacity decline by increasing the antioxidase activities and their gene expression in either D-gal-induced or natural aging ovaries. Moreover, GSPE could maintain the homeostasis between cell proliferation and apoptosis in the D-gal-induced and natural aging ovaries, as well as alleviate D-gal-induced nucleus chromatin condensation in the ovarian granulosa cells. In conclusion, GSPE treatment can effectively prevent the ovarian aging process in hens by reducing oxidative stress.

Protective effect of proanthocyanidin on mice Sertoli cell apoptosis induced by zearalenone via the Nrf2/ARE signalling pathway

This study evaluated the protective effect of proanthocyanidin (PC) on the cytotoxicity of the Sertoli cell TM4 of mice, as induced by zearalenone (ZEA). Flow cytometry was used to detect the apoptosis rate of cells in each group. The activities of antioxidant enzymes and the content of antioxidant substances were detected by using a proprietary kit; the RT-PCR method was used to detect the expression level of mRNA, the related genes of Nrf2/ARE signal pathway, the nuclear factor E2 related factor 2 (Nrf2), heme oxygenase 1 (HO-1), glutathione peroxidase (GSH-Px), quinone oxidoreductase 1 (NQO1), γ-glutamylcysteine synthetase (γ-GCS) and the expression level of mRNA, the apoptosis-related genes, Bcl-2 and Bax; the Western-blot method was used to detect the protein expression levels of Nrf2, GSH-Px, HO-1, γ-GCS and NQO1 in each group. Our results showed that PC could reduce the apoptosis rate of the TM4 cells exposed to ZEA (p < 0.01); PC could enhance the decrease in the activities of T-SOD and GSH-Px induced by ZEA (p < 0.05), reduce the increase in the content of MDA, as caused by ZEA; PC could significantly up-regulate the down-regulation levels of the mRNA and protein of Nrf2, GSH-Px, HO-1, γ-GCS and NQO1 induced by ZEA. PC could enhance the decrease in the mRNA expression level of Bcl-2 and down-regulate the mRNA expression of Bax induced by ZEA (p < 0.05). These results demonstrated that PC conferred protective effects against oxidative damage and apoptosis of TM4 cells induced by ZEA. The protection mechanism of PC on TM4 cells might act through the activation of the Nrf2/ARE signalling pathway.

Proanthocyanidins Attenuation of Chronic Lead-Induced Liver Oxidative Damage in Kunming Mice via the Nrf2/ARE Pathway

Lead is harmful for human health and animals. Proanthocyanidins (PCs), a natural antioxidant, possess a broad spectrum of pharmacological and medicinal properties. However, its protective effects against lead-induced liver damage have not been clarified. This study was aimed to evaluate the protective effect of PCs on the hepatotoxicity of male Kunming mice induced by chronic lead exposure. A total of 70 healthy male Kunming mice were averagely divided into four groups: control group, i.e., the group exposed to lead, the group treated with PCs, and the group co-treated with lead and PCs. The mice exposed to lead were given water containing 0.2% lead acetate. Mice treated in the PCs and PCs lead co-treated groups were given PC (100 mg/kg) in 0.9% saline by oral gavage. Lead exposure caused a significant elevation in the liver function parameters, lead level, lipid peroxidation, and inhibition of antioxidant enzyme activities. The induction of oxidative stress and histological alterations in the liver were minimized by co-treatment with PCs. Meanwhile, the number of Transferase-Mediated Deoxyuridine Triphosphate-Biotin Nick End Labeling (TUNEL)-positive cells was significantly reduced in the PCs/lead co-treated group compared to the lead group. In addition, the lead group showed an increase in the expression level of Bax, while the expression of Bcl-2 was decreased. Furthermore, the lead group showed an increase in the expression level of endoplasmic reticulum (ER) stress-related genes and protein (GRP78 and CHOP). Co-treated with PCs significantly reversed these expressions in the liver. PCs were, therefore, demonstrated to have protective, antioxidant, and anti-ER stress and anti-apoptotic activities in liver damage caused by chronic lead exposure in the Kunming mouse. This may be due to the ability of PCs to enhance the ability of liver tissue to protect against oxidative stress via the Nrf2/ARE signaling pathway, resulting in decreasing ER stress and apoptosis of liver tissue.