Ameliorative effects of Bifidobacterium longum peptide-1 on benzo(α)pyrene induced oxidative damages via daf-16 in Caenorhabditis elegans.

Oxidative stress is implicated in numerous diseases, with benzo(α)pyrene (BaP) known for causing substantial oxidative damage. Bifidobacterium longum (B. longum) is recognized as an antioxidant bacterium for certain hosts, yet its influence on oxidative damages instigated by BaP remains undetermined. In our study, we introduced various strains of Caenorhabditis elegans (C. elegans) to BaP to trigger oxidative stress, subsequently treating them with different forms of B. longum to evaluate its protective effects. Additionally, we explored the role of daf-16 in this context. Our findings indicated that in wild-type N2 C. elegans, B. longum-even in the form of inactivated bacteria or bacterial ultrasonic lysates (BULs)-significantly extended lifespan. BaP exposure notably decreased lifespan, superoxide dismutase (SOD) activity, and motility, while simultaneously down-regulating the expression of reactive oxygen species (ROS)-associated genes (sod-3, sek-1, cat-1) and daf-16 downstream genes (sod-3, ctl-2). However, it significantly increased the ROS level, malondialdehyde (MDA) content, and lipofuscin accumulation and up-regulated another daf-16 downstream gene (clk-1) (P <0.05). Interestingly, when further treated with B. longum peptide-1 (BLP-1), opposite effects were observed, and all the aforementioned indices changed significantly. In the case of RNAi (daf-16) C. elegans, BaP exposure significantly shortened the lifespan (P <0.05), which was only slightly prolonged upon further treatment with BLP-1. Furthermore, the expression of daf-16 downstream genes showed minor alterations in RNAi C. elegans upon treatment with either BaP or BLP-1. In conclusion, our findings suggest that B. longum acts as a probiotic for C. elegans. BLP-1 was shown to safeguard C. elegans from numerous oxidative damages induced by BaP, but these protective effects were contingent upon the daf-16 gene.

Evaluation of the Impact of BaP Exposure on the Gut Microbiota and Allergic Responses in an OVA-Sensitized Mouse Model.

BACKGROUND: Exposure to environmental pollutants, including benzo[a]pyrene (BaP), has been implicated in allergic diseases and intestinal microbiota homeostasis, but the environment-microbiota-immunity triangular relationship and to what extent BaP-induced remodeling of the gut microbiota contributes to intestinal allergic inflammation remain to be established. OBJECTIVES: We investigated the impact of BaP on intestinal allergic inflammation and examined the relationship between this effect and gut microbiota dysbiosis. We explored the potential ability of intestinal bacteria to degrade BaP and alleviate cytotoxicity as a detoxification strategy to counteract the effects of BaP exposure. METHODS: We combined microbiome shotgun metagenomics with animal histological and intestinal allergic inflammatory responses to assess the effects of BaP (50µg/mouse per day) in a 23-d toxicity test in antigen-induced allergic female mice. In addition, genome annotation, quantitative analysis of BaP, and in vitro cytotoxicity-tests using CaCo-2 cells were conducted to infer the role of intestinal bacteria in BaP detoxification. RESULTS: BaP exposure impacted the taxonomic composition and the functional potential of the gut microbiota and aggravated antigen-induced intestinal allergic inflammatory responses. The level of inflammatory cytokines correlated with the abundance of specific bacterial taxa, including Lachnospiraceae bacterium 28-4 and Alistipes inops. We identified 614 bacteria harboring genes implicated in the degradation of BaP, and 4 of these bacterial strains were shown to significantly reduce the cytotoxicity of BaP to CaCo-2 cells in vitro. DISCUSSION: Using allergic female mice as a model, we investigated the relationship between BaP, microbiota, and host immune reactions, highlighting the role of gut bacteria in BaP-aggravated allergic reactions. Our findings offer novel insight toward establishing the causal relationship between BaP exposure and the occurrence of allergic disorders. Identifying gut bacteria that degrade BaP may provide new strategies for ameliorating BaP cytotoxicity. https://doi.org/10.1289/EHP11874.

Ameliorative effect of dandelion (Taraxacum officinale) peptides on benzo(a)pyrene-induced oxidative stress and inflammation in human umbilical vein endothelial cells.

Dandelion (Taraxacum officinale) is widely consumed as a health food and a traditional medicine. However, the protective effect of dandelion bio-active peptides (DPs) against polycyclic aromatic hydrocarbon-induced blood vessel inflammation and oxidative damage is not well documented. In the current study, four novel DPs were isolated using an activity tracking method. The protective activity of the DPs against benzo(a)pyrene (Bap)-induced human umbilical vein endothelial cell (HUVEC) damage was explored. The results indicated that DP-2 [cycle-(Thr-His-Ala-Trp)] effectively inhibited Bap-induced reactive oxygen species (ROS) and malondialdehyde (MDA) overproduction and reinforced antioxidant enzyme activity while inhibiting the production of inflammatory factors in HUVECs. Moreover, DP-2 increased NAD(P)H:quinone oxidoreductase 1, heme oxygenase-1, and nuclear factor E2-releated factor 2 expression levels by activating the PI3K/Akt signaling pathway. In addition, DP-2 attenuated Bap-induced HUVEC apoptosis via the Bcl-2/Bax/cytochrome c apoptotic pathway. These results suggest that DP-2 is a promising compound for protecting HUVECs from Bap-induced inflammatory and oxidative damage.

Ameliorative effect of the probiotic peptide against benzo(α)pyrene-induced inflammatory damages in enterocytes.

Probiotics are living bacteria that provide health benefits to the host when consumed in sufficient quantities. However, the protective effect of the bioactive peptides isolated from the probiotics against benzo(α)pyrene (BaP) induced gastrointestinal injury has never been investigated. The current work used a bio-assay guided technique to identify-four new cyclic peptides in BaP-induced Caco-2 cell culture and mouse colitis model. Lactobacillus rhamnosus cycle (Thr-His-Ala-Trp) peptide-1 (LRCP-1) effectively inhibited BaP-induced epithelial cytokine over-release and intracellular ROS over-production. Simultaneously, LRCP-1 attenuated BaP-induced NAD (P)H: oxidases (NOXs), Matrix metalloproteinases (MMPs) over-expression, respectively. Furthermore, increased NAD (P)H: quinone oxidoreductase 1 (NQO1)/heme oxygenase-1 (HO-1)/nuclear factor E2-related factor 2 (Nrf2) expression and aryl hydrocarbon receptor (AhR) pathway activation induced by the BaP-exposure were also inhibited after the LRCP-1 treatment. Notably, LRCP-1 is a promising agent protecting gastrointestinal epithelial cells from BaP-induced inflammatory and oxidative damages.

Chinese liquor extract attenuates oxidative damage in HepG2 cells and extends lifespan of Caenorhabditis elegans.

Chinese liquor is obtained from various grains by fermentation and complex processes. Chinese liquor contains complex ingredients. However, the low contents and presence of ethanol restricted the flavor substances function study. In current study, a flavor substance, homofuraneol (HOMO) was isolated from the Chinese liquor and the potency against H2O2-induced oxidative damage in HepG2 cells and lifespan-extending ability in Caenorhabditis elegans were explored. Results indicated that HOMO increased the HepG2 cells cytoactive by eliminating excessive intracellular free radicals, upregulating antioxidant enzyme activity and inhibiting the phosphorylation of mitogen-activated protein kinases (MAPKs) pathway. Further study revealed that HOMO extended the lifespan of N2 nematodes under normal and oxidative stress conditions. Moreover, RT-PCR results showed that paraquat activated the expression of PMK-1 and SKN-1 was significantly regulated by HOMO. Of note, our results indicated that HOMO recovered the redox states of HepG2 cells by targeting MAPKs and upregulating the stress resistance of nematodes by modulating the expression of stress-responsive genes, such as DAF-16.

LingZhi oligopeptides amino acid sequence analysis and anticancer potency evaluation.

LingZhi (Ganoderma lucidum) has been used as a therapeutic agent for decades, but the antitumor potency of LingZhi oligopeptides (LZOs) was not well explored. In current study, ten novel LZO amino acid sequences were identified, and anticancer potency was evaluated. We found that LZO-3 [EGHGF] significantly triggered A549 cell apoptosis via mitochondrial dysregulation, as evidenced by caspases activation, mitochondrial membrane potential collapse, Bcl-2/Bax ratio alteration, and cytochrome c release. Further, the down-regulation of Trx/TrxR reductase and the improvement of the MDM2/p53 state also contributed to the LZO-3-induced cell apoptosis. Notably, our findings provide evidence for the novel potency of LZOs, which could be developed as promising chemotherapeutic agents against lung cancer.

Structural characterization of ginseng oligopeptides and anti-aging potency evaluation in Caenorhabditis elegans.

The functions of ginseng polysaccharide have been widely explored, yet, the antiaging activity of ginseng oligopeptides (GOPs) has not been well explored. In the current study, seven novel GOPs were isolated, and their antiaging activity was explored in a Caenorhabditis elegans (C. elegans) model. Of interest, all the GOPs showed lifespan extending effects in C. elegans models. Out of the GOPs treatments, 0.75 mM GOP-1 (EHGEYE) prolonged the N2 nematodes lifespan by 42.5%. Additionally, GOP-1 had a strong free radical-scavenging activity, and up-regulated the survival of the N2 C. elegans under oxidative and thermal stresses. Further study revealed that GOP-1 up-regulated the transcription factor daf-16 and jnk-1 expressions, thus we inferred that GOP-1 promotes the lifespan and stress resistances through a JNK-1-DAF-16 pathway. The current study revealed that the ginseng oligopeptides are potential antiaging agents.

The Incidence of Mosaicism for Individual Chromosome in Human Blastocysts Is Correlated With Chromosome Length.

Mosaicism, known as partial aneuploidies, mostly originates from mitotic errors during the post-zygotic stage; it consists of different cell lineages within a human embryo. The incidence of mosaicism has not been shown to correlate with maternal age, and its correlation with individual chromosome characteristics has not been well investigated. In this study, the results of preimplantation genetic testing for aneuploidy (PGT-A) derived from 4,036 blastocysts (930 IVF couples) were collected from 2015 to 2017. Via next-generation sequencing for comprehensive chromosome screening, embryo ploidy was identified as aneuploid, mosaic, and euploid. Total mosaicism was classified into two categories: "mosaic euploid/aneuploidy" (with mosaic aneuploidy between 20 and 80%) and "mosaic and aneuploidy" (a uniformly abnormal embryo superimposed with mosaic aneuploidies). Frequency of mosaicism was analyzed according to the function of chromosomal lengths, which divides involved chromosomes into three groups: group A (156-249 Mb), group B (102-145 Mb), and group C (51-90 Mb). The results show that the aneuploidy was more frequent in group C than in group A and group B (A: 23.7%, B: 35.1, 41.2%, p < 0.0001), while the mosaicism was more frequent in group A and group B than in group C [(Mosaic euploid/aneuploid) A: 14.6%, B: 12.4%, C: 9.9%, p < 0.0001; (mosaic and aneuploid) A: 21.3%, B: 22.9%, C: 18.9%, p < 0.0001; (Total mosaicism) A: 35.9%, B: 35.3%, C: 28.8%, p < 0.0001]. The significantly higher frequency of aneuploidy was on the shorter chromosome (< 90 Mb), and that of mosaicism was on the longer chromosomes (> 100 Mb). The length association did not reach significance in the patients with advanced age (≥ 36 years), and of the chromosome-specific mosaicism rate, the highest prevalence was on chromosome 14 (5.8%), 1 (5.7%), and 9 (5.6%). Although the length association was observed via group comparison, there may be affecting mechanisms other than chromosomes length. Eventually, twenty patients with mosaic embryo cryotransfers resulted in six live births. No significant correlation was observed between the transfer outcomes and chromosome length; however, the analysis was limited by small sample size.

1,3,5,8-Tetrahydroxy-9H-xanthen-9-one exerts its antiageing effect through the regulation of stress-response genes and the MAPK signaling pathway.

The antioxidative effects of 30 xanthone derivatives (XDs) (XD-n, n = 1-30) in HepG2 cells were evaluated by the cellular antioxidant activity assay. Results showed that all XDs were antioxidants and 1,3,5,8-tetrahydroxy-9H-xanthen-9-one (XD-2) was the most active antioxidant. The all-oxygenated substituted xanthones extended the lifespan of wild-type N2 nematodes under normal culture conditions and XD-2 was the best one. XD-2 eliminated excessive intracellular reactive oxygen species and enhanced the expression levels and activities of the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase. XD-2 inhibited the H2 O2 -increased phosphorylation levels of c-JUN N-terminal kinase, extracellular signal-regulated kinase, and p38 in HepG2 cells. In vivo, XD-2 also extended the lifespan of wild-type N2 nematodes under oxidative stress induced by paraquat, but failed in extending the lifespan of CF1038 (daf-16 deletion) and AY102 (pmk-1 deletion) mutant nematodes. It was revealed by real-time polymerase chain reaction that the genes daf-16, sir-2.1, akt-1, and age-1 were all inhibited by paraquat stimuli, while XD-2 reversed these inhibitions; in contrast, paraquat stimuli upregulated both the skn-1 and pmk-1 genes. However, treatment by XD-2 further increased the levels of both genes. These pieces of evidence implied that XD-2 promotes longevity through endogenous signaling pathways rather than through the antioxidative activity alone. Taken all together, it may be concluded that XD-2 is a promising antiageing agent.

Synthesis and antiageing properties of antioxidant pseudopeptides designed based on the bioisostere principle.

Nineteen antioxidant pseudopeptides were designed and synthesized. They were confirmed as mild antioxidants, in which L1-11 was the most active antioxidant with a cellular antioxidant activity (CAA) value of 5.65 ± 0.64 µmol QE/g, and L1-12 was the second most active one (5.58 ± 0.66 µmol QE/g). The existence of nonnatural amino acids in L1-12 increased its stability. Pretreatment with L1-12 dose-dependently extended the lifespan of Caenorhabditis elegans. L1-12 improved resistance against UVB irradiation, oxidative stress induced by paraquat, and thermal shock. It decreased the reactive oxygen species level and upregulated the superoxide dismutase activity inside C. elegans. This pseudopeptide sensitively enhanced the expressions of the Cat-1 and Nhr-8 genes to reduce oxidative damage, leading to an extension of the lifespan. All the evidence support that L1-12 may probably be a potential antiageing agent.

Retracted Article: Structural characterization of peptides from Locusta migratoria manilensis (Meyen, 1835) and anti-aging effect in Caenorhabditis elegans.

Locusts are a kind of agricultural pest rich in protein and widely eaten by people, yet, the nutritional and antioxidant activities of locust peptide have never been explored. In the current study, the locust peptides (LPs) were isolated from the Locusta migratoria manilensis (Meyen, 1835) and the anti-aging effects on Caenorhabditis elegans (C. elegans) were evaluated. The mean lifespan of C. elegans was significantly extended using LPs with a concentration of 1.0 mg mL-1. Out of the 23 peptides, LP-1, a pentapeptide with The-Phe-Lys-His-Gly sequence, with a concentration of 2.5 mg mL-1 significantly extended the lifespan of the worms by 23.5%. Additionally, LP-1 was observed to be a strong free radical-scavenger which can improve the survival of the C. elegans under oxidative stress, thermal stress and UV radiation. Furthermore, the LP-1 can up-regulate the expression of the transcription factor DAF-16 and jnk-1, suggesting that LP-1 may promote the C. elegans lifespan and stress resistance through a JNK-1-DAF-16 pathway. This study will be significant for the development of locusts and improvement of functional insect peptide production.

Retracted Article: Anti-inflammatory potency of Locusta migratoria manilensis cyclopeptides in mast cells and macrophages.

Locusts are esteemed as a traditional Chinese medicine, as well as tonic foods in Asian countries. While searching for natural anti-inflammatory agents in natural products, we isolated four novel locust cyclopeptides (LCPs) and the results show that [cyclo-(Trp-Leu-His-Thr)]∼LCP-3 has potent anti-inflammatory potency in RAW264.7 and HMC-1 cells under LPS (lipopolysaccharide) stimuli. Furthermore, mechanistic studies show that LCP-3 attenuates pro-inflammatory cytokine (TNF-α, IL-6, IL-1ß, NO and PGE2) expression. Moreover, LCP-3 attenuates inflammatory damage associated with the direct inhibition of iNOS and COX-2 expression. LCP-3 also regulates the MAPK, PI3K/AKT and NF-κB pathways to attenuate LPS-induced damage. Of note, our study first reports the anti-inflammatory potency of LCPs and elucidates their underlying molecular mechanisms.

Retracted Article: Synthesis of xanthone derivatives and anti-hepatocellular carcinoma potency evaluation: induced apoptosis.

Twenty-one xanthone derivatives (XDs) were synthesized by a microwave-assisted technique. Their in vitro inhibition potency against the growth of four cancer cell lines was evaluated. XD-1 ∼ [6,9,10-trihydroxy-3,3-dimethyl-5-(2-methylbut-3-en-2-yl)-3H,7H-pyrano[2,3-c]xanthen-7-one] was confirmed as the most active agent against HepG2 cell line growth with IC50 of 18.6 ± 2.31 µM. Apoptosis analysis indicated different contributions of early/late apoptosis and necrosis to cell death for XD-1. XD-1 arrested HepG2 cells on the G0/G1 phase, as indicated by the decreased expressions of cyclin D and CDK2 and the increased expressions of p21. Western blot implied that XD-1 regulated p53/MDM2 to a better healthier state. Moreover, XD-1-induced cell apoptosis was mitochondrion-mediated, as evidenced by caspase activation and involved the PI3K/AKT/mTOR signaling pathway. All the evidence supports that XD-1 is a significant anti-cancer agent for HCC.

Blueberry extract promotes longevity and stress tolerance via DAF-16 in Caenorhabditis elegans.

Blueberry is rich in bioactive phytochemicals with a wide of range of biological activities and health benefits. However, little is known about their effects on aging. The objectives of this study were to evaluate the effects of supplementation with a blueberry extract (BE) on lifespan and stress resistance using Caenorhabditis elegans (C. elegans) as a model. The mechanisms of these effects were explored using RNAi technology. The mean lifespan of C. elegans treated with BE at 50, 100, and 200 mg mL-1 was significantly increased by 22.2%, 36.5%, and 44.4%, respectively, in a dose-dependent manner. In addition, supplementation with BE improved motility and decreased lipofuscin accumulation. C. elegans pretreated with BE were more resistant than untreated C. elegans to stresses (heat, ultraviolet-B radiation, and paraquat). Treatment with BE resulted in up-regulation of genes related to antioxidant systems, including sod-3, cat-1, mev-1, skn-1, mek-1, nhr-8, and daf-16. Suppression of daf-16 by RNAi shortened the lifespan of C. elegans and inhibited the expression of sod-3, suggesting that BE may regulate sod-3 downstream of daf-16 to extend lifespan and stress resistance. Our findings revealed that, in C. elegans, BE can prolong the lifespan, improve health indexes, and enhance stress resistance.

Incorporation of nitric oxide donor into 1,3-dioxyxanthones leads to synergistic anticancer activity.

Fifty 1,3-dioxyxanthone nitrates (4a ∼ i-n, n = 1-6) were designed and synthesized based on molecular similarity strategy. Incorporation of nitrate into 1,3-dioxyxanthones with electron-donating groups at 6-8 position brought about synergistic anticancer effect. Among them, compound 4g-4 was confirmed the most active agent against HepG-2 cells growth with an IC50 of 0.33 ±â€¯0.06 µM. It dose-dependently increased intramolecular NO levels. This activity was attenuated by either NO scavenger PTIO or mitochondrial aldehyde dehydrogenase (mtADH) inhibitor PCDA. Apoptosis analysis indicated different contributions of early/late apoptosis and necrosis to cell death for different dose of 4g-4. 4g-4 arrested more cells on S phase. Results from Western Blot implied that 4g-4 regulated p53/MDM2 to promote cancer cell apoptosis. All the evidences support that 4g-4 is a promising anti-cancer agent.

DMXAA-pyranoxanthone hybrids enhance inhibition activities against human cancer cells with multi-target functions.

Four 5,6-dimethylxanthone-4-acetic acid (D) and pyranoxanthone (P) hybrids (D-P-n) were design-synthesized based on multi-target-addressed strategy. D-P-4 was confirmed as the most active agent against HepG-2 cell line growth with an IC50 of 0.216 ± 0.031 µM. Apoptosis analysis indicated different contributions of early/late apoptosis/necrosis to cell death for both monomers, the combination (D + P in 1:1 mol ratio) and D-P-4. They all arrested more cells on S phase. Western Blot implied that D-P-4 regulated p53/MDM2 to a better healthy state. Moreover, it improved Bax/Bcl-2 signaling pathway to increase cancer cell apoptosis. In all cases studied, D-P-4 showed the best activity and synergistic effect. All the evidences support that D-P-4 is a better anti-cancer therapy with multi-target functions.

Chinese liquor extract enhances inflammation resistance in RAW 264.7 and reduces aging in Caenorhabditis elegans.

Recent reports have indicated that the ingredients in Chinese liquor possess multiple bioactivities. The objective of this study was to evaluate the potential effects of Chinese liquor extract (CME) on the resistance to inflammation in mononuclear macrophages (RAW 264.7 cell line) and aging in Caenorhabditis elegans (C. elegans). The results showed that CME suppressed key lipopolysaccharide (LPS)-induced pro-inflammatory mediators, tumor necrosis factor-α, and nitric oxide in vitro. Furthermore, CME inhibited activation of mitogen-activated protein kinase (MAPK) and phosphatidylinositol-3 kinase (PI3K)/AKT pathways in LPS-stimulated cells. Further studies also showed that CME improved stress resistance of nematodes under infection conditions. Moreover, CME increased the expression of immune-related genes, such as lys-7. Based on these results, our findings provide mechanistic insights about the protection provided by CME against LPS-induced inflammation in RAW 264.7 cells, namely, inhibition of MAPK and PI3K/AKT pathways, as well as its capability against Pseudomonas aeruginosa- and Staphylococcus aureus-induced aging in C. elegans.

Synthesis of xanthone derivatives and studies on the inhibition against cancer cells growth and synergistic combinations of them.

34 Xanthones were synthesized by microwave assisted technique. Their in vitro inhibition activities against five cell lines growth were evaluated. The SAR has been thoroughly discussed. 7-Bromo-1,3-dihydroxy-9H-xanthen-9-one (3-1) was confirmed as the most active agent against MDA-MB-231 cell line growth with an IC50 of 0.46 ± 0.03 µM. Combination of 3-1 and 5,6-dimethylxanthone-4-acetic acid (DMXAA) showed the best synergistic effect. Apoptosis analysis indicated different contributions of early/late apoptosis and necrosis to cell death for both monomers and the combination. Western Blot implied that the combination regulated p53/MDM2 to a better healthy state. Furthermore, 3-1 and DMXAA arrested more cells on G2/M phase; while the combination arrested more cells on S phase. All the evidences support that the 3-1/DMXAA combination is a better anti-cancer therapy.

Comparison of phytochemical profiles, antioxidant and cellular antioxidant activities of different varieties of blueberry (Vaccinium spp.).

Numerous reports have demonstrated that the consumption of fruits and vegetables is beneficial for the human health. Blueberries, in particular, are rich in phytochemicals including free and bound forming. Phytochemical profiles of 14 varieties of blueberry were compared in this study. 12 compounds were analyzed and had significant changes in blueberry fruits. Total antioxidant activities in different blueberry varieties varied about 2.6times by oxygen radical absorbance capacity (ORAC) assay, and 2times by peroxyl radical scavenging capacity (PSC) assay. The cellular antioxidant activities (CAA) in different varieties varied about 3.9times without phosphate buffer saline (PBS) wash, and 4.7times with PBS wash by CAA assay. Blueberry extracts had potent antiproliferative activities against HepG2 human liver cancer cells, indicating the potential protective benefits associated with their use as functional foods. The anti-proliferative activity was observed to be dose-dependent in blueberry extracts.

A Patient Friendly Corifollitropin Alfa Protocol without Routine Pituitary Suppression in Normal Responders.

The release of corifollitropin alfa simplifies daily injections of short-acting recombinant follicular stimulating hormone (rFSH), and its widely-used protocol involves short-acting gonadotropins supplements and a fixed GnRH antagonist regimen, largely based on follicle size. In this study, the feasibility of corifollitropin alfa without routine pituitary suppression was evaluated. A total of 288 patients were stimulated by corifollitropin alfa on cycle day 3 following with routine serum hormone monitoring and follicle scanning every other day after 5 days of initial stimulation, and a GnRH antagonist (0.25 mg) was only used prophylactically when the luteinizing hormone (LH) was ≧ 6 IU/L (over half of the definitive LH surge). The incidence of premature LH surge (≧ 10 IU/L) was 2.4% (7/288) before the timely injection of a single GnRH antagonist, and the elevated LH level was dropped down from 11.9 IU/L to 2.2 IU/L after the suppression. Two hundred fifty-one patients did not need any antagonist (87.2% [251/288]) throughout the whole stimulation. No adverse effects were observed regarding oocyte competency (fertilization rate: 78%; blastocyst formation rate: 64%). The live birth rate per OPU cycle after the first cryotransfer was 56.3% (161/286), and the cumulative live birth rate per OPU cycle after cyrotransfers was 69.6% (199/286). Of patients who did and did not receive GnRH antagonist during stimulation, no significant difference existed in the cumulative live birth rates (78.4% vs. 68.3%, p = 0.25). The results demonstrated that the routine GnRH antagonist administration is not required in the corifollitropin-alfa cycles using a flexible and hormone-depended antagonist regimen, while the clinical outcome is not compromised. This finding reveals that the use of a GnRH antagonist only occasionally may be needed.