Icariin stimulates the proliferation of rat Sertoli cells in an ERK1/2-dependent manner in vitro

Research progress of main components from Epimedii Folium (Yinyanghuo) in the treatment of male reproductive dysfunction and application & development status of Epimedii Folium

ETHNOPHARMACOLOGICAL RELEVANCE

Epimedii Folium (Yinyanghuo) is a commonly used Chinese herb that plays a significant role in a lot of herbal formulae used to treat sexual dysfunction. Recently, an increasing amount of research on Epimedii Folium related to male reproductive dysfunction has been reported, and the exploration and application of Epimedium are also expanding rapidly. Flavonoids make up the vast majority of the chemical composition of Epimedii Folium, with small amounts of icarsides series, alkaloids, polysaccharide, volatile oils and other natural compounds. Among them, icariin (ICA) has the highest concentration and the most potent effects on male reproductive dysfunction, icariin II (ICA II), total flavones and polysaccharides from Epimedium have also been reported.

AIM OF STUDY

In this review, we focus on the research progress of the main components from Epimedii Folium in the treatment of male reproductive dysfunction, as well as the application and development status of Epimedii Folium in China, aiming to provide ideas for future in-depth research and product development of Epimedii Folium.

METHODS

On the one hand, we collected literature published from 2003 to May 2024 from various databases, including China National Knowledge Infrastructure (CNKI), the Database of Chinese Sci-Tech Periodicals (VIP), Wanfang Database, Web of Science, Elsevier ScienceDirect, SpringerLink, and the National Center for Biotechnology Information (NCBI) of the USA. On the other hand, we retrieved the data query system of the National Medical Products Administration, Special Food Information Query Platform of the State Administration for Market Regulation, Yaozhi.com, Baidu, China Patent Net, as well as JD.com and Tmall, categorized all epimedia-related products sold in China into medicine, health food, dietary supplements, and animal feed.

RESULTS

A total of 3578 studies were obtained, of which 161 were selected for further analysis. Subsequently, the current status of the main components of Epimedii Folium in the treatment of male reproductive dysfunction was summarized in three sections: research progress on the chemical components of Epimedium, research progress on the pharmacological effects and mechanisms of the main active ingredients, and development and application of the main ingredients of Epimedium.

CONCLUSION

The flavonoids in Epimedii Folium have a beneficial effect on male reproductive dysfunction. However, to date, the primary components of Epimedii Folium have not been directly developed into clinical drugs for treating this condition. This may be due to the lack of a systematic evaluation of their safety. In the field of dietary supplements, products developed using Epimedii Folium as raw materials often face challenges such as low added value and limited international recognition, which hinder its development in the global reproductive health market. We believe that with more in-depth and systematic basic research, Epimedii Folium can make significant contributions to human reproductive health.

Icariin targets PDE5A to regulate viability, DNA synthesis and DNA damage of spermatogonial stem cells and improves reproductive capacity

ABSTRACT

Icariin is a pure compound derived from Epimedium brevicornu Maxim, and it helps the regulation of male reproduction. Nevertheless, the role and underlying mechanisms of Icariin in mediating male germ cell development remain to be clarified. Here, we have demonstrated that Icariin promoted proliferation and DNA synthesis of mouse spermatogonial stem cells (SSCs). Furthermore, surface plasmon resonance iron (SPRi) and molecular docking (MOE) assays revealed that phosphodiesterase 5A (PDE5A) was an important target of Icariin in mouse SSCs. Mechanically, Icariin decreased the expression level of PDE5A. Interestingly, hydrogen peroxides (H2O2) enhanced the expression level of phosphorylation H2A.X (p-H2A.X), whereas Icariin diminished the expression level of p-H2A.X and DNA damage caused by H2O2 in mouse SSCs. Finally, our in vivo animal study indicated that Icariin protected male reproduction. Collectively, these results implicate that Icariin targets PDE5A to regulate mouse SSC viability and DNA damage and improves male reproductive capacity. This study thus sheds new insights into molecular mechanisms underlying the fate decisions of mammalian SSCs and offers a scientific basis for the clinical application of Icariin in male reproduction.

Pharmacological actions of the bioactive compounds of Epimedium on the male reproductive system: current status and future perspective

ABSTRACT

Compounds isolated from Epimedium include the total flavonoids of Epimedium , icariin, and its metabolites (icaritin, icariside I, and icariside II), which have similar molecular structures. Modern pharmacological research and clinical practice have proved that Epimedium and its active components have a wide range of pharmacological effects, especially in improving sexual function, hormone regulation, anti-osteoporosis, immune function regulation, anti-oxidation, and anti-tumor activity. To date, we still need a comprehensive source of knowledge about the pharmacological effects of Epimedium and its bioactive compounds on the male reproductive system. However, their actions in other tissues have been reviewed in recent years. This review critically focuses on the Epimedium , its bioactive compounds, and the biochemical and molecular mechanisms that modulate vital pathways associated with the male reproductive system. Such intrinsic knowledge will significantly further studies on the Epimedium and its bioactive compounds that protect the male reproductive system and provide some guidances for clinical treatment of related male reproductive disorders.

Comprehensive review of the traditional uses and the potential benefits of epimedium folium

Epimedium Folium has been extensively utilized for medicinal purposes in China for a significant period. This review undertakes a comprehensive examination of literature pertaining to Epimedium and its metabolites over the past decade, drawing from databases such as PubMed. Through meticulous organization and synthesis of pertinent research findings, including disease models, pharmacological effects, and related aspects, this narrative review sheds light on the principal pharmacological activities and associated mechanisms of Epimedium in safeguarding the reproductive system, promoting bone health, mitigating inflammation, and combating tumors and viral infections. Consequently, this review contributes to a more profound comprehension of the recent advances in Epimedium research.

Effect of icariin on the transformation efficiency of induced pluripotent stem cells into sperm cells in vitro

OBJECTIVE

To investigate the effect of icariin on the transformation efficiency of germ cell-like cells from mouse induced pluripotent stem cells into sperm cells in vitro.

METHODS

Firstly, mouse induced pluripotent stem cells were induced and cultured to transform into germ cell-like cells, and the primordial germ cell-like cells were identified by Western blot and RT-PCR. Then, different concentrations of icariin (0.1μg/mL, 1μg/mL, 10μg/mL and 100μg/mL) were added into the culture medium, and the obtained primitive germ cell-like cells were cultured, Western blot and RT-PCR were used to identify the obtained sperm cells, the transformation efficiency was compared.

RESULTS

The primordium germ cell-like cells obtained from mouse induced pluripotent stem cells in vitro specially expressed Oct-4 protein, C-kit protein, Mvh mRNA, Fragilis mRNA and Stella mRNA. The sperm cells were specially expressed VASA, SCP3 and γH2AX proteins. RT-PCR showed that the sperm cells were specially expressed Ddx4, Tp2 and Prm1 mRNA. Compared with the control group, the expression level of VASA protein (1.744±0.283, 2.882±0.373, 6.489±0.460), SCP3 protein (2.250±0.306, 7.058±0.521, 8.654±0.804), γH2AX protein (4.304±0.433, 5.713±0.339, 9.268±0.545), Ddx4 mRNA (1.374±0.145, 2.846±0.194, 4.021±0.154), Tp2 mRNA (1.358±0.130, 3.623±0.326, 5.811±0.390) and Prm1 mRNA (1.326±0.162, 3.487±0.237, 4.666±0.307) in 0.1μg/mL, 1μg/mL, 10μg/mL icariin experimental groups were all lower than that of VASA protein (10.560±0.413), SCP3 protein (13.804±0.642), γH2AX protein (11.874±0.464), Ddx4 mRNA (6.4005±0.361), Tp2 mRNA (7.314±0.256) and Prm1 mRNA (7.334±0.390) in 100μg/mL icariin experimental group.

CONCLUSIONS

Icariin can promote the transformation of mouse induced pluripotent stem cells into sperm cells in vitro, and it is concentration-dependent manner in a certain concentration range.

Research progress on the role and mechanism of DNA damage repair in germ cell development

In the complex and dynamic processes of replication, transcription, and translation of DNA molecules, a large number of replication errors or damage can occur which lead to obstacles in the development process of germ cells and result in a decreased reproductive rate. DNA damage repair has attracted widespread attention due to its important role in the maintenance and regulation of germ cells. This study reports on a systematic review of the role and mechanism of DNA damage repair in germline development. First, the causes, detection methods, and repair methods of DNA damage, and the mechanism of DNA damage repair are summarized. Second, a summary of the causes of abnormal DNA damage repair in germ cells is introduced along with common examples, and the relevant effects of germ cell damage. Third, we introduce the application of drugs related to DNA damage repair in the treatment of reproductive diseases and related surgical treatment of abnormal DNA damage, and summarize various applications of DNA damage repair in germ cells. Finally, a summary and discussion is given of the current deficiencies in DNA damage repair during germ cell development and future research development. The purpose of this paper is to provide researchers engaged in relevant fields with a further systematic understanding of the relevant applications of DNA damage repair in germ cells and to gain inspiration from it to provide new research ideas for related fields.

Icariin attenuates perfluorooctane sulfonate-induced testicular toxicity by alleviating Sertoli cell injury and downregulating the p38MAPK/MMP9 pathway

Perfluorooctane sulfonate (PFOS) is widely recognized as causing Sertoli cell injury and testicular toxicity in males. Icariin is a flavonoid from Epimedium, which effectively improves spermatogenesis disturbance induced by several factors in clinic. However, it is unclear whether icariin improves PFOS-induced testicular toxicity. In vivo, fifty-two male mice were randomly separated into four groups: normal control group, model group, and low and high doses of icariin-treated groups, with 13 mice in each group. Except for the normal control group, the mice in the model group and icariin-treated groups were administered PFOS (10 mg kg-1) by gavage daily for 28 consecutive days, and concurrently treated with a diet containing different doses of icariin (0, 5 or 20 mg kg-1). In vitro, TM4 cells were treated with 150 μM PFOS to induce Sertoli cell injury, and were then utilized for icariin treatment. Our results demonstrated that icariin attenuated PFOS-induced testicular toxicity by increasing the testicular, epididymal and seminal vesicle weights, epididymal and seminal vesicle indices, sperm parameters, and seminiferous epithelium height. In addition, icariin improved the PFOS-induced blood-testis barrier (BTB) disruption by alleviating the Sertoli cell junctional injury, but without affecting Sertoli cell numbers in the testis of mice. Moreover, icariin increased the expression levels of tight junction proteins (ZO-1, Occludin and Claudin-11) and gap junction proteins (CX43 and p-CX43), and decreased the expression levels of p-p38MAPK and matrix metalloproteinase 9 (MMP9) both in vivo and in vitro. Furthermore, alleviation of the Sertoli cell injury by icariin exerted similar effects as SB203580 (an inhibitor of p38MAPK) in TM4 cells. This study revealed that icariin effectively reduces PFOS-induced testicular toxicity by alleviating the Sertoli cell injury and downregulating the p38MAPK/MMP9 pathway, indicating that icariin may be an attractive dietary supplement for the intervention of PFOS-induced testicular dysfunction.

Icariin improves testicular dysfunction via enhancing proliferation and inhibiting mitochondria-dependent apoptosis pathway in high-fat diet and streptozotocin-induced diabetic rats

BACKGROUND

Diabetes mellitus (DM), a chronic metabolic disease, severely impairs male reproductive function. However, the underpinning mechanisms are still incompletely defined, and there are no effective strategies or medicines for these reproductive lesions. Icariin (ICA), the main active component extracted from Herba epimedii, is a flavonoid traditionally used to treat testicular dysfunction. Whether ICA can improve male reproductive dysfunction caused by DM and its underlying mechanisms are still unclear. In this study, by employing metformin as a comparative group, we evaluated the protective effects of ICA on male reproductive damages caused by DM and explored the possible mechanisms.

METHODS

Rats were fed with a high fat diet (HFD) and then intraperitoneally injected with streptozotocin (STZ) to induce diabetes. Diabetic rats were randomly divided into T2DM + saline group, T2DM + metformin group and T2DM + ICA group. Rats without the treatment of HFD and STZ were used as control group. The morphology of testicular tissues was examined by histological staining. The mRNA expression levels were determined by quantitative real-time PCR. Immunostaining detected the protein levels of proliferating cell nuclear antigen (PCNA), hypoxia-inducible factor 1-alpha (HIF-1α) and sirtuin 1 (SIRT1) in testicular tissues. TUNEL assay was performed to determine cell apoptosis in the testicular tissues. The protein expression levels of HIF-1α and SIRT1 in the testicular tissues were determined by western blot assay.

RESULTS

ICA effectively improved male reproductive dysfunction of diabetic rats. ICA administration significantly decreased fasting blood glucose (FBG) and insulin resistance index (IRI). In addition, ICA increased testis weight, epididymis weight, sperm number, sperm motility and the cross-sectional area of seminiferous tubule. ICA recovered the number of spermatogonia, primary spermatocytes and Sertoli cells. Furthermore, ICA upregulated the expression of PCNA, activated SRIT1-HIF-1α signaling pathway, and inhibited intrinsic mitochondria dependent apoptosis pathway by upregulating the expression of Bcl-2 and downregulating the expression of Bax and caspase 3.

CONCLUSION

These results suggest that ICA could attenuate male reproductive dysfunction of diabetic rats possibly via increasing cell proliferation and decreasing cell apoptosis of testis. ICA potentially represents a novel therapeutic strategy against DM-induced testicular damages.

Effects of dietary icariin supplementation on the ovary development-related transcriptome of Chinese mitten crab (Eriocheir sinensis)

The Chinese mitten crab (Eriocheir sinensis) is an economically important aquaculture species in China, with distinct differences in ovarian maturation status between crabs fed with natural diets and artificial diets during the listing period, thus, leading to selling price differentiation. Our previous study showed that dietary supplementation with 100 mg/kg icariin can effectively promote ovarian development of E. sinensis. However, the internal molecular mechanism has not yet been elucidated because of a lack of comprehensive genome sequence information. We compared the ovary transcriptomes of E. sinensis fed with two diets containing 0 and 100 mg/kg ICA using the BGISEQ-500 platform. This yielded 12.54 Gb clean bases and 54,794 unigenes, 13,832 of which were found to be differentially expressed after icariin exposure. Twenty pathways closely related to gonadal development were selected through KEGG analysis. Seven differentially expressed genes relevant to vitellogenesis and oocyte maturation (serine/threonine-protein kinase mos-like, Eg2, cytoplasmic polyadenylation element-binding protein, cyclin B, vitellogenin 1, cathepsin D, and juvenile hormone esterase-like carboxylesterase 1) were validated by qRT-PCR, and four proteins (MEK1/2, ERK1/2, Cyclin B and Cdc2) associated with the progesterone mediated oocyte maturation pathway (i.e., MAPK/MPF pathway) were analyzed by western-blot. The results showed that icariin could promote the synthesis, processing and deposition of vitellogenin in oocytes, and that it also has the potential to promote oocyte maturation (resumption of Meiosis I) by altering the expression of the relevant genes and proteins.

Interplay between male reproductive system dysfunction and the therapeutic effect of flavonoids

Male infertility has affected many families around the world. However, due to the mechanism underlying male reproductive system dysfunction are not completely elucidated, the use of drugs for male reproductive system dysfunction treatment only insignificant higher pregnancy outcomes, low-quality evidence suggests that clinical pregnancy rates may increase. Therefore, the focus in the future will be on developing more viable treatment options to prevent or treatment of male reproductive system dysfunction and achieve the purpose of improving fertility. Interestingly, natural products, as the potential inhibitors for the treatment of male reproductive system dysfunction, have shown a good therapeutic effect. Among many natural products, flavonoids have been extensively investigated for the treatment of male reproductive system dysfunction, such as testicular structural disruption, spermatogenesis disturbance and sperm quality decline. Flavonoids have been reported to have antioxidant, anti-inflammatory, immune stimulating, anti-apoptotic, anticarcinogenic, anti-allergic and antiviral activities, investigating for the treatment of male reproductive system dysfunction. In this review, we evaluate the therapeutic effects of flavonoids on male reproductive system dysfunction under different cellular scenarios and summarize the therapeutic strategies of flavonoids based on the aforementioned retrospective analysis. In the end, we describe some perspective research areas relevant to the application of flavonoids in the treatment of male reproductive system dysfunction.

Icariin Improves Age-Related Testicular Dysfunction by Alleviating Sertoli Cell Injury via Upregulation of the ERα/Nrf2-Signaling Pathway

Sertoli cells play crucial roles in spermatogenesis and are impaired by aging. Icariin, a flavonoid from Epimedium, has been reported to exhibit anti-aging effects and improve testicular dysfunction in the clinical setting. However, whether icariin improves age-related degeneration of testicular function via protection from Sertoli cell injury remains unclear. In the present study, we evaluated the protective effect of icariin on Sertoli cell injury and explored the possible mechanism(s) in vivo and in vitro. Dietary administration of icariin for 4 months significantly ameliorated the age-related decline in testicular function by increasing testicular and epididymal weights and indices, sperm count and sperm viability, testicular testosterone and estradiol concentrations, and seminiferous tubule diameters and heights. In addition, icariin protected age-related Sertoli cells from injury as evidenced by an analysis of Sertoli cell number, ultrastructure, and function. Such changes were accompanied by upregulation of ERα and Nrf2 signaling in Sertoli cells. Parallel in vitro studies also demonstrated that icariin inhibited untoward effects on the TM4 mouse Sertoli cell line with concomitant upregulation of ERα and Nrf2 signaling. Conversely, ERα siRNA reversed icariin-mediated protection of Sertoli cell injury. Our data suggest that icariin effectively ameliorates age-related degeneration of testicular function by alleviating Sertoli cell injury via the ERα/Nrf2 signal-transduction pathway. Thus, mitigating Sertoli cell damage via the ERα/Nrf2 signaling pathway likely represents a promising strategy for the prevention of age-related testicular dysfunction.

Icariin attenuate microcystin-LR-induced gap junction injury in Sertoli cells through suppression of Akt pathways

Microcystin-leucine-arginine (MC-LR) can cause male reproductive disorder. However, the underlying mechanism are not yet entirely elucidated. In this study, we aimed to investigated the effects of MC-LR on the integrity of blood-testis barrier (BTB) and the related molecular mechanisms. Both in vivo and in vitro experiments revealed that MC-LR caused disruption of BTB and gap junctions between Sertoli cells respectively, which was paralleled by the alteration of connexin43 (Cx43). Our data demonstrated that MC-LR decreased gap junction intercellular communication (GJIC) and impaired Cx43 expression by activating the phosphatidylinositol 3-kinase/Akt cascades. In addition, a possible protective effect of Icariin (ICA), a flavonoid isolated from Chinese medicinal herb, against MC-LR toxicity was investigated. The ICA prevented the degradation of GJIC and impairment of Cx43 induced by MC-LR via suppressing the Akt pathway. Together, our results confirmed that the expression of Cx43 induced by MC-LR was regulated in vivo and in vitro, which was involved in the destruction of BTB. Additionally, ICA seems to be able to mitigate the MC-LR toxic effects.

Traditional Chinese Medicine as a Remedy for Male Infertility: A Review

Male infertility (MI) is a complex multifactorial disease, and idiopathic infertility accounts for 30% of cases of MI. At present, the evidence for the effectiveness of empirical drugs is limited, and in vitro fertilization is costly and may increase the risk of birth defects and childhood cancers. Therefore, affected individuals may feel obliged to pursue natural remedies. Traditional Chinese medicine (TCM) may represent a useful option for infertile men. It has been demonstrated that TCM can regulate the hypothalamic-pituitary-testicular axis and boost the function of Sertoli cells and Leydig cells. TCM can also alleviate inflammation, prevent oxidative stress, reduce the DNA fragmentation index, and modulate the proliferation and apoptosis of germ cells. Furthermore, TCM can supply trace elements and vitamins, ameliorate the microcirculation of the testis, decrease the levels of serum anti-sperm antibody, and modify epigenetic markers. However, the evidence in favor of TCM is not compelling, which has hindered the development of TCM. This review attempts to elucidate the underlying therapeutic mechanisms of TCM. We also explore the advantages of TCM, differences between TCM and Western medicine, and problems in existing studies. Subsequently, we propose solutions to these problems and present perspectives for the future development of TCM.

The Therapeutic Effects of Traditional Chinese Medicine for Poor Semen Quality in Infertile Males

Poor sperm quality is one of the main factors of male infertility. Traditional Chinese Medicine (TCM) has been used frequently in clinical practice in many countries to treat a wide array of infertile problems. To further understand the effects of TCM on semen quality, we retrospectively enrolled patients with male infertility and poor semen quality at the Tainan Municipal Hospital in Taiwan between 2013 and 2016. Semen quality analysis in accordance with the WHO criteria is an essential step in the evaluation of male fertility status. Associations between the semen parameters and body mass index, smoking status, alcohol use, duration of infertility, and age were also analyzed. A total of 126 male infertility patients with abnormal semen analysis were included in this study: 50 TCM users and 13 TCM non-users. The basic characteristics of the two groups were not significantly different. TCM users account for 92.5% of the total semen improvement subjects. In conclusion, TCM supplementation may have a beneficial role as improving sperm quality for infertility patients.

Icariin Prevents Amyloid Beta-Induced Apoptosis via the PI3K/Akt Pathway in PC-12 Cells

Icariin is a prenylated flavonol glycoside derived from the Chinese herb Epimedium sagittatum that exerts a variety of pharmacological activities and shows promise in the treatment and prevention of Alzheimer's disease. In this study, we investigated the neuroprotective effects of icariin against amyloid beta protein fragment 25–35 (Aβ_25–35) induced neurotoxicity in cultured rat pheochromocytoma PC12 cells and explored potential underlying mechanisms. Our results showed that icariin dose-dependently increased cell viability and decreased Aβ_25–35-induced apoptosis, as assessed by MTT assay and Annexin V/propidium iodide staining, respectively. Results of western blot analysis revealed that the selective phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 suppressed icariin-induced Akt phosphorylation, suggesting that the protective effects of icariin are associated with activation of the PI3K/Akt signaling pathway. LY294002 also blocked the icariin-induced downregulation of proapoptotic factors Bax and caspase-3 and upregulation of antiapoptotic factor Bcl-2 in Aβ_25–35-treated PC12 cells. These findings provide further evidence for the clinical efficacy of icariin in the treatment of Alzheimer's disease.