Reproductive biology最新文献

{"title":"Trps1 targets Scarb1 to regulate cholesterol acquisition in mouse Leydig cells","authors":"Xiuli Lian ,&nbsp;Zihang Lin ,&nbsp;Weitao Hu ,&nbsp;Zhangting Chen ,&nbsp;Shanshan Luo ,&nbsp;Shumin Liao ,&nbsp;Yue Liu ,&nbsp;Shie Wang ,&nbsp;Jiandong Sun","doi":"10.1016/j.repbio.2025.101046","DOIUrl":"10.1016/j.repbio.2025.101046","url":null,"abstract":"<div><div>Approximately 7 % of men are suffering from infertility, accounting for 40 %-50 % of all cases of all infertility, and low testosterone levels are closely associated with male infertility. Our previous study indicated that transcriptional repressor GATA binding 1 (<em>Trps1</em>) could inhibit testosterone synthesis in Leydig cells. In the present study, to elucidate the molecular mechanism by which <em>Trps1</em> regulates testosterone synthesis in Leydig cells, differentially expressed genes (DEGs) following <em>Trps1</em> knockdown was conducted by RNA-sequencing. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis and Genes ontology (GO) analysis were utilized to investigate the pathways associated with <em>Trps1</em>. Gene-silencing technology, Real-Time PCR, and Western blot were performed to validate DEGs. In addition, testosterone and cellular cholesterol content were further observed. We found that GO analysis of DEGs associated with “cholesterol metabolism”. Real-Time PCR and Western blot showed that the expression of steroidogenic factor-1 (<em>Sf-1</em>) and scavenger receptor class B, member 1 (<em>Scarb1</em>) were up-regulated after <em>Trps1</em> silencing. Knockdown of <em>Sf-1</em> and <em>Scarb1</em> could revert the elevated testosterone and cellular cholesterol levels caused by <em>Trps1</em> deficiency. Moreover, ChIP-seq and CUT&amp;Tag-qPCR demonstrated that the promoter of <em>Scarb1</em> has a binding site for SF-1. The present study revealed that TRPS1 exerts regulatory control over the expression of <em>Scarb1</em> by modulating <em>Sf-1</em> transcriptional activity, thereby enhancing cholesterol level and promoting the synthesis of testosterone in Leydig cells.</div></div>","PeriodicalId":21018,"journal":{"name":"Reproductive biology","volume":"25 3","pages":"Article 101046"},"PeriodicalIF":2.5,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144306914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physical activity pattern and Pre-eclampsia risk biomarkers: an observational study","authors":"Ana M. Cagiao ,&nbsp;Pablo Díaz-Brage ,&nbsp;Manuel-Avelino Giráldez ,&nbsp;Marta Torres-Tarrío ,&nbsp;Melissa L. Erickson ,&nbsp;Elvis A. Carnero","doi":"10.1016/j.repbio.2025.101047","DOIUrl":"10.1016/j.repbio.2025.101047","url":null,"abstract":"<div><div>Screening tests for preterm pre-eclampsia (PE) include maternal risk factors, mean arterial blood pressure (MAP), uterine artery pulsatility index (UtA-PI) and serum placental growth factor (PlGF). Exercise interventions have been shown to improve vascular function in pregnant women, which could mediate improvements in angiogenic balance. However, few studies have analyzed how sedentarism and/or physical activity levels are associated with biomarkers of PE. The aim of this study was to analyze the associations between objectively measured physical activity and sedentarism levels with PE risk biomarkers. We hypothesized that higher PA levels would be associated with lower MAP and UtA-PI, and higher PlGF. This was an ancillary study with a convenience sampling from a larger cohort (PREVAL study). Physical activity and sedentarism levels were objectively measured by actigraphy (GT9X Actigraph) in 21 women during the first trimester of pregnancy. We measured PE biomarkers: UtA-PI by ultrasound, PlGF in serum and MAP with a digital sphygmomanometer. The sample was stratified in 2 groups for both physical activity and sedentarism level. Comparisons between groups for PE biomarkers were performed using T-test or Mann Whitney U-test. The level of significance was set at 0.05. PlGF was 57.6 % higher in the active group than in the low-active group (P = 0.018). UtA-PI and MAP were lower in the active group and low-sedentary group although differences were not significant. Moderate-vigorous physical activity (MVPA) was associated with PlGF levels. Therefore, our study suggests a plausible connection between MVPA and biomarkers of PE.</div></div>","PeriodicalId":21018,"journal":{"name":"Reproductive biology","volume":"25 3","pages":"Article 101047"},"PeriodicalIF":2.5,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144313287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Frequent use of methylphenidate causes reduction in sperm production and sperm quality in adult balb/c mice","authors":"Grasielle Avelar Vieira Rodrigues ,&nbsp;Fernanda Carolina Ribeiro Dias ,&nbsp;Elizabeth Lopes de Oliveira ,&nbsp;Ana Luiza Pereira Martins ,&nbsp;Sérgio Luis Pinto da Matta","doi":"10.1016/j.repbio.2025.101043","DOIUrl":"10.1016/j.repbio.2025.101043","url":null,"abstract":"<div><div>Methylphenidate is a psychostimulant used mainly in the treatment of attention deficit hyperactivity disorder (ADHD). The present study evaluated the effects of the drug on the testicles of adult mice, through morphological, histometric, hormonal, and sperm evaluations. Twenty-four Balb /c mice were randomly divided into three experimental groups (n = 8). Group 01: control (distilled water); Group 02: 20 mg/kg/day of methylphenidate; Group 03: 40 mg/kg/day of methylphenidate. The treatment caused a reduction in body weight that may indicate toxic effects caused by prolonged use of the drug. Regarding the percentage of tubular components, there was an increase in the percentage of tubule and epithelium, but the percentage of lumen and tunica propria decreased. The diameters of spermatogonia A and Sertoli cells decreased in stage 1 of the cycle. There were reductions in the percentage of lymphatic space, connective tissue, and macrophages, with a consequent reduction in the percentage of intertubules. Methylphenidate treatment during adulthood decreased plasma testosterone concentrations and compromised the spermatogenic process leading to a reduction in the number of spermatids and spermatozoa, sperm production, and sperm transit time in the epididymis. This allowed us to demonstrate that methylphenidate can impair male fertility.</div></div>","PeriodicalId":21018,"journal":{"name":"Reproductive biology","volume":"25 3","pages":"Article 101043"},"PeriodicalIF":2.5,"publicationDate":"2025-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144296780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morpho-functional and biochemical improvements in ram spermatozoa following intraepididymal platelet-rich plasma administration","authors":"Serap Dayan Cinkara ,&nbsp;Nida Badıllı ,&nbsp;İbrahim Halil Güngör ,&nbsp;Aslıhan Çakır Cihangiroğlu ,&nbsp;Tutku Can Acısu ,&nbsp;Görkem Kırmızıkaya Özmen ,&nbsp;Gözde Arkalı ,&nbsp;Şeyma Özer Kaya ,&nbsp;Mustafa Sönmez ,&nbsp;Seyfettin Gür ,&nbsp;Abdurrauf Yüce ,&nbsp;Ökkeş Yılmaz ,&nbsp;Gaffari Türk","doi":"10.1016/j.repbio.2025.101045","DOIUrl":"10.1016/j.repbio.2025.101045","url":null,"abstract":"<div><div>This study evaluated the effects of intraepididymal platelet-rich plasma (PRP) administration on sperm morpho-functional characteristics and biochemical profiles in rams. Twelve healthy one-year-old Akkaraman rams were randomly assigned to control (0.9 % NaCl) and PRP (0.2 mL/per epididymis; ∼150–200 ×10⁶ platelets) groups, with six biweekly injections. Semen was collected biweekly and subjected to routine spermatological, flow-cytometric and biochemical assessments. PRP treatment significantly enhanced plasma membrane integrity (<em>P</em> &lt; 0.001), total and rapid motility (<em>P</em> &lt; 0.05), and kinematic parameters including VCL (<em>P</em> &lt; 0.05), VSL, VAP, LIN, and WOB (<em>P</em> &lt; 0.01). Significant reductions were observed in head and total abnormalities (<em>P</em> &lt; 0.001), static spermatozoa (<em>P</em> &lt; 0.05), ALH, and BCF (<em>P</em> &lt; 0.05). Flow-cytometric analyses revealed increased proportions of sperm with high mitochondrial activity (<em>P</em> &lt; 0.01), along with decreased acrosomal damage (<em>P</em> &lt; 0.05) and apoptotic spermatozoa (<em>P</em> &lt; 0.001). Biochemical assays demonstrated a marked reduction in malondialdehyde level (<em>P</em> &lt; 0.001) and increased glutathione level, and glutathione-peroxidase and catalase activities (<em>P</em> &lt; 0.01), indicating improved oxidative status. Although a 10.05 % increase in cholesterol level was observed following <em>P</em>RP administration, the change was not statistically significant. However, PRP significantly elevated margaric (C17:0) and stearic (C18:0) acids (<em>P</em> &lt; 0.05–0.01), vaccenic (C18:1n7) and nervonic (C24:1) acids (<em>P</em> &lt; 0.001), and α-linoleic (C18:3n3) and docosapentaenoic (C22:5n3) acids (<em>P</em> &lt; 0.001). These findings suggest that epididymal PRP administration improves sperm quality via enhanced antioxidant capacity, mitochondrial function, and lipid remodeling.</div></div>","PeriodicalId":21018,"journal":{"name":"Reproductive biology","volume":"25 3","pages":"Article 101045"},"PeriodicalIF":2.5,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144262494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Regulatory role of circRNAs in mammalian pregnancy","authors":"Chen Zhou ,&nbsp;Min Qi ,&nbsp;Zhiqian Xu ,&nbsp;Xiaoxia Li ,&nbsp;Junyan Bai ,&nbsp;Youbing Yang","doi":"10.1016/j.repbio.2025.101042","DOIUrl":"10.1016/j.repbio.2025.101042","url":null,"abstract":"<div><div>Circular RNAs (circRNAs) have emerged as key regulators in mammalian pregnancy, influencing crucial processes such as placental development, immune modulation, and hormonal regulation. Their unique covalently closed-loop structure confers exceptional stability, making them ideal candidates as non-invasive biomarkers for monitoring pregnancy progression and diagnosing complications. This review explores the physiological roles of circRNAs during pregnancy, highlighting their involvement in trophoblast invasion, angiogenesis, and maternal-fetal communication. Additionally, it examines the dysregulation of circRNAs in pregnancy-related complications, including pre-eclampsia, gestational diabetes mellitus (GDM), and fetal growth restriction (FGR), where specific circRNAs show potential as early diagnostic markers. Despite promising advances, several challenges remain, such as the need for large-scale validation and standardized detection methods, as well as a deeper understanding of their molecular functions. Addressing these challenges will not only advance reproductive health in humans but also open avenues for improving animal breeding and livestock management through the application of circRNA biomarkers.</div></div>","PeriodicalId":21018,"journal":{"name":"Reproductive biology","volume":"25 3","pages":"Article 101042"},"PeriodicalIF":2.5,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144231777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vitamin D3 and insulin treatment affects porcine follicular fluid-derived extracellular vesicles characteristics and proteome cargo","authors":"Kinga Kamińska ,&nbsp;Bianka Świderska ,&nbsp;Agata Malinowska ,&nbsp;Jakub Barbasz ,&nbsp;Małgorzata Grzesiak","doi":"10.1016/j.repbio.2025.101040","DOIUrl":"10.1016/j.repbio.2025.101040","url":null,"abstract":"<div><div>The study aimed to investigate whether vitamin D₃ and insulin alone or in co-treatment can influence characteristics and protein cargo of the porcine follicular fluid (FF)-derived extracellular vesicles (EVs). To this end, medium antral follicles were cultured <em>in vitro</em> alone (C; control) or with 1α,25(OH)₂D₃ (VD; 100 ng/mL) and insulin (I; 10 ng/mL) separately or in combination (VD+I). The properties of the FF-EVs were assessed by transmission electron microscopy, nanoparticle tracking analysis, electroforetic light scattering, and flow cytometry, while the global proteomic analysis was conducted by liquid chromatography-tandem mass spectrometry coupled with the TMT-isobaric mass tag labeling. In all groups, particles represented a typical cup-shaped morphology, ranged between 50 and 450 nm in diameter, and expressed marker proteins, such as CD63 and CD81. The I treatment decreased the concentration and average size of the FF-EVs, while VD reversed only the effect on the particle concentration. Proteomic analysis revealed 48 differentially abundant proteins (DAPs) between examined groups, whilst greater amount of DAPs was identified following VD and I treatment alone than in co-treatment. Functional analysis showed that VD alone or in combination with I decreased predominantly the abundance of ribosomal proteins. In the I group, proteins involved in oxidative stress were down-regulated. We also found that the FF-EVs are carriers of adiponectin, which was up-regulated in the VD+I group. To sum up, VD and I seem to be novel modulators of the porcine FF-EVs characteristics and protein cargo, and thereby could modify ovarian follicle function <em>via</em> the EV-mediated pathway.</div></div>","PeriodicalId":21018,"journal":{"name":"Reproductive biology","volume":"25 3","pages":"Article 101040"},"PeriodicalIF":2.5,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144195032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distinct roles of Lactobacillus species in trophoblast invasion: Lactobacillus iners fails to promote HTR-8/SVneo cell invasion unlike Lactobacillus crispatus","authors":"Jonghyun Bae ,&nbsp;Kazuhide Takada ,&nbsp;Yoshinori Takeda ,&nbsp;Quang Duy Trinh ,&nbsp;Shihoko Komine-Aizawa ,&nbsp;Dong Wook Kim ,&nbsp;Satoshi Hayakawa","doi":"10.1016/j.repbio.2025.101041","DOIUrl":"10.1016/j.repbio.2025.101041","url":null,"abstract":"<div><div>The role of <em>Lactobacillus iners</em> in the uterus during pregnancy is poorly understood. This study aimed to evaluate the effect of <em>L. iners</em> on trophoblast invasion. The HTR-8/SVneo cell line was cultured with culture supernatants from <em>L. iners</em> (SLI) or <em>L. crispatus</em> (SLC). SLC significantly enhanced HTR-8/SVneo invasion, which was accompanied by increased matrix metalloproteinase-2 mRNA expression, protein expression, and enzymatic activity. In contrast, SLI did not affect trophoblast invasion. These results suggest that the presence of <em>L. iners</em> in the endometrium is less favorable than that of <em>L. crispatus</em> for promoting trophoblast invasion during early pregnancy.</div></div>","PeriodicalId":21018,"journal":{"name":"Reproductive biology","volume":"25 3","pages":"Article 101041"},"PeriodicalIF":2.5,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144195033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chronic stress disturbs neuroendocrine control of reproduction and fertility in male rats","authors":"Habit Medina ,&nbsp;Alejandra Flores ,&nbsp;Lizbeth Juárez-Rojas ,&nbsp;Fahiel Casillas ,&nbsp;Mohammad Mehdi Ommati ,&nbsp;Reza Heidari ,&nbsp;Sara Vázquez ,&nbsp;Denise Clavijo-Cornejo ,&nbsp;Sheila Peña-Corona ,&nbsp;Socorro Retana-Márquez","doi":"10.1016/j.repbio.2025.101027","DOIUrl":"10.1016/j.repbio.2025.101027","url":null,"abstract":"<div><div>Currently, stress is considered one of the risk factors for infertility in male humans, altering sperm function. Sperm production and maturation depends on the hypothalamic-pituitary-testis axis control. Therefore, the objective of the current study was to evaluate the effects of chronic stress on the neuroendocrine control of male reproduction, the oxidative status in the epididymis, and male fertility. Adult male rats were assigned to control or chronic stress groups. Chronically stressed males were exposed to cold-water immersion (CWI) for 50 consecutive days. After euthanasia, the hypothalamus was dissected for Kisspeptin (Kiss1) and Gonadotropin releasing hormone (GnRH) evaluation; serum luteinizing hormone (LH), testosterone (T), and corticosterone concentrations were determined. In the epididymis, reactive oxygen species (ROS), lipid peroxides, and content of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx4) were assessed. Sperm motility, viability, concentration, morphology and acrosomal reaction were assessed. Epididymal sperm were used for in-vitro fertilization with oocytes from intact female rats. Stressed males showed lower hypothalamic Kiss1 and GnRH content, lower LH and T concentration, together with higher serum corticosterone concentration. ROS production, and lipid peroxides increased in all epididymal regions, while SOD, CAT, and GPx4 content decreased after chronic stress; sperm quality was also lower. The percentage of fertilized oocytes decreased, and embryonic development was low, compared to controls. Together, these results show that chronic stress disrupts neuroendocrine control of male reproduction and generates oxidative stress in the epididymis. These effects disturb sperm quality, leading to low fertilizing potential and poor embryonic development.</div></div>","PeriodicalId":21018,"journal":{"name":"Reproductive biology","volume":"25 3","pages":"Article 101027"},"PeriodicalIF":2.5,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144130853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Are BPA effects on Connexins and key downstream microRNAs in bovine COCs correlated to miR-21 expression?","authors":"Thalia M. Goncalves,&nbsp;Olivia L.M. Scandlan,&nbsp;Casi B. Watson,&nbsp;Ola S. Davis,&nbsp;Fiona K. McIlhargey,&nbsp;Reem Sabry,&nbsp;Laura A. Favetta","doi":"10.1016/j.repbio.2025.101026","DOIUrl":"10.1016/j.repbio.2025.101026","url":null,"abstract":"<div><div>Endocrine disrupting compounds such as bisphenol A (BPA) negatively affect oocyte maturation and embryo development, while promoting epigenetic changes in miRNAs (miRs), including that of miR-21. miR-21 is an integral miR involved in various developmental processes, such as oocyte maturation, granulosa cells function and embryo development. Connexin (Cx) gap junction proteins play an important role in the communication among granulosa cells and cumulus cells and are impacted by bisphenols and linked to specific miRs. We hypothesize that miR-21 downregulation and BPA exposure affect Cxs mRNA and downstream miRNAs expression. Oocyte maturation was unaffected by miR-21 downregulation, but was significantly decreased (p = 0.0059) following BPA exposure. Also, BPA significantly increased Cx 43 mRNA levels when miR-21 is knocked-down in cumulus cells (p = 0.0476). miR-378a, a target of Cx 43 and 37, increased due to BPA and combination treatment in denuded oocytes (p = 0.0349) and cumulus cells (p = 0.0177). miR-96, a Cx 26 target, displayed a significant decrease in all samples following BPA exposure, in a miR-21 independent manner (p &lt; 0.05). These data strengthen previous evidence of a strict relationship among BPA, miR-21 and especially Cx 43 and miR-378a. Further investigations are worthy in elucidating these interactions and their response to BPA exposure during early development.</div></div>","PeriodicalId":21018,"journal":{"name":"Reproductive biology","volume":"25 2","pages":"Article 101026"},"PeriodicalIF":2.5,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144099818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polyploidy in germ cell of brown bear Ursus arctos (Ursidae, Mammalia): A case report","authors":"Lianna Virabyan ,&nbsp;Ruzanna Petrosyan ,&nbsp;Irina Ayvazyan ,&nbsp;Emma Rose Khachatrian ,&nbsp;Yana Dombrovskaya ,&nbsp;Varvara Solovyeva ,&nbsp;Victor Spangenberg","doi":"10.1016/j.repbio.2025.101024","DOIUrl":"10.1016/j.repbio.2025.101024","url":null,"abstract":"<div><div>In this work, we present the first detailed study of the normal meiotic karyotype of the brown bear based on the analysis of synaptonemal complexes. Microphotographs of the key stages of meiotic prophase I were obtained. The level of meiotic recombination, features of XY sex bivalent assembly during meiotic prophase I were analyzed. A refined SC karyotype ideogram was constructed, consisting of 37 pachytene bivalents: 36 autosomal bivalents and and XY sex bivalent. We report a rare finding in mammalian germinal cells - a polyploid spermatocyte after genome duplication in the brown bear <em>Ursus arctos</em>. Meiotic tetravalents typical of autotetraploidy, the synaptic configurations consisting of homologous chromosomes and their corresponding duplicated copies, were visualized in this unique nucleus.</div></div>","PeriodicalId":21018,"journal":{"name":"Reproductive biology","volume":"25 2","pages":"Article 101024"},"PeriodicalIF":2.5,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144099819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}