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Home / Equine Research Bank / J Am Vet Med Assoc / Cyclic and pathologic changes of the mare endometrium as det...
Journal of the American Veterinary Medical Association1978; 172(3); 241-262;

Cyclic and pathologic changes of the mare endometrium as detected by biopsy, with a note on early embryonic death.

Abstract: Normal histologic changes that occurred in concert with the ovarian cycle were evaluated. When combined with behavioral and physical findings, this evaluation enabled determination when there was synchrony between ovarian steroids (estrogen and progesterone) and their target tissues of endometrium. A system for classification as well as definitions of patterns types and degrees of severity of inflammatory and fibrotic changes was developed to facilitate a uniform system for description and communication. An attempt was made to relate the pathologic changes to their effect on fertility when fertility was defined as the ability to conceive, maintain, and deliver a live foal. This was done by dividing the types of endometrium into 3 categories, based on increasing degrees of extensiveness and severity of the various changes, and it was possible to show a high correlation of category to foaling rate. Embryonic and fetal loss from endometria with widespread periglandular fibrosis was observed. This was considered to be the major diagnosable cause of this type of reproductive failure.
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Publication Date: 1978-02-01 PubMed ID: 621166
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The study delves into the regular histologic changes associated with the ovarian cycle and observes their connection with reproductive problems in horses, particularly early embryonic death. Using biopsy methods, the research develops a classification system to describe the variations and severity of inflammatory and fibrotic changes in the mare’s endometrium.

Understanding Normal Histologic Changes

  • The study began by examining the regular histologic transformations that coincide with a mare’s ovarian cycle. These physiological changes were assessed in conjunction with behavioral and physical observations.
  • The understanding of these normal changes is critical for determining when there is synchronization between ovarian steroids (i.e., estrogen and progesterone) and their target endometrium tissues. This synchrony is vital for the optimal reproductive health of the mare.

Developing a Classification System

  • Crucial to this study was the development of a unified system for classifying and defining the varying types and severity levels of inflammatory and fibrotic changes identified in the mare’s endometrium.
  • This systematic method of description facilitates clear, concise communication among researchers and practitioners in the field.

Linking Pathologic Changes to Fertility

  • The researchers aimed to connect these pathologic changes in the endometrium to their impact on a mare’s fertility, defined in this context as the ability to conceive, carry, and deliver a live foal.
  • To achieve this, they categorized the endometrium types into three groups, each representing a different level of extensiveness and severity of the identified changes. A strong correlation emerged between these categories and foaling rates.

Observations on Embryonic and Fetal Loss

  • The study found that mares with widespread periglandular fibrosis of the endometrium suffered from embryonic or fetal loss.
  • This condition was deemed the most predominating diagnosable cause of such reproductive failures.

Cite This Article

APA
Kenney RM. (1978). Cyclic and pathologic changes of the mare endometrium as detected by biopsy, with a note on early embryonic death. J Am Vet Med Assoc, 172(3), 241-262.

Publication

Journal of the American Veterinary Medical Association
ISSN: 0003-1488
NlmUniqueID: 7503067
Country: United States
Language: English
Volume: 172
Issue: 3
Pages: 241-262

Researcher Affiliations

Kenney, R M

    MeSH Terms

    • Abortion, Veterinary / pathology
    • Animals
    • Atrophy
    • Bacterial Infections / pathology
    • Bacterial Infections / veterinary
    • Biopsy / methods
    • Biopsy / veterinary
    • Dilatation, Pathologic
    • Embryo, Mammalian
    • Endometrial Hyperplasia / pathology
    • Endometrial Hyperplasia / veterinary
    • Endometritis / pathology
    • Endometritis / veterinary
    • Endometrium / cytology
    • Endometrium / pathology
    • Estrus
    • Female
    • Fertility
    • Fetal Death / pathology
    • Fetal Death / veterinary
    • Horse Diseases / pathology
    • Horses / anatomy & histology
    • Horses / physiology
    • Hypertrophy
    • Pregnancy

    Citations

    This article has been cited 50 times.
    1. Alpoim-Moreira J, Szóstek-Mioduchowska A, Słyszewska M, Rebordão MR, Skarzynski DJ, Ferreira-Dias G. 5-Aza-2'-Deoxycytidine (5-Aza-dC, Decitabine) Inhibits Collagen Type I and III Expression in TGF-β1-Treated Equine Endometrial Fibroblasts. Animals (Basel) 2023 Mar 30;13(7).
      doi: 10.3390/ani13071212pubmed: 37048467google scholar: lookup
    2. Alpoim-Moreira J, Fernandes C, Pimenta J, Bliebernicht M, Rebordão MR, Castelo-Branco P, Szóstek-Mioduchowska A, Skarzynski DJ, Ferreira-Dias G. Metallopeptidades 2 and 9 genes epigenetically modulate equine endometrial fibrosis. Front Vet Sci 2022;9:970003.
      doi: 10.3389/fvets.2022.970003pubmed: 36032279google scholar: lookup
    3. Alpoim-Moreira J, Fernandes C, Rebordão MR, Costa AL, Bliebernicht M, Nunes T, Szóstek-Mioduchowska A, Skarzynski DJ, Ferreira-Dias G. Collagen Type III as a Possible Blood Biomarker of Fibrosis in Equine Endometrium. Animals (Basel) 2022 Jul 21;12(14).
      doi: 10.3390/ani12141854pubmed: 35883401google scholar: lookup
    4. Katila T, Ferreira-Dias G. Evolution of the Concepts of Endometrosis, Post Breeding Endometritis, and Susceptibility of Mares. Animals (Basel) 2022 Mar 19;12(6).
      doi: 10.3390/ani12060779pubmed: 35327176google scholar: lookup
    5. Westendorf J, Wobeser B, Epp T. IIB or not IIB, part 2: assessing inter-rater and intra-rater repeatability of the Kenney-Doig scale in equine endometrial biopsy evaluation. J Vet Diagn Invest 2022 Mar;34(2):215-225.
      doi: 10.1177/10406387211062866pubmed: 34965793google scholar: lookup
    6. Amaral A, Fernandes C, Szóstek-Mioduchowska A, Lukasik K, Rebordão MR, Pinto-Bravo P, Skarzynski DJ, Ferreira-Dias G. The Inhibitory Effect of Noscapine on the In Vitro Cathepsin G-Induced Collagen Expression in Equine Endometrium. Life (Basel) 2021 Oct 19;11(10).
      doi: 10.3390/life11101107pubmed: 34685478google scholar: lookup
    7. Okada CTC, Kaps M, Perez Quesada J, Gautier C, Aurich J, Aurich C. Diestrous Ovulations in Pregnant Mares as a Response to Low Early Postovulatory Progestogen Concentration. Animals (Basel) 2020 Nov 30;10(12).
      doi: 10.3390/ani10122249pubmed: 33266083google scholar: lookup
    8. Amaral A, Fernandes C, Morazzo S, Rebordão MR, Szóstek-Mioduchowska A, Lukasik K, Gawronska-Kozak B, Telo da Gama L, Skarzynski DJ, Ferreira-Dias G. The Inhibition of Cathepsin G on Endometrial Explants With Endometrosis in the Mare. Front Vet Sci 2020;7:582211.
      doi: 10.3389/fvets.2020.582211pubmed: 33195599google scholar: lookup
    9. Miró J, Gutiérrez-Reinoso M, da Silva JA, Fernandes C, Rebordão MR, Alexandre-Pires G, Catalán J, Ferreira-Dias G. Collagen and Eosinophils in Jenny's Endometrium: Do They Differ With Endometrial Classification?. Front Vet Sci 2020;7:631.
      doi: 10.3389/fvets.2020.00631pubmed: 33134338google scholar: lookup
    10. Bukowska J, Szóstek-Mioduchowska AZ, Kopcewicz M, Walendzik K, Machcińska S, Gawrońska-Kozak B. Adipose-Derived Stromal/Stem Cells from Large Animal Models: from Basic to Applied Science. Stem Cell Rev Rep 2021 Jun;17(3):719-738.
      doi: 10.1007/s12015-020-10049-ypubmed: 33025392google scholar: lookup
    11. Szóstek-Mioduchowska A, Leciejewska N, Zelmańska B, Staszkiewicz-Chodor J, Ferreira-Dias G, Skarzynski D. Lysophosphatidic acid as a regulator of endometrial connective tissue growth factor and prostaglandin secretion during estrous cycle and endometrosis in the mare. BMC Vet Res 2020 Sep 17;16(1):343.
      doi: 10.1186/s12917-020-02562-6pubmed: 32943074google scholar: lookup
    12. Schöniger S, Schoon HA. The Healthy and Diseased Equine Endometrium: A Review of Morphological Features and Molecular Analyses. Animals (Basel) 2020 Apr 5;10(4).
      doi: 10.3390/ani10040625pubmed: 32260515google scholar: lookup
    13. Crociati M, Capomaccio S, Mandara MT, Stradaioli G, Sylla L, Monaci M, Cappelli K. Different expression of Defensin-B gene in the endometrium of mares of different age during the breeding season. BMC Vet Res 2019 Dec 21;15(1):465.
      doi: 10.1186/s12917-019-2215-zpubmed: 31864349google scholar: lookup
    14. Klohonatz KM, Coleman SJ, Cameron AD, Hess AM, Reed KJ, Canovas A, Medrano JF, Islas-Trejo AD, Kalbfleisch T, Bouma GJ, Bruemmer JE. Non-Coding RNA Sequencing of Equine Endometrium During Maternal Recognition of Pregnancy. Genes (Basel) 2019 Oct 18;10(10).
      doi: 10.3390/genes10100821pubmed: 31635328google scholar: lookup
    15. Klohonatz KM, Coleman SJ, Islas-Trejo AD, Medrano JF, Hess AM, Kalbfleisch T, Thomas MG, Bouma GJ, Bruemmer JE. Coding RNA Sequencing of Equine Endometrium during Maternal Recognition of Pregnancy. Genes (Basel) 2019 Sep 25;10(10).
      doi: 10.3390/genes10100749pubmed: 31557877google scholar: lookup
    16. de Holanda AGB, da Silva Leite J, Consalter A, da Silva KVGC, Dos Santos Batista BP, Fonseca ABM, Brandão FZ, Ferreira AMR. Expression of interleukins 6 and 10 and population of inflammatory cells in the equine endometrium: diagnostic implications. Mol Biol Rep 2019 Apr;46(2):2485-2491.
      doi: 10.1007/s11033-018-04579-5pubmed: 30900135google scholar: lookup
    17. Klohonatz KM, Nulton LC, Hess AM, Bouma GJ, Bruemmer JE. The role of embryo contact and focal adhesions during maternal recognition of pregnancy. PLoS One 2019;14(3):e0213322.
      doi: 10.1371/journal.pone.0213322pubmed: 30835748google scholar: lookup
    18. Lara E, Rivera N, Cabezas J, Navarrete F, Saravia F, Rodríguez-Alvarez L, Castro FO. Endometrial Stem Cells in Farm Animals: Potential Role in Uterine Physiology and Pathology. Bioengineering (Basel) 2018 Sep 18;5(3).
      doi: 10.3390/bioengineering5030075pubmed: 30231577google scholar: lookup
    19. Rink BE, Beyer T, French HM, Watson E, Aurich C, Donadeu FX. The Fate of Autologous Endometrial Mesenchymal Stromal Cells After Application in the Healthy Equine Uterus. Stem Cells Dev 2018 Aug 1;27(15):1046-1052.
      doi: 10.1089/scd.2018.0056pubmed: 29790424google scholar: lookup
    20. Bramer SA, Macedo A, Klein C. Hexokinase 2 drives glycogen accumulation in equine endometrium at day 12 of diestrus and pregnancy. Reprod Biol Endocrinol 2017 Jan 5;15(1):4.
      doi: 10.1186/s12958-016-0223-4pubmed: 28056994google scholar: lookup
    21. Sikora M, Król J, Nowak M, Stefaniak T, Aubertsson G, Kozdrowski R. The usefulness of uterine lavage and acute phase protein levels as a diagnostic tool for subclinical endometritis in Icelandic mares. Acta Vet Scand 2016 Sep 7;58(1):50.
      doi: 10.1186/s13028-016-0233-4pubmed: 27604098google scholar: lookup
    22. Siemieniuch MJ, Szóstek AZ, Gajos K, Kozdrowski R, Nowak M, Okuda K. Type of Inflammation Differentially Affects Expression of Interleukin 1β and 6, Tumor Necrosis Factor-α and Toll-Like Receptors in Subclinical Endometritis in Mares. PLoS One 2016;11(5):e0154934.
      doi: 10.1371/journal.pone.0154934pubmed: 27152525google scholar: lookup
    23. Debertolis L, Mari G, Merlo B, Merbach S, Schoon HA, Iacono E, Bollwein H. Effects of induced endometritis on uterine blood flow in cows as evaluated by transrectal Doppler sonography. J Vet Sci 2016 Jun 30;17(2):189-97.
      doi: 10.4142/jvs.2016.17.2.189pubmed: 26645345google scholar: lookup
    24. Kendziorski JA, Belcher SM. Strain-specific induction of endometrial periglandular fibrosis in mice exposed during adulthood to the endocrine disrupting chemical bisphenol A. Reprod Toxicol 2015 Dec;58:119-30.
      doi: 10.1016/j.reprotox.2015.08.001pubmed: 26307436google scholar: lookup
    25. Hanada M, Maeda Y, Oikawa MA. Histopathological characteristics of endometrosis in thoroughbred mares in Japan: results from 50 necropsy cases. J Equine Sci 2014;25(2):45-52.
      doi: 10.1294/jes.25.45pubmed: 25013358google scholar: lookup
    26. Mambelli LI, Mattos RC, Winter GH, Madeiro DS, Morais BP, Malschitzky E, Miglino MA, Kerkis A, Kerkis I. Changes in expression pattern of selected endometrial proteins following mesenchymal stem cells infusion in mares with endometrosis. PLoS One 2014;9(6):e97889.
      doi: 10.1371/journal.pone.0097889pubmed: 24901368google scholar: lookup
    27. Hanada M, Maeda Y, Oikawa MA. Equine Endometrial Gland Density and Endometrial Thickness Vary among Sampling Sites in Thoroughbred Mares. J Equine Sci 2012;23(3):35-40.
      doi: 10.1294/jes.23.35pubmed: 24833993google scholar: lookup
    28. Szóstek AZ, Galvão AM, Hojo T, Okuda K, Skarzynski DJ. Interleukins affect equine endometrial cell function: modulatory action of ovarian steroids. Mediators Inflamm 2014;2014:208103.
      doi: 10.1155/2014/208103pubmed: 24719522google scholar: lookup
    29. Buczkowska J, Kozdrowski R, Nowak M, Raś A, Staroniewicz Z, Siemieniuch MJ. Comparison of the biopsy and cytobrush techniques for diagnosis of subclinical endometritis in mares. Reprod Biol Endocrinol 2014 Apr 4;12:27.
      doi: 10.1186/1477-7827-12-27pubmed: 24708825google scholar: lookup
    30. Aresu L, Benali S, Giannuzzi D, Mantovani R, Castagnaro M, Falomo ME. The role of inflammation and matrix metalloproteinases in equine endometriosis. J Vet Sci 2012 Jun;13(2):171-7.
      doi: 10.4142/jvs.2012.13.2.171pubmed: 22705739google scholar: lookup
    31. Kalpokas I, Perdigón F, Rivero R, Talmon M, Sartore I, Viñoles C. Effect of a povidone-iodine intrauterine infusion on progesterone levels and endometrial steroid receptor expression in mares. Acta Vet Scand 2010 Dec 16;52(1):66.
      doi: 10.1186/1751-0147-52-66pubmed: 21162724google scholar: lookup
    32. Higgins R, Messier S, Bada R. Isolation of Gardnerella vaginalis from the genital tract of six mares. Can Vet J 1992 Nov;33(11):745-6.
      pubmed: 17424118
    33. Waelchli RO. Endometrial biopsy in mares under nonuniform breeding management conditions: Prognostic value and relationship with age. Can Vet J 1990 May;31(5):379-84.
      pubmed: 17423587
    34. Bosu WT, Waelchli-Suter RO, Vasey J. Induction of ovulation with gonadotrophin releasing hormone and progesterone in seasonally anestrous mares. Can Vet J 1982 Nov;23(11):332-6.
      pubmed: 17422201
    35. Lefebvre R, Theoret C, Doré M, Girard C, Laverty S, Vaillancourt D. Ovarian teratoma and endometritis in a mare. Can Vet J 2005 Nov;46(11):1029-33.
      pubmed: 16363331
    36. Watt BC, Beck BE. Removal of a nasal polyp in a standing horse. Can Vet J 1997 Feb;38(2):108-9.
      pubmed: 9028595
    37. Leishman D, Miller RB, Doig PA. A quantitative study of the histological morphology of the endometrium of normal and barren mares. Can J Comp Med 1982 Jan;46(1):17-20.
      pubmed: 7200386
    38. Doig PA, McKnight JD, Miller RB. The use of endometrial biopsy in the infertile mare. Can Vet J 1981 Mar;22(3):72-6.
      pubmed: 7026016
    39. Katila T, Lock TF, Ely RW, Smith AR. Morphologic evaluation of acute endometritis in mares with differing resistance to uterine infections. Acta Vet Scand 1986;27(3):378-87.
      doi: 10.1186/BF03548152pubmed: 3565199google scholar: lookup
    40. Katila T. Histology of the post partum equine uterus as determined by endometrial biopsies. Acta Vet Scand 1988;29(2):173-80.
      doi: 10.1186/BF03548368pubmed: 3223466google scholar: lookup
    41. Katila T, Oijala M, Kotilainen T, Väisänen K. Embryo transfer in subfertile mares. Acta Vet Scand 1989;30(3):329-33.
      doi: 10.1186/BF03548039pubmed: 2629508google scholar: lookup
    42. Darenius K. Early foetal death in the mare. Histological, bacteriological and cytological findings in the endometrium. Acta Vet Scand 1992;33(2):147-60.
      doi: 10.1186/BF03547321pubmed: 1502998google scholar: lookup
    43. Vallejo-Soto P, Dorado J, Herrera-García R, Álvarez-Delgado C, Gómez-Laguna J, Santiago Á, Manrique M, González Ariza A, León Jurado JM, Hidalgo M, Ortiz I. Histomorphometric Analysis of the Endometrium of Jennies (Equus asinus) and Mares (Equus caballus) in Estrus: Anatomical Differences and Possible Reproductive Implications. Animals (Basel) 2026 Jan 4;16(1).
      doi: 10.3390/ani16010143pubmed: 41514829google scholar: lookup
    44. Wójtowicz A, Sadowska A, Molcan T, Słyszewska M, Drzewiecka EM, Tobolski D, Ferreira-Dias G, Szóstek-Mioduchowska A. Th1 and Th2 cells in equine endometrosis and their interactions with endometrial fibroblasts. Sci Rep 2025 Oct 16;15(1):36263.
      doi: 10.1038/s41598-025-20152-0pubmed: 41102323google scholar: lookup
    45. Satué K, La Fauci D, Medica P, Velasco-Martínez MG, Barbiera G, Fazio E. Involvement of Peripheral Serotonin in Blood Cells in Healthy Cyclical Mares of Different Ages. Vet Sci 2025 Jun 4;12(6).
      doi: 10.3390/vetsci12060548pubmed: 40559785google scholar: lookup
    46. Piotrowska-Tomala KK, Szóstek-Mioduchowska AZ, Drzewiecka EM, Jonczyk AW, Wójtowicz A, Wrobel MH, Ferreira-Dias G, Skarzynski DJ. Prostaglandin pathways in equine myometrium regulations: endometrosis progression. Front Vet Sci 2024;11:1479508.
      doi: 10.3389/fvets.2024.1479508pubmed: 39735588google scholar: lookup
    47. Piotrowska-Tomala KK, Szóstek-Mioduchowska A, Jonczyk AW, Drzewiecka EM, Wrobel MH, Hojo T, Ferreira-Dias G, Skarzynski DJ. The effect of lysophosphatidic acid on myometrial contractility and the mRNA transcription of its receptors in the myometrium at different stages of endometrosis in mares. BMC Vet Res 2024 Dec 19;20(1):571.
      doi: 10.1186/s12917-024-04384-2pubmed: 39696406google scholar: lookup
    48. Zdrojkowski Ł, Pawliński B, Skierbiszewska K, Jasiński T, Domino M. Assessment of Connective Tissue in the Equine Uterus and Cervix: Review of Clinical Impact and Staining Options. Animals (Basel) 2024 Jan 3;14(1).
      doi: 10.3390/ani14010156pubmed: 38200887google scholar: lookup
    49. Szóstek-Mioduchowska A, Wójtowicz A, Sadowska A, Moza Jalali B, Słyszewska M, Łukasik K, Gurgul A, Szmatoła T, Bugno-Poniewierska M, Ferreira-Dias G, Skarzynski DJ. Transcriptomic profiling of mare endometrium at different stages of endometrosis. Sci Rep 2023 Sep 27;13(1):16263.
      doi: 10.1038/s41598-023-43359-5pubmed: 37758834google scholar: lookup
    50. Wójtowicz A, Molcan T, Lukasik K, Żebrowska E, Pawlina-Tyszko K, Gurgul A, Szmatoła T, Bugno-Poniewierska M, Ferreira-Dias G, Skarzynski DJ, Szóstek-Mioduchowska A. The potential role of miRNAs and regulation of their expression in the development of mare endometrial fibrosis. Sci Rep 2023 Sep 24;13(1):15938.
      doi: 10.1038/s41598-023-42149-3pubmed: 37743390google scholar: lookup
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