title: Deviant peri-oestrual hormone patterns affect the epithelium of the uterine tube in repeat-breeder heifers.
abstract: In the bovine reproductive tract, the uterine tube is the critical site for a series of events required for fertilization and early embryonic development. In previous studies, a defined category of subfertile heifers, repeat-breeder heifers (RBH), has presented peri-oestrual disturbances (deviating hormone patterns and follicular dynamics) and uterine maternal-embryonic asynchrony. The present study aimed to investigate if tubal function was also affected, by determination of differences in the morphology of the tubal lining epithelium of RBH (n = 4) in comparison to controls (n = 6) during standing oestrus, studied by light and electron microscopy (SEM/TEM), and relate this to steroid hormone concentrations and receptor distribution in the target tissues. Tissue distribution of oestrogen receptor alpha (ERalpha) and progesterone receptor B (PRB) was quantified using immunohistochemistry. In particular, secretory cells differed in appearance between RBH and controls. The cells were less lumen protruding, microvilli were fewer and smaller and secretory granules in the apical cytoplasm were more numerous in RBH. Furthermore, the tubal epithelium was conspicuously coated with amorphous material. Morphological differences between categories were not explained hormonally or by steroid receptor distribution, except in two heifers from which uterine tubes were obtained after the luteinizing hormone (LH) surge. The isthmic PRB : ERalpha ratio was twice as high in the RBH than in the control. The deviating ultrastructure found in RBH, before and after the LH surge, might influence the tubal microenvironment with effects on gamete transport and final maturation and early embryonic development. The present study confirms that previously recorded perturbations in reproductive physiology in RBH are also manifested in the uterine tube, mainly by a deviating ultrastructure of the lining epithelium.
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences SLU, PO Box 7039, SE-750 07 Uppsala, Sweden. renee.bage@og.slu.se
authors.forename: Renée
authors.initials: R
authors.lastname: Båge
authors.forename: Britt
authors.initials: B
authors.lastname: Masironi
authors.forename: Lena
authors.initials: L
authors.lastname: Sahlin
authors.forename: Heriberto
authors.initials: H
authors.lastname: Rodríguez-Martínez
mesh_terms: D000818:Animals; D001947:Breeding; D002417:Cattle / Q000502:physiology*; D004848:Epithelium / Q000502:physiology / Q000648:ultrastructure; D004958:Estradiol / Q000097:blood; D047628:Estrogen Receptor alpha; D004971:Estrus; D005187:Fallopian Tubes / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D005260:Female; D006728:Hormones / Q000097:blood*; D007150:Immunohistochemistry; D007986:Luteinizing Hormone / Q000378:metabolism; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D011374:Progesterone / Q000097:blood; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D014018:Tissue Distribution
chemical_list: D047628:Estrogen Receptor alpha; D006728:Hormones; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C097314:progesterone receptor B; D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone