BMC Seminar Thursday August 24h at 12:00, Læknagarður room 201
Speaker: Dr. Malgorzata Kotula-Balak, Assistant Professor in the Department of Endocrinology, Institute of Zoology, Faculty of Biology and Earth Sciences at the Jagiellonian University, Krakow, Poland
Title: Reproductive physiology of the bank vole - immunohistochemical in vivo and in vitro approaches
Abstract: Bank vole represents seasonally breeding rodent in which function of the reproductive system is controlled by the length of the daylight and melatonin interacting on the hypothalamic-pituitary-gonadal axis. Changes in the activity of reproductive function that appear in spring and autumn correspond to active or regressive phases of the vole reproductive system. In the laboratory, seasonal changes of the photoperiod throughout the year can be mimicked by specific light adjustment, thus, bank voles show similar reproductive characteristics to wild voles.
Our previous studies revealed that gonads of bank voles submitted to short photoperiod produce lower levels of sex hormones due to decreased expression of steroidogenic enzymes e.g. 3β- and 17β-hydroxysteroid dehydrogenases, P450 aromatase. Regardless to the animal age (immature, mature or aged animals) expression of steroidogenic enzymes and receptors (estrogen receptors and androgen receptors) in gonads varied between actively reproducing and regressed animals effecting on gonadal sex steroid hormones production and action. Voles, especially regressed ones, were found to be highly sensitive to changes of androgen and/or estrogen balance within the testes. Estrogen treatment diversely effected on spermatogenesis efficiency in immature and mature animals. Xenoestrogen treatment in turn, resulted in disturbances in tissue cytoarchitecture and blood-testis barrier junctional protein expression (N-cadherin, β-catenin and connexin 43). Modulation of xenoestrogen-treated spermatozoa in vitro fertility parameters e.g. precocious acrosome reaction was observed with the use of lectin immunohistochemistry. Interestingly, vole steroidogenic testicular cells in vitro after xenoestrogen exposure showed marked functional changes that was not the case in transformed steroidogenic cell line.
Nowadays, bank voles are breed only in a few laboratories worldwide. These animals constitute a unique and useful model to explore reproductive system physiology, including the use of immunohistochemistry, in normal and naturally occurring sex hormones withdrawal.
Bio: Dr. Malgorzata Kotula-Balak received an M.S. degree in biology and a Ph.D. degree from the Jagiellonian University in Krakow, Poland, in 1999 and 2003, respectively. She was a Postdoctoral Research Fellow of the Australian Foundation Group of Eight (Go8) at the University of Adelaide (Adelaide, SA, Australia), Laboratory of Molecular Reproduction (Head: Dr. Richard Ivell), and Society, Environment, and Technology Program (Jagiellonian University, Cracow, Poland) at National Institutes of Health (Bethesda, MD, USA), Section on Endocrinology and Genetics (Head: Dr. Constantine A. Stratackis). Dr. Kotula-Balak currently serves as an Assistant Professor (with PhD. DSc. in 2014) in the Department of Endocrinology, Institute of Zoology, Faculty of Biology and Earth Sciences at the Jagiellonian University. She is an academic teacher in endocrinology and animal physiology and Supervisor and Reviewer of B.S. and M.S. degrees theses. She was an executor and co-executor of many research grants and projects. Her research interests are focused on physiology and toxicology of the male reproductive system of animals (e.g. fish, rodents, pig, hores) and human. She is interested in the role of estrogens in testis, mechanisms of estrogen signaling including xenoestrogen action, effects of xenoestrogens on Leydig cells and spermatozoa function. She investigates estrogen signaling via nuclear estrogen receptors (ERs), membrane estrogen receptors (GEPR) and estrogen receptor-related ones (ERRs) in Leydig cells under physiological and pathological testis conditions. Her research was presented during many international conferences on andrology, reproduction, and cyto/histochemistry. She published 42 original papers, book chapters, and monographs. She is acting as a referee for national and international scientific journals. Dr. Kotula-Balak is a Member of the Australian Society for Reproductive Biology, the Polish Society of Andrology, and the Polish Society of Biology of Reproduction.