Eliška Řehůřková works at the RECETOX center as a researcher and doctoral student. Since her master’s studies, she has focused on Cellular and Tissue Toxicology, currently specializes in male reproductive toxicology. In the interview, she explains why she chose toxicology, what she sees as the problem with animal testing, what challenges her field faces, and what causes more and more couples to struggle with reproductive issues.
How did you come to study at RECETOX?
I first studied for a bachelor’s degree in special biology at Masaryk University, but during that time, I was already focusing on ecotoxicology, which interested me the most and was partly conducted here at RECETOX. For my master’s degree, I studied fully at RECETOX, where a new field of Environmental Health was emerging at that time. I wrote my thesis on the topic of Static and Dynamic 3D Cultivation of Human Liver Cell Spheroids under the supervision of Pavel Babica and within the research group of Cellular Toxicology, led by Pavel together with Iva Sovadinová, where I am now also working on my dissertation.
The title of your dissertation is Advanced In Vitro Systems Relevant to Human Health Applicable in Male Reproductive Toxicology and Biomedicine. What does this topic cover?
Simply put, I am developing complex in vitro models, i.e., cellular models that could be used to test the effects of chemicals from our environment on male reproductive health. Specifically, my model is based on the transformation of stem cells into Leydig cells, which are responsible for producing testosterone in the testes. In other words, I am creating a model that could help to test how various chemicals might impact testosterone production in men.
What motivated you to pursue a PhD after completing your master’s degree?
Initially, I didn’t plan to pursue a PhD and continued working at RECETOX as a laboratory technician. It was during this time that I got involved in a project related to reproductive health, which intrigued me, and I was offered the opportunity to continue with a PhD. Since I found the topic interesting and meaningful, I decided to go for it. Reproductive health issues affect a significant portion of the population. I have personally experienced how reproductive problems impact the lives of my loved ones, and I am glad to have the opportunity to contribute to their solution, even if only indirectly.
You mentioned the Cellular and Tissue Toxicology research group led by Pavel Babica and Iva Sovadinová. Could you introduce it a bit more?
Our group studies the effects of chemicals at the cellular and tissue levels. For example, we focus on liver cell models, which play a key role in processing substances we come into contact with. We investigate whether chemicals are toxic to the liver and how liver cells process these substances—some can be neutralized, while others can create toxic intermediates that increase the risk of liver damage and potentially lead to cancer. We also focus on reproduction, particularly on the mentioned testicular cells, which are crucial for sperm production, hormone production, and overall reproductive capability. Testicular cells are sensitive to various chemicals that can affect their function and thus fertility. Additionally, we study various cellular processes, such as cell-to-cell communication.
The group primarily aims to develop in vitro models that could partially replace animal testing. What is your personal view on animal testing?
The question of whether to test on animals is quite complex, and everyone has a slightly different opinion on it. I used to wonder whether it was really necessary to test on animals, whether so many were needed, and I thought about whether they suffer or not and their quality of life. At RECETOX, I learned about the 3R concept, introduced in 1959. This concept states that when using animals in experiments, three principles should be followed: reducing their number as much as possible, replacing animal tests with alternative methods, and improving their conditions to minimize suffering. My work involves developing such an alternative method—a cellular model that would contribute to the principle of replacement. However, it is important to realize that one alternative method will certainly not replace an entire animal experiment. Rather, it would be a whole set of different alternatives.
Is the ethical aspect the main reason why your field is seeking alternatives to animal use?
It is certainly one of the factors, but animal testing also presents other challenges. It is both financially and time-consuming, and as is sometimes said in toxicology, a human is simply not a seventy-kilogram mouse. Due to the different biological processes between these species, there can be significant differences in how chemicals affect humans and mice. Having relevant models that use human cells and show how chemicals affect human processes would therefore be very meaningful.
Let’s return to the issue of reproductive health. What causes fertility problems and how current is this issue?
Since the 1970s, there has been a significant decline in sperm concentration in ejaculate, with some studies reporting a decrease of up to half. This trend has even led to adjustments in the criteria for diagnosing male fertility. Another alarming fact is the rate at which sperm concentration is declining. According to the World Health Organization (WHO), one in six couples faces infertility, which is approximately seventeen percent of the population. The causes of fertility problems are numerous and cannot be attributed to a single factor. We are talking about a combination of genetic predispositions, epigenetic changes, environmental influences, as well as lifestyle and socioeconomic factors. For example, obesity, smoking, stress, sedentary work, or lack of exercise can significantly affect fertility. We live in an environment where we are constantly surrounded by various chemicals, such as pesticides in agricultural products, flame retardants in furniture, or stabilizers in cosmetics. And it is precisely the role of chemicals that I focus on.
What is currently the biggest challenge in your scientific field?
It is certainly the amount of chemicals we currently produce. In the European Union alone, twelve thousand types of chemicals are produced annually in quantities greater than one ton, of which only ten percent have been regulated. This means that we only know the effects on health for ten percent. Overall, there are about 350 million chemicals, and these are only individual substances, not their mixtures. Testing this vast number of substances using traditional animal tests is unrealistic. Prioritizing through in vitro methods could help eliminate at least those substances that are likely to have no effect and focus on those with higher risk.
Do you personally avoid any chemicals as an expert in the field?
Honestly, not much. There are so many chemicals that can affect our health that it’s hard to pick just one to avoid. For example, the plastics we drink from contain substances known to disrupt the hormonal system, especially in women. Yet, they are still commonly used. I think that instead of each individual trying to avoid specific substances, more attention should be paid to their regulation and replacement.
Where do you see yourself in the future? Do you have any plans for your professional career?
I honestly don’t know yet; I’m just happy with what I have now. Currently, I am only in my second year, so I am still studying, attending lectures and exams, but I also supervise my students in the lab and, of course, work on my dissertation. One of the specifics of my field is that we work with cells, which are still living organisms with their own moods and fluctuations, so it can be quite challenging at times. But that’s the case with any PhD study.
What do you enjoy most about science?
What I enjoy most about science is that there is always something new, I am constantly learning, and I am always in contact with people who inspire me in some way.
What do you enjoy the least?
When I work on something for a month and a half and then find out it didn’t work, and I have to start over. But that’s just part of the job in my field (laughs).
Eliska Rehurkova received IFER funding from 2024–2025 for her project, 'Stem Cell-Based Leydig Cell Models for Reprotoxicity Testing and Biomedicine Applications.' Her research aligns with IFER's mission to advance innovative methods that replace and reduce the use of animals in research and testing. To learn more about her project, you can visit the IFER webpage or watch this video.
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