Researchers from Osaka University and Yokohama City University have successfully developed mini-testes organoids from a type of pluripotent stem cell (ES cells) using laboratory techniques. This groundbreaking achievement is expected to establish foundational technology for creating sperm cells in vitro, which has implications for addressing infertility issues and conservation strategies for endangered species. The research team has focused on the intricate processes involved in the development of testes and ovaries, conducting studies aimed at recreating these processes in a controlled environment.

In their previous research conducted in 2021, the team successfully created ovarian organoids by generating precursor cells of eggs and the supporting cells necessary for their development from mouse ES cells. However, attempts to produce testes using male cells led to unexpected outcomes, where the cells differentiated into ovarian structures instead. This prompted further investigation into the mechanisms of sexual differentiation, allowing the researchers to discover a method to suppress the formation of female structures while effectively producing primordial germ cells, the precursors to sperm, from ES cells.

Ultimately, the researchers combined these newly formed cells in culture, resulting in the creation of tiny testes organoids measuring about 0.5 millimeters in size. This development not only showcases the potential for advanced experimentation in reproductive biology but also highlights the possible applications of stem cell technology in understanding reproductive mechanisms and aiding in the restoration of species at risk of extinction.