Long-term ex vivo maintenance of testis tissues producing fertile sperm in a microfluidic device

Abstract

In contrast to cell cultures, particularly to cell lines, tissues or organs removed from the body cannot be maintained for long in any culture conditions. Although it is apparent that in vivo regional homeostasis is facilitated by the microvascular system, mimicking such a system ex vivo is difficult and has not been proved effective. Using the culture system of mouse spermatogenesis, we addressed this issue and devised a simple microfluidic device in which a porous membrane separates a tissue from the flowing medium, conceptually imitating the in vivo relationship between the microvascular flow and surrounding tissue. Testis tissues cultured in this device successfully maintained spermatogenesis for 6 months. The produced sperm were functional to generate healthy offspring with micro-insemination. In addition, the tissue kept producing testosterone and responded to stimulation by luteinizing hormone. These data suggest that the microfluidic device successfully created in vivo-like conditions, in which testis tissue maintained its physiologic functions and homeostasis. The present model of the device, therefore, would provide a valuable foundation of future improvement of culture conditions for various tissues and organs, and revolutionize the organ culture method as a whole.

Neonatal testis growth recreated in vitro by two‐dimensional organ spreading

“…In this microfluidic device, thin tissues obtained nutrients from the culture medium running above them and oxygen through PDMS below. In successful cases, mouse spermatogenesis was maintained for 6 months or beyond (Komeya et al, ). However, there were several drawbacks to that system: high cost, extensive labor, skills in high level, space occupation in an incubator, and a low number of tissues that could be examined at a time.…”

“…We have cultured testis tissues in a microfluidics device made of polydimethylsiloxane (PDMS), which is oxygen permeable (Charati & Stern, ), to improve the culture microenvironment (Komeya et al, ). It actually ameliorated central necrosis, and maintained mouse spermatogenesis for over 6 months.…”

Insights into in vitro spermatogenesis in mammals: Past, present, future

“…The next‐closest system to the testis itself is testicular tissue culture, which is superior to cell culture at producing sperm (Komeya et al, ; Sato, Katagiri, Kubota, & Ogawa, ; Yokonishi et al, ), but requires autologous tissue and poses a complex and uncontrollable model for studying spermatogenesis. The optimum temperature (37°C) and addition of Triiodothyronine and KITLG to the culture media enhances the in vitro differentiation of sperm from testis tissue culture more than twofold (Kim et al, ).…”

Where are Oncofertility and Fertility Preservation Treatments Heading in 2016?

“…The most important criteria for the successful in vitro development of sperm are the culture conditions, including the culture medium used and the incubation temperature [37]. A specialized culture device that utilizes microfluidic techniques to mimic the in vivo environment is also required [38]. This approach may benefit prepubertal boys wishing to father offspring in the future.…”