A microfluidic testis-on-a-chip system improved the development of spermatogenesis compared to a 3-dimensional methylcellulose in-vitro culture system in a well plate

Introduction: Spermatogenesis is the process of sperm production from spermatogonial stem cells. Chemotherapy may cause irreversible infertility in cancer patients. Prepubertal boys undergoing chemotherapy currently have no option for fertility preservation since they do not produce sperm to be cryopreserved. We previously established a 3-dimensional methylcellulose in-vitro system in a well plate (WP) that induced the development of different stages of spermatogenesis. This research introduces a new testis-on-chip (TOC) and compares it to the WP.

Aim: To establish a novel microfluidic in-vitro system that improves the development of spermatogenesis.

Methodology: Testicular cells isolated from the testes of sexually immature mice were suspended in methylcellulose gel and seeded in the TOC, a microfluidic chip containing channels with culture media that supply nutrition, and, as a control, in a WP. In both systems, the cells were cultured in a methylcellulose gel containing stem-pro media enriched with growth factors for 7 weeks.

Results: The TOC developed larger organoids and both significantly increased cell viability and percentages of meiotic and post-meiotic haploid cells compared to the WP (as verified by immunofluorescence staining and FACS). Confocal imaging showed that organoids in the TOC and WP systems contained seminiferous tubule-like structures with both somatic supporting cells and germ cells in various stages of development.

Conclusions: This research demonstrates the capabilities and advantages of our novel in-vitro microfluidic culture system. Our TOC model outperformed the conventional WP culture and in the future will provide new capabilities such as the dynamic control of the culture environment.