A Novel Cultivation System for Germ Cell Proliferation and Sustaining Whole Testicular Niche

Area of Science:

• Reproductive biology
• Developmental biology
• Cancer survivorship

Background:

• Childhood cancer treatments can cause male infertility via gonadotoxicity.
• Preserving fertility in prepubertal males is challenging due to limited sperm production capacity.
• Current methods for in vitro testis culture face limitations in expanding sufficient sperm precursors.

Purpose of the Study:

• To develop an advanced in vitro culture system for prepubertal testicular tissue.
• To establish a functional model for expanding the whole testicular spermatogonia pool (WTSP).
• To assess the efficacy of this system in preserving and generating functional sperm for fertility restoration.

Main Methods:

• Development of a hydrogel microneedle-based culture system for mouse testes (5 days postpartum).
• Culture and expansion of undifferentiated spermatogonia within the WTSP model.
• Transplantation of WTSP into nude mice and in vitro meiosis induction.
• Analysis of spermatogonia proliferation and cellular states, including the role of EPHA2 signaling.

Main Results:

• The WTSP system achieved over a fourfold expansion of undifferentiated spermatogonia compared to in vivo decline.
• Transplantation of WTSP significantly increased spermatids count per tubule.
• In vitro meiosis induction successfully generated fertile offspring.
• The system demonstrated successful proliferation of spermatogonia in cultured human fetal gonads.

Conclusions:

• The WTSP system provides a viable method for maintaining and expanding spermatogonia for fertility preservation in prepubertal males.
• This technology holds significant promise for restoring fertility in childhood cancer patients.
• The study identified EPHA2 as a key factor in spermatogonia proliferation via the PI3K-AKT-mTOR pathway.