Busulfan plus cyclophosphamide induced spermatogenic dysfunction and recovery: A dynamic change perspective

Area of Science:

• Reproductive biology
• Toxicology
• Genomics

Background:

• Busulfan combined with cyclophosphamide (BuCy) is a standard conditioning regimen for hematopoietic stem cell transplantation.
• BuCy causes severe gonadotoxicity, leading to irreversible infertility in nearly half of male patients.
• Existing mouse models often use busulfan alone, not fully replicating clinical BuCy treatment and its effects on male fertility.

Purpose of the Study:

• To longitudinally characterize testicular injury and recovery dynamics following a clinically relevant BuCy treatment regimen in mice.
• To investigate the cellular and molecular mechanisms underlying BuCy-induced testicular damage and partial recovery using single-cell RNA sequencing (scRNA-seq).

Main Methods:

• Administration of a busulfan and cyclophosphamide (BuCy) regimen to a mouse model.
• Longitudinal assessment of testicular histopathology, sperm count, and motility.
• Single-cell RNA sequencing (scRNA-seq) to profile germ cell populations and gene expression changes at multiple time points.

Main Results:

• BuCy treatment induced significant testicular atrophy, disrupted seminiferous tubule structure, and reduced sperm count and motility in mice.
• scRNA-seq revealed a progressive loss of germ cells, with spermatogonia being depleted before spermatogonial stem cells (SSCs).
• A peak in differentially expressed genes (DEGs) was observed at day 28, with functional enrichment indicating disruptions in spermatogenesis, RNA metabolism, and chromatin regulation.

Conclusions:

• This study provides a comprehensive, multi-time-point characterization of BuCy-induced testicular damage and recovery in a mouse model.
• The findings highlight the distinct cellular dynamics of germ cell loss and identify key molecular pathways affected by BuCy treatment.
• This research offers valuable insights into the mechanisms of chemotherapy-induced male infertility and potential avenues for therapeutic intervention.