Granulocyte colony-stimulating factor prevents loss of spermatogenesis after sterilizing busulfan chemotherapy

Abstract

Objective: To determine whether granulocyte colony-stimulating factor (G-CSF) could prevent loss of spermatogenesis induced by busulfan chemotherapy via protection of undifferentiated spermatogonia, which might serve as an adjuvant approach to preserving male fertility among cancer patients.

Design: Laboratory animal study.

Setting: University.

Animal(s): Laboratory mice.

Intervention(s): Five-week-old mice were treated with a sterilizing busulfan dose and with 7 days of G-CSF or vehicle treatment and evaluated 10 weeks later (experiment 1) or 24 hours after treatment (experiment 2).

Main outcome measure(s): Experiment 1: testis weights, epididymal sperm counts, testis histology. Experiment 2: PLZF immunofluorescent costaining with apoptotic markers. Molecular analysis of G-CSF receptor expression in undifferentiated spermatogonia.

Result(s): Ten weeks after treatment, busulfan-treated mice that also received treatment with G-CSF exhibited significantly better recovery of spermatogenesis and epididymal sperm counts than animals receiving busulfan alone. G-CSF led to increased numbers of PLZF+ spermatogonia 24 hours after treatment that was not accompanied by changes in apoptosis. To address the cellular target of G-CSF, mRNA for the G-CSF receptor, Csf3r, was found in adult mouse testes and cultured THY1+ (undifferentiated) spermatogonia, and cell-surface localized CSF3R was observed on 3% of cultured THY1+ spermatogonia.

Conclusion(s): These results demonstrate that G-CSF protects spermatogenesis from gonadotoxic insult (busulfan) in rodents, and this may occur via direct action on CSF3R+ undifferentiated spermatogonia. G-CSF treatment might be an effective adjuvant therapy to preserve male fertility in cancer patients receiving sterilizing treatments.

Keywords: Spermatogonial stem cells; cancer therapy; cytokines; fertility preservation; infertility.