Granulocyte-colony stimulating factor does not prevent in vitro cisplatin-induced germ cell reduction in immature human and mouse testis

Gabriele Matilionyte, Grace Forsyth, Jingtao Guo, Michael P. Rimmer, Brian P. Hermann, Richard A. Anderson, Rod T. Mitchell

Currently there are no established fertility preservation options for pre-pubertal boys facing cancer treatment. Granulocyte-colony stimulating factor (G-CSF) treatment has been proposed to be chemoprotective against spermatogonial cell loss in an alkylating chemotherapy model of busulfan treated adult mice. Having previously shown that exposure to the alkylating-like chemotherapy cisplatin resulted in a reduction in germ cell numbers in immature human testicular tissues, we here investigate whether G-CSF would prevent cisplatin-induced germ cell loss in immature human and mouse (fetal and pre-pubertal) testicular tissues. Organotypic in vitro culture systems were utilised to determine the effects of clinically-relevant concentrations of G-CSF in cisplatin-exposed immature testicular tissues. Human fetal (n = 14 fetuses) and mouse pre-pubertal (n = 4 litters) testicular tissue pieces were cultured and exposed to cisplatin or vehicle control for 24 hrs and analysed at 72 and 240 hrs post-exposure. Combined G-CSF and cisplatin exposure groups explored varying concentrations and duration of G-CSF supplementation to the culture medium (including groups receiving G-CSF before, during and after cisplatin exposure). In addition, effects of G-CSF supplementation alone were investigated. Survival of total germ cell and sub-populations were identified by expression of AP2γ and MAGE-A4 for human gonocytes and (pre)spermatogonia, respectively, and MVH and PLZF, for mouse germ cells and putative spermatogonial stem cells (SSCs) respectively, were quantified. Exposure to cisplatin resulted in a reduced germ cell number in human fetal and mouse pre-pubertal testicular tissues at 240 hrs post-exposure. Germ cell number was not preserved by combined exposure with G-CSF using any of the exposure regimens (prior to, during or after cisplatin exposure). Continuous supplementation with G-CSF alone for 14 days did not change the germ cell composition in either human or mouse immature testicular tissues. This study demonstrates that exposure to G-CSF does not prevent cisplatin-induced germ cell loss in immature human and mouse testicular tissues in an in vitro system.