Differential role of r-met-hu G-CSF on male reproductive function and development in prepubertal domestic mammals

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Filgrastim (r-met-hu G-CSF) enhances the efficiency of spermatogenesis in prepubertal Bos indicus bulls

This study aimed to test the effects of the drug r-met-hu-G-CSF (filgrastim) on spermatogenic efficiency in prepubertal Brahman bulls. Twelve intact, healthy prepubertal bulls were administered 0, 1 (LD = low dose) or 4 (HD = high dose) µg/Kg r-met-hu-G-CSF (daily for 4 days), and haematological analysis was performed. Bulls were castrated (D0 or D60). BW (body weight) and SC (scrotal circumference) were recorded. Testis weight and volume were taken at castration with samples for testis histology and stereology: germ cell types, spermatids count and DSP (daily sperm production per gram)/g of testicular parenchyma. Testicular weight, volume, BW, SC and gonadosomatic index (GSI) were NS (LD-HD; p > .05). At D0 (age 11 months), the most advanced germ cell types (maGCt) ranged from intermediate spermatogonia to pachytene spermatocytes. After 2 months, control animals had round spermatids as maGCt, LD animals 75% round spermatids and 25% elongated spermatids, and HD animals round spermatids. Spermatids/testis were higher in LD (1.23 ± 0.2 millions) than in controls (0.65 ± 0.1 millions, p < .05). Spermatogenic efficiency (DSP/g) was higher in LD (5.4 ± 0.4 million) than in controls (3.2 ± 0.2 million, p < .01). In conclusion, r-met-hu-G-CSF raises spermatogenic efficiency in prepubertal Brahman bulls.

Effect of Filgrastim on adult male rats' fertility and reproductive performance

Filgrastim is a recombinant protein used in treatment neutropenia caused by myelosuppressive medications for patients with non-myeloid cancer. However, its effect in male fertility is not clear. So, the current work aims to clarify the effect of Filgrastim on the reproductive state in Wistar rats. Eighteen (18) male Wistar rats were divided into three groups (6/each). Group (I) where the rats were injected with 0.5 ml/kg/day of distilled water and served as Control Group. The Group (II) animals received intraperitoneal injection of therapeutic dose of 30.83 mcg/kg/day of Filgrastim for one week. The Group (III) rats received the same dose by the same route of Filgrastim for two weeks. Sera of blood samples were processed for serum follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone (TS). Semen analysis and resazurine reduction test (RRT) were performed. Assaying for malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) was done. The testes were retrieved for histopathological and immunohistochemical studies for caspase-3 detection. Our results revealed that filgrastim affects sperm morphology, significantly decreased the RRT and the reproductive hormones level, elevated the oxidative stress status and induced several histopathological changes in testes with an increased in immunoexpression of caspase-3 in testes tissues. The results of this work demonstrated that Filgrastim may had a deleterious effect on male fertility.