RESUMO
Recently, IL-18 was identified in human testes. Moreover, an inverse correlation was found between the levels of IL-18 and the number and motility of spermatozoa. We examined the presence of IL-18 protein in normal and impaired spermatogenesis. Testicular tissue specimens were taken from 25 nonobstructive azoospermic patients undergoing testicular sperm extraction and from autopsies of three healthy controls. The presence of IL-18 in human testicular cells was examined by immunohistochemical staining of paraffin-embedded sections, using a specific antibody for human IL-18. In testicular tissue of healthy controls as well as in study cases, presence of IL-18 was identified in somatic, mitotic, meiotic and post-meiotic cells in correlation with their presence. In all patients, Leydig cells were less intensively stained. Mitotic cells were immunostained in the control group and less intensively in hypospermatogenesis and maturation arrest subgroups. Primary spermatocytes were in general most efficiently stained. The expression of IL-18 mRNA (as examined by real-time PCR analysis) showed significantly lower expression in testicular tissues with impaired spermatogenesis when compared to normal tissues. We report the first study demonstrating the presence of IL-18 in human testicular tissue at the protein level. The presence of this cytokine in somatic as well as in different types of germ cells may suggest its involvement in the regulation of the spermatogenic process and steroidogenesis under physiological and pathological conditions.
Assuntos
Fertilidade/imunologia , Infertilidade Masculina/imunologia , Interleucina-18/metabolismo , Testículo/imunologia , Azoospermia/genética , Azoospermia/imunologia , Sequência de Bases , Estudos de Casos e Controles , Fertilidade/genética , Humanos , Imuno-Histoquímica , Infertilidade Masculina/genética , Interleucina-18/genética , Síndrome de Klinefelter/genética , Síndrome de Klinefelter/imunologia , Masculino , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Síndrome de Células de Sertoli/genética , Síndrome de Células de Sertoli/imunologia , Espermatogênese/imunologiaRESUMO
BACKGROUND: In vitro maturation (IVM) of oocytes is a promising technique to reduce the costs and avert the side effects of gonadotrophin stimulation for IVF. The pregnancy rates from oocytes matured in vitro are still lower than those of in vivo stimulation cycles, indicating that optimization of IVM remains a challenge. Recently, it was demonstrated that LH exerts its action on ovulation, at least in part, through stimulation of the production of the epidermal growth factor family members amphiregulin (Areg) and epiregulin (Ereg) in pre-ovulatory follicles, and they, in turn, serve as paracrine mediators of LH. We aimed to investigate the effect of supplementation of the medium with Areg and Ereg on the maturation rate of immature oocytes. METHODS: A total of 105 sibling human germinal vesicle (GV) oocytes obtained after gonadotrophin stimulation were cultured in a complex defined medium either with or without supplemented recombinant human Areg (75 ng/ml) and Ereg (75 ng/ml) for 24 h. RESULTS: Significantly more oocytes reached the metaphase II stage at 24 h in media supplemented with Areg and Ereg (75.5 versus 36.5%, P < 0.001). In vitro matured oocytes retrieved from the two subgroups had no statistically significant difference in fertilization and cleavage rates or morphology scores. Overall, a significantly higher number of Day 2 (52.8 versus 26.9% P < 0.01) and Day 3 (45.2 versus 23%, P < 0.05) embryos originated from GV oocytes cultured in the Areg- and Ereg-enriched medium. CONCLUSIONS: Supplementation of the maturation medium with Areg and Ereg improves the maturation of human GV oocytes in vitro.
