Bone Morphogenetic Protein-6 (BMP-6) induces atresia in goat primordial follicles cultured in vitro

Abstract

770Pesq. Vet. Bras. 30(9):770-776, setembro 2010 RESUMO.-[A Proteína Morfogenética Óssea-6 (BMP-6) induz a atresia em folículos primordiais caprinos cultivados in vitro.] O presente estudo investigou os efeitos da proteína morfogenética óssea-6 (BMP-6) no desenvolvimento in vitro de folículos primordiais caprinos. Amostras de córtex ovariano de cabras foram cultivados por 1 ou 7 dias em Meio Essencial Mínimo (meio controle) suplementado com diferentes concentrações de BMP-6. As taxas de sobrevivência, ativação e crescimento foram avaliadas por histologia clássica e microscopia eletrônica de transmissão (MET). Após 7 dias de cultivo, a análise histológica demonstrou que a BMP-6 aumentou o percentual de folículos primordiais degenerados no dia 7 quando comparados ao controle fresco (D0). Além disso, houve um aumento significativo do diâmetro folicular e oocitário em ambos os períodos de cultivo em todos os tratamentos na presença de BMP-6. Com a progressão do cultivo do dia 1 para o dia 7, nos tratamentos com 1 ou 50ng/ml de BMP-6, foi observado um aumento significativo no diâmetro folicular. Entretanto, contrário ao observado no meio controle, a MET revelou que os folículos cultivados nesses tratamentos apresentavam sinais evidentes de atresia. Em conclusão, esse estudo demonstrou que a BMP-6 afeta negativamente a sobrevivência e a ultra-estrutura de folículos primordiais caprinos. This study investigated the effects of bone morphogenetic protein 6 (BMP-6) on in vitro primordial follicle development in goats. Samples of goat ovarian cortex were cultured in vitro for 1 or 7 days in Minimum Essential Medium (control medium) supplemented with different concentrations of BMP-6. Follicle survival, activation and growth were evaluated through histology and transmission electron microscopy (TEM). After 7 days of culture, histological analysis demonstrated that BMP-6 enhanced the percentages of atretic primordial follicles when compared to fresh control (day 0). Nevertheless, BMP-6 increased follicular and oocyte diameter during both culture periods. As the culture period progressed from day 1 to day 7, a significant increase in follicle diameter was observed with 1 or 50ng/ml BMP-6. However, on the contrary to that observed with the control medium TEM revealed that follicles cultured for up to 7 days with 1 or 50ng/ml BMP-6 had evident signs of atresia. In conclusion, this study demonstrated that BMP-6 negatively affects the survival and ultrastructure of goat primordial follicles.

Bone morphogenetic proteins (BMP) 2, 4, 6 and 7 affect ovarian follicular development through regulation of follicle-stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHR) expression in goat granulosa cells

“…It was reported that BMP6 increased goat follicular and oocyte diameter but negatively affected the survival and ultrastructure of goat primordial follicles (Araújo et al, 2010). BMP7 reduced the number of primordial follicles, but the number of primary, preantral and antral follicles increased in rat ovary (Shimasaki et al, 1999).…”

Bone Morphogenetic Protein‐6 (BMP‐6) Stimulates the Antrum Formation by the Regulation of its Signalling Pathway in Caprine Pre‐antral Follicles Cultured In Vitro

“…In a recent study, we showed the deleterious effect of BMP‐6 on the in vitro culture of pre‐antral follicles enclosed in caprine ovarian cortex ( in situ culture system; Araújo et al. ). Histological and ultrastructural analyses revealed that BMP‐6, even at low concentrations (1 ng/ml), induced atresia in primordial follicles (Araújo et al.…”

“…The concentrations of BMP‐6 (Sigma Chemical Co.) were chosen based on previous studies performed in our laboratory (Araújo et al. ). The culture was replicated five times, and at least 40 follicles were used per treatment.…”

“…Indeed, we reported the first use of BMP‐6 in the culture medium of primordial follicles (Araújo et al. ), in which the follicles were cultured enclosed in the caprine ovarian cortex, that is in situ .…”

Influence of caprine arthritis encephalitis on expression of ovulation related genes and activation of primordial follicles cultured in presence of phytohemagglutinin, epidermal growth factor or both

“…Thus, it is very important to evaluate if CAEV influences early folliculogenesis in vitro. Several studies have shown that culture of primordial follicle is an alternative to study follicular development and atresia in vitro (Markström et al, 2002;Silva et al, 2004a;Hutt et al, 2006;Celestino et al, 2009;Araújo et al, 2010;Kim, 2012;Kalich-Philosoph et al, 2013;Portela et al, 2014;Ribeiro et al, 2014). The effects of several growth factors, such as epidermal growth factor (EGF) (Silva et al, 2004a) on activation and atresia of goat primordial follicles in vitro have been tested, but substances that are not produced by the ovaries, such as phytohemagglutinin (PHA) were still not evaluated.…”