Resumo
The present study aims to investigate the influence of two concentrations of ascorbic acid on the survival, growth , antral formation and m RNA expression of the matrix metalloproteinases - 9 (MMP - 9) and their tissue inhibitor - 2 (TIMP - 2) on caprine preantral follicles during long - term in vitro culture. Isolated preantral follicles were individ ually cultured without or with ascorbic acid at 50 μ g/ml (AA50) or 100 μ g/ml (AA100) during 18 days. The parameters evaluated were follicular viability, growth, antrum formation and extruded oocytes. The genes MMP - 9 and TIMP - 2 were quantified by real - time polymer ase chain reaction (qPCR) after 18 days of culture in the control medium (MEM + ) or ascorbic acid (50 or 100 μ g/ml) and in fresh control (non cultured) . At the end of culture, AA50 significantly increased the percentage of viable follicles compared w ith other treatments . Moreover, mean daily increase in follicular diameter (μm/day) was significantly higher in the presence of both concentrations of ascorbic acid than in MEM + alone. Higher rates of antral formation and lower percentages of extruded oocy tes were observed in medium containing AA50 compared with control medium. Real Time RT - PCR assays showed that AA50 increase s MMP - 9 expression significantly compared with fresh control and MEM + alone. In conclusion, ascorbic acid at 50 μ g/ml was very import ant for the maintenance of caprine preantral follicle viability and development after in vitro culture and influences in vitro the enzymes involved with basement membrane remodeling.
Assuntos
Animais , Folículo Ovariano/anatomia & histologia , Membrana Basal/anatomia & histologia , Oócitos/citologia , Ácido Ascórbico/química , Cabras/fisiologiaResumo
The present study aims to investigate the influence of two concentrations of ascorbic acid on the survival, growth , antral formation and m RNA expression of the matrix metalloproteinases - 9 (MMP - 9) and their tissue inhibitor - 2 (TIMP - 2) on caprine preantral follicles during long - term in vitro culture. Isolated preantral follicles were individ ually cultured without or with ascorbic acid at 50 μ g/ml (AA50) or 100 μ g/ml (AA100) during 18 days. The parameters evaluated were follicular viability, growth, antrum formation and extruded oocytes. The genes MMP - 9 and TIMP - 2 were quantified by real - time polymer ase chain reaction (qPCR) after 18 days of culture in the control medium (MEM + ) or ascorbic acid (50 or 100 μ g/ml) and in fresh control (non cultured) . At the end of culture, AA50 significantly increased the percentage of viable follicles compared w ith other treatments . Moreover, mean daily increase in follicular diameter (μm/day) was significantly higher in the presence of both concentrations of ascorbic acid than in MEM + alone. Higher rates of antral formation and lower percentages of extruded oocy tes were observed in medium containing AA50 compared with control medium. Real Time RT - PCR assays showed that AA50 increase s MMP - 9 expression significantly compared with fresh control and MEM + alone. In conclusion, ascorbic acid at 50 μ g/ml was very import ant for the maintenance of caprine preantral follicle viability and development after in vitro culture and influences in vitro the enzymes involved with basement membrane remodeling.(AU)