Abstract

BACKGROUND AND OBJECTIVE: In vitro maturation (IVM) of oocyte is a promising teclmique to reduce the costs and avert the side-effects of gonadotropin stimulation for in vitro fertilization (IVF). In vitro follicular culture systems at various developmental stages allow the identification of these factors and the understanding of their mechanisms of action. The aim of this study was to evaluate the influence of FSH hormone on preantral follicular growth and differentiation during in vitro follicular culture using the rodent (mouse) model. METHODS: This semi experimental study was performed on 30 numbers of six to eight week Syrian mice. For preparation of preantral follicular, the ovaries were removed aseptically and placed in petri dishes filled at room temperature with the basal medium. Special quantities of FSH (5, 20, 40, 60, 100,140, 180 and 220M IU/l of FSH) was added to the culture mediums (containing 25-30 follicles) during separate experiments. Effect of gonadotrophin (FSH) was evaluated on the growth and viability of the follicles and oocyte maturation afier 6 days. FINDINGS: During present study, 100 mIU/ml FSH showed highly significant effect on follicle and oocyte growth as follicle survival rate also increased (91) as compared to the follicles survived when the culture was grown without this gonadotrophin (28). The survival rate of the follicles increased (30) up to day 6 as compared to days 2 (17), 4 (24) and 8 (29), p<0.05. Oocyte maturation (61) and germinal vesicle breakdown rates (81) also showed a significant increase. CONCLUSION: The results of this study show that the follicular growth rate was increasing linearly up to the day-6 but after this it became almost constant. A gradual constancy of these rates was noticed during the last 2 days of culture in TCM199 medium, implying that these culture conditions were not enough to sustain a long-term follicular culture and follicles needed some growth enhancers.