The Effects Of Glucocorticoid On The Formation Of Primordial Follicle Pool And Early Ovarian Follicular Development

Objective: To investigate the effects of glucocorticoid on the formation of primordialfollicle pool and early ovarian follicular development in neonatal mice.Methods: A total of24C57BL/6mice were caged together with male and femaleratio of1：3, and the neonatal female mice were divided into four groups．Each groupcontains mice treated with dexamethasone and mice with NS respectively.Group one: DEX(d1,3,5) represent the neonatal mice administered a subcutaneousinjection of10mg/kg of DEX on D1、D3and D5; CON(d1,3,5) represent the controlmice administered a subcutaneous injection of10mg/kg of NS on D1、D3and D5.Group two: DEX (d1) represent the neonatal mice administered a subcutaneousinjection of10mg/kg of DEX on D1; CON (d1) represent the control miceadministered a subcutaneous injection of10mg/kg of NS on D1.Group three: DEX (d3) represent the neonatal mice administered a subcutaneousinjection of10mg/kg of DEX on D3; CON (d3) represent the control miceadministered a subcutaneous injection of10mg/kg of NS on D3.Group four: DEX (d5) represent the neonatal mice administered a subcutaneousinjection of10mg/kg of DEX on D5; CON (d5) represent the control miceadministered a subcutaneous injection of10mg/kg of NS on D5.Left ovaries from7-day-old female pups were stereologically analyzed. The numberof primordial and primary follicles and the number of secondary follicles wasdetermined by exact counts.Results: In group one，compared with group CON(d1,3,5), the number and the ratioof primordial follicles from group DEX(d1,3,5) decreased remarkably, while thenumber and the ratio of primary and secondary follicles from group DEX(d1,3,5)increased.(P<0.05).In group two，compared with group CON(d1), the number and the ratio of primordialfollicles from group DEX(d1) decreased remarkably (P<0.05), while the ratio ofprimary follicles from group DEX(d1) increased remarkably (P<0.05). But as tosecondary follicles, there was no significant difference between group CON (d1) and DEX (d1).(P>0.05)．In group three，as to the number and the ratio of primordial follicles and primary andsecondary follicles, there were no significant differences between CON(d3) andDEX(d3).(P>0.05)．In group four，there were no significant differences between CON(d5) and DEX(d5)in the ratio of primordial follicles and primary and secondary follicles, also.(P>0.05)．Conclusion：The early use of glucocorticoid especially at D1after birth（the stage ofcyst breakdown) may decrease the number of primordial follicles, thus downsize thepool of primordial follicles in neonatal mice. When the mice were treated withglucocorticoid more than one time, such as at D1、D3and D5after birth，except thatthe primordial follicles decreased, the ovarian follicular development of mice mayspeed up as well，thus may be harmful to the reproductive lifespan of ovary.