Quanwei Wei1, Fangxiong Shi1, Jianwen He1, Chong Xie1, Ke Xu1, Wei Zhang1, Siyu Sun1, Jaafar Fedail1, Gen Watanabe2,3, Kazuyoshi Taya2,3. 1. College of Animal Science and Technology Nanjing Agricultural University Nanjing People's Republic of China. 2. Laboratory of Veterinary Physiology, Department of Veterinary Medicine, Faculty of Agriculture Tokyo University of Agriculture and Technology Tokyo Japan. 3. Department of Basic Veterinary Science, The United Graduate School of Veterinary Sciences Gifu University Gifu Japan.
Abstract
PURPOSE: The study was aimed to examine the effects of exogenous 17β-estradiol (E2) on oocyte nest breakdown and follicular growth in the ovary of neonatal and immature mice. METHODS: The effect of E2 on primordial follicle formation and differentiation were examined by treating neonatal mice with E2 in mineral oil at a dose of 10 mg/kg by sc injection each day from postnatal days 1 (PND1) to 10 (PND10). This investigation was conducted by using histological observation and immunohistochemical staining of proliferating cell nuclear antigen (PCNA); the numbers of follicles at each stage were examined to assess the follicular development. RESULTS: The results indicated that such dose of E2 inhibited oocyte nest breakdown from PND1 to PND10 significantly and enhanced the oocyte staining intensity of PCNA in the ovary by PND3, 5 and 10. PCNA staining was mainly detected on growing follicles (stages later than primary follicle). Our results also revealed that E2 decreased the size of the reproductive tract at PD10. CONCLUSIONS: This dose of E2 treatment inhibits oocyte nest breakdown and primordial follicle assembly, and causes follicle losses after PND5. Effects of exogenous E2 on follicular development in the neonatal and immature mouse may through a PCNA-dependent pathway.
PURPOSE: The study was aimed to examine the effects of exogenous 17β-estradiol (E2) on oocyte nest breakdown and follicular growth in the ovary of neonatal and immature mice. METHODS: The effect of E2 on primordial follicle formation and differentiation were examined by treating neonatal mice with E2 in mineral oil at a dose of 10 mg/kg by sc injection each day from postnatal days 1 (PND1) to 10 (PND10). This investigation was conducted by using histological observation and immunohistochemical staining of proliferating cell nuclear antigen (PCNA); the numbers of follicles at each stage were examined to assess the follicular development. RESULTS: The results indicated that such dose of E2 inhibited oocyte nest breakdown from PND1 to PND10 significantly and enhanced the oocyte staining intensity of PCNA in the ovary by PND3, 5 and 10. PCNA staining was mainly detected on growing follicles (stages later than primary follicle). Our results also revealed that E2 decreased the size of the reproductive tract at PD10. CONCLUSIONS: This dose of E2 treatment inhibits oocyte nest breakdown and primordial follicle assembly, and causes follicle losses after PND5. Effects of exogenous E2 on follicular development in the neonatal and immature mouse may through a PCNA-dependent pathway.
Authors: Karl R Hansen; Nicholas S Knowlton; Angela C Thyer; Jay S Charleston; Michael R Soules; Nancy A Klein Journal: Hum Reprod Date: 2008-01-11 Impact factor: 6.918