440 EVALUATION OF FOLLICULAR GROWTH AFTER EXOGENOUS STIMULATION IN MICE USING ULTRASOUND BIOMICROSCOPY
P. H. A. Campos-Junior A , C. S. Silva C , J. G. V. Grázia D , R. I. T. P. Batista A , V. V. Maffili C , R. R. Santos C and J. H. M. Viana AA Embrapa Gado de Leite, Juiz de Fora, Minas Gerais, Brazil;
B CES/JF, Juiz de Fora, Minas Gerais, Brazil;
C FIOCRUZ, Salvador, Bahia, Brazil;
D UFJF, Juiz de Fora, Minas Gerais, Brazil
Reproduction, Fertility and Development 22(1) 377-377 https://doi.org/10.1071/RDv22n1Ab440
Published: 8 December 2009
Abstract
Real-time follicular dynamics studies have often been restricted to large animals because of the resolution of ultrasound equipment available. The recent advances in image technology, including significant gains in spatial resolution, allowed these evaluations to be performed in small rodents, which are important models to understand folliculogenesis. The aim of this study was to evaluate exogenous stimulated follicular growth in mice using a high resolution ultrasound. Female mice (n = 15) received a 5 IU i.p. injection of eCG (Vetecor®, Calier) and 48 h later a 5 IU injection of hCG (Novormon®, Schering-Plough), and were mated thereafter. In experiment 1, animals (n = 7) were anesthetized with ketamin/xilazin solution and evaluated at 3, 9, 15, 21, 27, 33, 45, and 51 h after eCG injection. The ovaries were identified with ultrasound biomicroscopy (UBM, Vevo 660®, Visual Sonics, Toronto, ON, Canada) coupled with real-time micro-visualization probe (RMV 707b), and the follicular population was measured, quantified, and classified into small follicles (≤449 μm) and large follicles (≥450 μm). The number of small follicles decreased (P < 0.05) from 30.44 ± 15.91 to 14.79 ± 7.23, and the number of large follicles (≥450 μm) increased from 0.36 ± 0.74 to 4.21 ± 4.25. For both size classes, however, statistical differences only occurred at 45 h after eCG; that is, close to the moment of hCG injection. In experiment 2, animals (n = 8) were evaluated every 2 h beginning 4.5 h after hCG to check for ovulations. The largest follicles achieved a mean maximum size of 596.7 ± 106.0 μm, 5.8 ± 2.3 h after hCG application. In 5 animals, large follicles were observed at 2 distinct moments, 5.0 ± 1.2 h and 10.4 ± 1.0 h after hCG, respectively. Results suggest that the later stages of follicular growth in mice are only achieved a few hours before ovulation, and that ovulations induced by hCG are not synchronized.
Financial suport: Fapemig, CBTC São Rafael, CNPq.
