Luteogenesis in cyclic ewes: echotextural, histological, and functional correlates.
To date, it has not been possible to detect corpus luteum (CL) by ultrasonography, immediately following ovulation, in the ewe. Early CL detection is essential to be able to relate luteal outcome to the developmental pattern of the ovulated follicle and to confirm ovulation. Image analysis of the CL may be useful in providing a noninvasive picture of CL differentiation and function. The present study was designed to use high-resolution ultrasonography to monitor and to correlate the echotextural, histological, and functional attributes of the developing ovine CL from Days 1 to 3 after ovulation. Ten ewes underwent twice-daily transrectal ultrasonography and blood sampling from the day of synchronized estrus. Ewes were ovariectomized at 12-24, 36-48, and 60-72 h after ovulation. Ovaries collected were scanned in a water bath before processing for histology. Ultrasonographic images of CL were analyzed for echotexture. Histological sections were analyzed for the percentage area of the CL occupied by blood clot or luteal tissue. Serum samples were analyzed for progesterone concentration. Numerical pixel value, heterogeneity, and percentage of the CL occupied by blood clot declined (P<0.05) from 12-24 to 60-72 h after ovulation. Luteal area and serum progesterone concentration increased (P<0.05) from 12-24 to 60-72 h. The results indicated that it was possible to visualize developing CL as early as 12-24 h after ovulation in the ewe. Echotexture of the CL was closely associated with its morphological and functional characteristics; image analysis holds promise for noninvasive monitoring of CL differentiation and growth.
Duggavathi
R
R
Department of Veterinary Biomedical Sciences, WCVM, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5B4.
Bartlewski
P M
PM
Pierson
R A
RA
Rawlings
N C
NC
D000818:Animals; D001777:Blood Coagulation / Q000502:physiology; D003338:Corpus Luteum / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000502:physiology*; D030762:Estrous Cycle / Q000502:physiology*; D005260:Female; D006728:Hormones / Q000097:blood / Q000502:physiology; D007090:Image Interpretation, Computer-Assisted; D006080:Ovarian Follicle / Q000502:physiology; D010053:Ovary / Q000000981:diagnostic imaging / Q000502:physiology; D010060:Ovulation / Q000502:physiology; D011374:Progesterone / Q000097:blood; D012756:Sheep; D014463:Ultrasonography
D006728:Hormones; D011374:Progesterone