title: Histological characteristics of the regression of corpora lutea in wistar hannover rats: the comparisons with sprague-dawley rats.
abstract: We examined the ovaries of 44 Wistar Hannover (RccHan(TM):WIST) (WH) and 30 Sprague-Dawley (SD) rats at 32-weeks of age to determine whether the ovarian structure and formation/regression of the corpora lutea (CLs) differ between the two strains. The average ovary weight was higher in WH rats. The average number of all CLs, including currently formed and previously formed CLs, was higher in WH rats in all cycles; however, no appreciable difference was detected in the number of newly or currently formed CLs between the two strains. CLs regression characterized by degeneration and necrosis of luteal cells began to appear in diestrus in both strains; however, the distribution of degenerated/necrotic cells in CLs differed. Necrotic cells were scattered in SD rats but were focally observed in the center of the CL in WH rats. The reduction in size of previously formed CLs accompanied by regression started about 2 or more stages later in WH rats than in those of SD rats. In conclusion, the higher number of CLs in WH rats is considered to be due to slow CL regression compared with in SD rats.
authors.affiliation: Pathology Department, Kashima Laboratory, Nonclinical Research Center, LSI Medience Corporation, 14-1 Sunayama, Kamisu, Ibaraki 314-0255, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Sato
authors.affiliation: Pathology Department, Kashima Laboratory, Nonclinical Research Center, LSI Medience Corporation, 14-1 Sunayama, Kamisu, Ibaraki 314-0255, Japan.
authors.forename: Satomi
authors.initials: S
authors.lastname: Hashimoto
authors.affiliation: Pathology Department, Kashima Laboratory, Nonclinical Research Center, LSI Medience Corporation, 14-1 Sunayama, Kamisu, Ibaraki 314-0255, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Doi
authors.affiliation: Pathology Department, Kashima Laboratory, Nonclinical Research Center, LSI Medience Corporation, 14-1 Sunayama, Kamisu, Ibaraki 314-0255, Japan.
authors.forename: Naoaki
authors.initials: N
authors.lastname: Yamada
authors.affiliation: Pathology Department, Kashima Laboratory, Nonclinical Research Center, LSI Medience Corporation, 14-1 Sunayama, Kamisu, Ibaraki 314-0255, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Tsuchitani
keywords: Sprague-Dawley; Wistar Hannover; corpora lutea; estrous cycle; ovary; rat