June 2013 (No. 2)
Populations of follicles in F344/N rats during aging
Kazutoshi Nishijima a,*, Shin Tanaka b, Shinsuke H. Sakamoto c, Sachi Kuwahara d, Tamio Ohno e, Shuji Kitajima a
a Division of Biological Resources and Development, Analysis Research Center for Experimental Sciences, Saga University, Saga, Japan;
b Formerly Animal Facility for Aging Research, National Center for Geriatrics and Gerontology (NCGG), Obu, Japan;
c Department of Bio-resources, Division of Biotechnology, Frontier Science Research Center, University of Miyazaki, Miyazaki, Japan;
d Department of Anatomy, Hyogo Collage of Medicine, Nishinomiya, Japan;
e Division of Experimental Animals, Center for Promotion of Medical Research and Education, Graduate School of Nagoya University, Nagoya, Japan
Follicular populations were investigated in female F344/N rats to better understand the aging process of the rat ovary. Ovaries dissected at various ages (spanning 1–36 months old) were submitted for histological examination. The totalnumber of primordial, growing (primary and secondary), tertiary, and atretic follicles as well as corpora lutea (CL) were counted in hematoxylin–eosin- and azocarmine–aniline-blue-stained ovarian sections. The number of healthy follicles including primordial, growing and tertiary follicles decreased rapidly between the first and third months and gradually thereafter. CL were found in 3-month-old rats, and their number remained unchanged until 18 months of age, at which point it decreased. The number of atretic follicles startedtoincrease in rats older than18months,whichcorresponded to the cessation of estrous cyclicity. Several healthy follicles and CL were observed even in 36-month-old rats.
Reproductive Biology 2013 13 2: 145–149.
* Corresponding author: Division of Biological Resources and Development, Analysis Research Center for Experimental Sciences, Saga University, 5-1-1 Nabeshima, Saga 849-8501, Japan; e-mail address: email@example.com