The effects of small litter rearing on ovarian function at puberty and adulthood in the rat.
Rearing rats in small litters lead to obesity and reproductive dysfunction. We investigated the effects of rearing female rats in small litters on various reproductive parameters during puberty and into adulthood, and examined the possible involvement of local ovarian sympathetic nerve activity. The litter size was adjusted on postnatal day one to four pups per dam for the small litters and 12 pups per dam for the normal litters. Vaginal opening was recorded, and estrous cyclicity was monitored daily immediately post puberty for 14 days and again at 8-9 weeks of age. At the time of puberty and 10 weeks of age, the ovaries were collected. The number of different types of follicles was counted and the thickness of the theca interna of the largest antral follicles was measured. Ovarian sympathetic nerve activity was assessed immunohistochemically by measuring levels of ovarian nerve growth factor receptor (p75NGFR) and tyrosine hydroxylase (TH). In rats reared in small litters, there was a significant advancement of puberty and disruption of estrous cyclicity immediately post puberty. The number of antral follicles increased in the small litter reared rats at puberty compared with their controls. The thickness of the theca interna increased and the expression profiles of ovarian p75NGFR and TH increased in small litter reared rats at puberty, but this did not persist into adulthood. These data suggest that rearing rats in small litters lead to irregular reproductive cycles, which might involve increased local ovarian sympathetic nerve activity.
Department of Gynecology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, People's Republic of China.
Xue-Qing
XQ
Wu
Department of Gynecology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, People's Republic of China; Division of Women's Health, Faculty of Life Sciences and Medicine, King's College London, Guy's Campus, 2.92W, Hodgkin Building, London SE1 1UL, UK.
Xiao-Feng
XF
Li
Department of Gynecology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, People's Republic of China.
Wei-Ting
WT
Xia
Department of Gynecology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, People's Republic of China.
Bilu
B
Ye
Department of Gynecology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, People's Republic of China; Division of Women's Health, Faculty of Life Sciences and Medicine, King's College London, Guy's Campus, 2.92W, Hodgkin Building, London SE1 1UL, UK. Electronic address: kevin.o'byrne@kcl.ac.uk.
Kevin T
KT
O'Byrne
D000818:Animals; D030762:Estrous Cycle / Q000502:physiology*; D005260:Female; D008098:Litter Size; D009419:Nerve Tissue Proteins; D010053:Ovary / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017978:Receptors, Growth Factor; D017475:Receptors, Nerve Growth Factor / Q000378:metabolism; D012741:Sexual Maturation / Q000502:physiology*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D009419:Nerve Tissue Proteins; D017978:Receptors, Growth Factor; D017475:Receptors, Nerve Growth Factor; C068313:Ngfr protein, rat; D014446:Tyrosine 3-Monooxygenase
Follicle; Obesity; Ovary; Puberty; Sympathetic