Effect of insulin on oogenesis from mouse fetal germ cells in a serum-free 3D culture system.
Continuous exposure of oocytes to elevated concentrations of insulin compromises embryonic developmental competence. However, the effects of insulin on oogenesis from fetal germ cells are unknown. The objective of this study was to assess the effect of continuous insulin exposure, with or without FSH, on oogenesis and follicular development. A simple and efficient method was established that could be used to obtain oocytes from pre-meiotic germ cells in 12.5days post-coitum (dpc) fetal mouse ovaries using a three-dimensional culture system with serum-free medium. Mouse 12.5dpc fetal ovaries were cultured for 14days with or without insulin/FSH. Low (0.2-1microg/ml) or high (5-20microg/ml) doses of insulin retarded oocyte growth in vitro. Insulin at 5microg/ml led to significant oocyte growth retardation (P<0.05), while FSH alleviated the deleterious effect of insulin. Most importantly, the proportion of secondary follicles at 12days post-culture in the presence of insulin was reduced significantly compared with controls (P<0.05). Expression levels of genes specific for ovarian cells, e.g. Cx37, Cx43, Scp3, Bax and FSHR, were significantly reduced when exposed to insulin during oogenesis (P<0.05). The data suggest that insulin has a profound detrimental effect on oogenesis and folliculogenesis in vitro.
Laboratory of Germ Cell Biology, College of Animal Science and Technology, Qingdao Agricultural University, Qingdao 266109, China.
L L
LL
Sun
Z Y
ZY
Sun
P
P
Zhang
X W
XW
Zhai
J
J
Tang
Q J
QJ
Pan
Q H
QH
Shi
W
W
Shen
D000818:Animals; D018929:Cell Culture Techniques / Q000379:methods; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D049469:Meiotic Prophase I / Q000187:drug effects; D051379:Mice; D008815:Mice, Inbred Strains; D009865:Oocytes / Q000187:drug effects* / Q000502:physiology; D009866:Oogenesis / Q000187:drug effects*; D010063:Ovum / Q000166:cytology / Q000187:drug effects*; D011247:Pregnancy
D007004:Hypoglycemic Agents; D007328:Insulin; D005640:Follicle Stimulating Hormone