Effect of repeated gonadotropin stimulation on ovarian reserves and proliferation of ovarian surface epithelium in mice

Abstract

This study aimed to evaluate the effect of repeated ovarian stimulation (OS) on the ovarian follicular population and morphology in female mice and its influence on the embryo’s developmental ability, and the profile of the ovarian surface epithelium (OSE). A total of 75 mice were enrolled in this experiment and randomly assigned into three groups: repeated ovarian stimulated group [n=25; receiving 5 IU pregnant mare serum gonadotrophin (PMSG) and human chorionic gonadotropin (hCG) at 6 day intervals for 5 cycles]; single ovarian stimulated group (n=25; receiving 5 IU PMSG and hCG for 1 cycle), and control group (n=25; without additional treatment). The follicle number at various stages and the morphologies were recorded respectively in the three groups. The harvested oocytes or embryos, cleavage rate, good quality embryo rate, and blastocyst production rate were counted and calculated, and the proliferations of ovarian surface epithelium were evaluated respectively. In the three groups, the single ovarian stimulation treatment significantly increased the mean number of ovarian oocytes or embryos (39.25±10.77 one-cell embryos/female); on the other hand, repeated gonadotropin stimulation obtained the lowest mean number (5.15± 2.81 eggs/female, P<0.01). Repeated ovarian stimulation also tended to decrease normal follicles of primary follicles (66.67%) and secondary follicles (72.86%), and got the lowest cleavage rate (67.47%), lowest good quality embryo rate (2.41%), and lowest blastocyst production rate (0). The OSE cells adjacent to the antral follicles and corpus luteum (CL) in the repeated ovarian stimulated group (81.8%) had a significantly higher proliferation rate than the other groups. The proliferation rate of the OSE in the single ovarian stimulated group (56.4%) was significantly higher than that in the control group (37.5%) (P<0.01). In conclusion, single ovarian stimulation may produce more oocytes/embryos. However, repeated gonadotropin stimulation may have a negative effect on the ovarian follicular quality, the number of mature retrieved oocytes, and the embryo quality, even increasing the chance of ovarian cancer.

Key words： gonadotropin-releasing hormone; ovarian reserve; embryo developmental ability; ovarian surface epithelium

Acknowledgements

This work was supported by the Special Funds for State Key Development Program for Basic Research of China (973 Program) (No. 2007CB948104 ).

References

1 FowlerR E,EdwardsR G.Induction of superovulation and pregnancy in mature mice by gonadotrophins. J Endocrinol, 1957, 15(4): 374-384

2 ErtzeidG,StorengR.The impact of ovarian stimulation on implantation and fetal development in mice. Hum Reprod, 2001, 16(2): 221-225

3 HashimotoS,KuramochiT,AoyagiK,TakahashiR,UedaM,HiraoM,KameiM,KitadaK,HirasawaK.Refined porcine follicle stimulating hormone promotes the responsiveness of rabbits to multiple-ovulation treatment. Exp Anim, 2004, 53(4): 395-397

4 KelleyR L,KindK L,LaneM,RobkerR L,ThompsonJ G,EdwardsL J.Recombinant human follicle-stimulating hormone alters maternal ovarian hormone concentrations and the uterus and perturbs fetal development in mice. Am J Physiol Endocrinol Metab, 2006, 291(4): E761-770

5 De FeuM A,PattonJ,EvansA C,LonerganP,ButlerS T.The effect of strain of Holstein-Friesian cow on size of ovarian structures, periovulatory circulating steroid concentrations, and embryo quality following superovulation. Theriogenology, 2008, 70(7): 1101-1110

6 SwansonW F,RothT L,GrahamK,HorohovD W,GodkeR A.Kinetics of the humoral immune response to multiple treatments with exogenous gonadotropins and relation to ovarian responsiveness in domestic cats. Am J Vet Res, 1996, 57(3): 302-307

7 CombellesC M,AlbertiniD F.Assessment of oocyte quality following repeated gonadotropin stimulation in the mouse.Biol Reprod,2003,68(3):812-821

8 ErtzeidG,StorengR.Adverse effects of gonadotrophin treatment on pre- and postimplantation development in mice.J Reprod Fertil,1992,96: 649-655

9 van der AuweraI,D'HoogheT.Superovulation of female mice delays embryonic and fetal development. Hum Reprod,2001,16(6):1237-1243

10 GodwinA K,TestaJ R,HandelL M,LiuZ,VanderveerL A,TraceyP A,HamiltonT C. Spontaneous transformation of rat ovarian surface epithelial cells: association with cytogenetic changes and implications of repeated ovulation in the etiology of ovarian cancer.J Natl Cancer Inst,1992, 84(8):592-601

11 BoseC K.Follicle stimulating hormone receptor in ovarian surface epithelium and epithelial ovarian cancer.Oncol Res,2008,17(5): 231-238

12 KatabuchiH,OkamuraH.Cell biology of human ovarian surface epithelial cells and ovarian carcinogenesis.Med Electron Microsc, 2003,36(2):74-86

13 MurphyB D,MartinukS D.Equine chorionic gonadotropin.Endocr Rev,1991,12(1): 27-44

14 GougeonA.Dynamics of follicular growth in the human: a model from preliminary results. Hum Reprod,1986,1(2): 81-87

15 ClearyM,SnowM,ParisM,ShawJ,CoxS L,JenkinG.Cryopreservation of mouse ovarian tissue following prolonged exposure to an ischemic environment.Cryobiology,2001,42(2): 121-133

16 LucciC M,KacinskisM A,RumpfR,BáoS N.Effects of lowered temperatures and media on short-term preservation of zebu (Bos indicus) preantral ovarian follicles.Theriogenology,2004, 61(2,3): 461-472

17 CombellesC M,AlbertiniD F.Microtubule patterning during meiotic maturation in mouse oocytes is determined by cell cycle-specific sorting and redistribution of gamma-tubulin. Dev Biol, 2001, 239(2): 281-294

18 BurdetteJ E,KurleyS J,KilenS M,MayoK E,WoodruffT K.Gonadotropin-induced superovulation drives ovarian surface epithelia proliferation in CD1 mice. Endocrinology, 2006, 147(5): 2338-2345

19 YangS,HeX,HildebrandtT B,JewgenowK,GoeritzF,TangX,ZhouQ,JiW.Effects of rhFSH dose on ovarian follicular response, oocyte recovery and embryo development in rhesus monkeys.Theriogenology, 2007, 67(6): 1194-1201

20 LeeS T,KimT M,ChoM Y,MoonS Y,HanJ Y,LimJ M.Development of a hamster superovulation program and adverse effects of gonadotropins on microfilament formation during oocyte development.Fertil Steril, 2005, Suppl 1:1264-1274

21 LeeS T,HanH J,OhS J,LeeE J,HanJ Y,LimJ M.Influence of ovarian hyperstimulation and ovulation induction on the cytoskeletal dynamics and developmental competence of oocytes. Mol Reprod Dev, 2006, 73(8): 1022-1033

22 PalL,JindalS,WittB R,SantoroN.Less is more: increased gonadotropin use for ovarian stimulation adversely influences clinical pregnancy and live birth after in vitro fertilization.Fertil Steril,2008,89(6): 1694-1701

23 SchipperI,HopW C,FauserB C.The follicle-stimulating hormone (FSH) threshold/window concept examined by different interventions with exogenous FSH during the follicular phase of the normal menstrual cycle: duration, rather than magnitude, of FSH increase affects follicle development.J Clin Endocrinol Metab, 1998, 83(4): 1292-1298

24 ChaoH T,LeeS Y,LeeH M,LiaoT L,WeiY H,KaoS H.Repeated ovarian stimulations induce oxidative damage and mitochondrial DNA mutations in mouse ovaries. Ann N Y Acad Sci, 2005,1042: 148-156

25 IwataN,InazuN,EndoT,SatohT.Gonadotropin-induced ovarian carbonyl reductase in mice and hamsters: comparison with carbonyl reductase in rats.Life Sci,1993,53(23): 1729-1733

26 BlondinP,CoenenK,GuilbaultL A,SirardM A.Superovulation can reduce the developmental competence of bovine embryos.Theriogenology,1996 ,46(7):1191-1203

27 WongA S,AuerspergN.Normal ovarian surface epithelium.Cancer Treat Res,2002,107: 161-183

28 AuerspergN,EdelsonM I,MokS C,JohnsonS W,HamiltonT C.The biology of ovarian cancer.Semin Oncol,1998,25(3):281-304

29 MurdochW J,TownsendR S,McDonnelA C.Ovulation-induced DNA damage in ovarian surface epithelial cells of ewes: prospective regulatory mechanisms of repair/survival and apoptosis.Biol Reprod,2001,65(5):1417-1424

30 MurdochW J.Metaplastic potential of p53 down-regulation in ovarian surface epithelial cells affected by ovulation.Cancer Lett,2003,191(1): 75-81

31 TestaJ R,GettsL A,SalazarH,LiuZ,HandelL M,GodwinA K,HamiltonT C. Spontaneous transformation of rat ovarian surface epithelial cells results in well to poorly differentiated tumors with a parallel range of cytogenetic complexity.Cancer Res,1994, 54(10): 2778-2784

32 TanO L,FlemingJ S.Proliferating cell nuclear antigen immunoreactivity in the ovarian surface epithelium of mice of varying ages and total lifetime ovulation number following ovulation.Biol Reprod,2004,71(5):1501-1507