PARENT SESSION

(121) TUMOR NECROSIS FACTOR ALPHA (TNF) REGULATES PRIMORDIAL FOLLICLE RECRUITMENT IN THE MOUSE OVARY THROUGH ITS TYPE II RECEPTOR (TNFR2).

Greenfeld, Chuck¹, Roby, Kathy², Babus, Janice¹, Terranova, Paul², Flaws, Jodi¹, ¹ University of Maryland Medical School, Baltimore, MD² University of Kansas, Kansas City, KS

ABSTRACT- Female mammals are born with a finite pool of primordial follicles. These follicles are depleted through atresia or ovulation. Once the follicle pool has been depleted, fertility ceases. Relatively little is known regarding the regulation of follicle recruitment and exit from the primordial pool. Tumor necrosis factor alpha (TNF) and its two receptors (TNFR1 and TNFR2) are expressed in the neonatal mouse ovary at the time of follicle formation, and their expression continues in the adult ovary. This expression pattern suggests that TNF may play a role in primordial follicle dynamics. Therefore, the objective of this study was to examine whether TNF and its receptors participate in the regulation of primordial follicle recruitment. Ovaries were collected from mouse pups (day of birth) and cultured in supplemented Waymouth's medium with 0-50 ng/ml TNF. After 3 days in culture, ovaries were subjected to histological evaluation of the numbers of naked oocytes (i.e., those oocytes not yet incorporated into follicles), primordial follicles, and primary follicles. Further, ovaries were collected from TNFR1 deficient (TNFR1-/-), TNFR2 deficient (TNFR2-/-), and wild type (WT) females on postnatal day (PN) 7, and subjected to histological evaluation of follicle numbers. The results show that TNF (50 ng/ml) reduced the number of naked oocytes and primary follicles compared to non-treated controls (primary follicles: control=119.1+11.9; TNF=53.4+10.4; p<0.005). Deletion of TNFR1 had no effect on follicle numbers compared to WT ovaries at PN7 (n=5-7; p=0.2). In contrast, deletion of TNFR2 resulted in significantly more growing follicles compared to WT ovaries at PN7 (primary follicles: WT=388.3+21.3; TNFR2-/-=762.7+21.1; p<0.005; preantral follicles: WT=0.0+0.0; TNFR2-/-=7.9+1.6; p<0.005; n=4-9) and at PN23 (primary follicles: WT=72.4+3.5; TNFR2-/-=96.3+12.2; p<0.05; preantral follicles: WT=84.2+1.9; TNFR2-/-=143.0+10.7; p<0.05; n=3-5). Treatment of TNFR2-/- neonatal ovaries with TNF (50 ng/ml) had no effect on primary follicle numbers (n=12; p=0.28). These data suggest that TNF, acting through TNFR2, is involved in the regulation of primordial follicle recruitment. Supported by NIH 38955, T32HD07170, and a grant from the Women's Health Research Group at the University of Maryland.

KEY WORDS: Primordial follicle recruitment, TNF