Follicle growth and development within the ovary has been shown to be regulated by autocrine and paracrine signaling involving several growth factors from granulosa cells, theca cells and the oocyte. Bone morphogenetic protein 4 and its receptor BMPR1B have been shown to be expressed in the ovaries, and a point mutation in BMPR-1B has been linked with abnormal ovulation rate. The objective of current study is to further elucidate the role of BMPRIB in the female reproductive system by investigating passive immune neutralization of BMPRIB in the mouse.
Female mice (21 days old) were divided into 4 groups (n=5), and given daily subcutaneous injections of (i) saline, (ii) anti BMPR1B (50ug), (iii) eCG (2 IU) and both (iv) anti BMPR1b for 7 days. The mice were euthanized and the ovaries weighed and collected in RNA later. The ovaries were stored overnight at 4 C then stored at -80 C until RNA extraction. Extracted RNA was analyzed using RT-qPCR for the following genes: BMP2, BMP4, GDF9, AMH, ACVR1A, ACVR1B, ACVR1C, ACVR2A, ACVR2B, BMPR1A and BMPR1B.
The results show that anti BMPR1B had no effect on the expression of BMP2, BMP4, GDF9 or AMH but there was a significant decrease (P<0.05) in the expression of BMPRIB in all treatment groups compared to control group. The animals treated with eCG lead to significantly increases (P<0.05) the mRNA expression of GDF9 and ACVR1B compared with control group. There were no significant differences in the mRNA expression of ACVR1A, ACVR1C, ACVR2A, ACVR2B between different treatment groups.
0>In summary, anti BMPRIB treatment generally had opposite effects on gene expression to that seen with eCG, which is in line with our previous studies showing BMP1B signalling slowed primordial follicle recruitment while gonadotropins accelerated their recruitment.