Regulatory Effect of Granulocyte-Colony Stimulating Factor on Natriuretic Peptide Precursor Type C during Pre-Ovulatory Period and Successful Implantation of Embryos from Mating in NMRI Mice

Background: Natriuretic peptide precursor type C (NPPC) is expressed by ovarian follicles. This factor participating in the maintenance of oocyte meiotic arrest at the diplotene stage of prophase I for a long time. G-CSF (Granulocyte-colony stimu-lating factor) is one of the hematopoietic growth factors and produce in developing follicles, fetal and reproductive tissues. G-CSF has recently been shown to be involved in oocyte matu-ration and ovulation. In this study we determined whether or not G-CSF plays a role in the regulation of NPPC in resumption of oocyte meiosis and also its effect on fetuses.Materials and Methods: Immature female NMRI mice were randomly assigned to control and treatment groups were in-jected i.p. with 10 IU of PMSG (Pregnant Mare s Serum Gon-adotropin) to stimulate follicle development. Treatment group were received G-CSF (50μg / kg i.p.), at the time of PMSG administration, while the control group had the same volume of normal saline instead of G-CSF at the same time. 48 hours post-PMSG administration Pre-ovulatory follicles were collected for quantitative real-time PCR analyses. Also, the above agents were injected into mature mice and 48h after injecting PMSG, in order to stimulate ovulation in mature mice injected i.p. with 10 IU hCG (Human chorionic gonadotropin). On day 16 post coitus, the mature female mice of both groups were sacrificed for withdrawing their fetuses to determine their specification. Results: The expression levels of NPPC have a significant de-crease (P <0.05) in the treatment group compared to the con-trol group. In other hand the weight of fetus in treatment group (0.771 ± 0.028) were significantly more than that of control group (0.667 ± 0.026) (P<0.05). Also no significant changes were found between follicle count, fetal number, CRL (Crown rump length), implantation and absorbed embryo.Conclusion: GCSF by reducing the expression of the NPPC gene may increase fetal growth.

Keywords:

G-CSF , NPPC , Gene Expression , Fetus , Mice