reproductive technologies have opened up
possibilities in accelerating genetic gain and
enhancing production potential in livestock .
Artificial insemination (AI).
Multiple ovulation and embryo transfer
In vitro production of embryos.
Marker assisted selection ,and
Transfer of genes between animals.
vitro production of embryos (IVEP)has emerged as a
reliable alternative method to conventional ovarian
super stimulation methods
Important research tool for animal embryology.
studies have clearly demonstrated that, while
the intrinsic quality of the oocyte determines the
proportion of oocytes developing to blastocysts.
post-fertilization culture environment has the
biggest influence on blastocyst quality.
[Russell et al., 2006]
However, the exact influence of culture conditions
during critical events is still unknown.
in vitro maturation (IVM) is a
reproductive technology that enables
mature oocytes to be generated ex vivo.
involves removal of cumulus-oocyte-complexs
(COCs) and culturing them into standard culturing
medium for 24h upto meiosis II.
efficiency of IVM technologies or assisted
reproductive technologies (ARTs) is limited by
The oocyte developmental competence ,and
Subsequent embryo development as compared to in
a) Meiotic Maturation
c) Preimplantation development
d) Development to term /successful pregnancy
gradually and sequentially acquire
developmental competence during the course of
folliculogenesis as the oocyte grows and its
companion somatic cells differentiate.
(Eppig et al., 1994).
(1) The origin of the oocyte.
(2) Follicle health.
(3) Hormonal stimulation.
(Lonergan et al., 1994)
(Blondin et al.,1995)
(Sirard et al., 2006)
(4) Communication between the oocyte and its surrounding
cumulus cells (CCs)
it was thought that oocyte is a passive
recipient of Cumulus Cell function.
now it is evidenced oocyte is a key regulator of
its developmental competence by regulating its micro
environment via the secretion of paracrine molecules
like GDF9 , BMP15 etc.
plays active role throughout folliculogenesis
via secretion of paracrine factors ( like GDF9 &
BMP15) that maintain an appropriate
microenvironment for the acquisition of its
(Dong et al., 1996; Eppig et al., 1997;Gilchrist et al., 2004).
and colleagues demonstrated in 1959 that intact
rabbit preovulatory follicles do not luteinize when
transplanted into the anterior chamber of the eye.
In contrast to oocyte-free explants of either the
follicle wall or granulosa cells that do undergo
Nalbandov and colleagues
confirmed this work using rabbit dominant
follicles in situ, showing that removal of the
oocyte caused spontaneous luteinization of
granulosa and theca cells and elevated secretion
of progesterone to levels produced by corpora
( Nalbandov 1970).
is known that bidirectional interactions occurs
between oocyte and cumulus cells.
interaction occurs via; gap junction and
in growth and development of both oocyte and
( Eppig et al.,1997,2002;Matzuk et al., 2002)
differentiation factor 9 (GDF9)and Bone
morphogenetic protein 15 (BMP15) are two closely
related members of the Transforming Growth Factorβ (TGF-β ) superfamily.
superfamily ; large family of structurally
proliferation, differentiation, development
etc in variety of cells/tissues.
& BMP15 are expressed and translated in
as preproproteins, consisting of a signal
peptide, a large proregion and a mature region.
( Shimasaki et al., 2004)
Lack of 4th cysteine residue (otherwise conserved in
other members of TGF-β superfamily)
mostly as homodimer/and or sometimes as
Required for female fertility: as mutations
(homozygus) leads to infertility due to block in
follicullogenisis at early stage.
GDF9 and BMP 15 have recently been shown to
signal through known TGF-β superfamily receptors
to activate the SMAD intracellular cascade
pathways BMP pathway and TGFβ/activin
pathway which respectively activate SMAD1/5/8 and
utilizes BMP pathway to activate
Proliferation of Granulosa cells
Differentiation of Granulosa cells
Prevention of apoptosis
Inhibition of Luteinization
Cumulus cell expansion
GDF 9 and BMP15 stimulates granulosa cell
proliferation and DNA synthesis.
Expression of Ccnd2 mRNA cell cycle
transcript >>>>>cyclin d 2 protein of cell
Assessed by uptake of [H3]thymidine
(Glichrist et al.,2006)
Oocyte secreted factors i-e,GDF9 & BMP15
differentiates the granulosa cells into mural cells
(MGCs) and cumulus cells (CCs) at antral stage of
MGCs under influence of FSH
under influence of OSFs
(Hussein et.al.,2005;Diaz et al.,2007)
prevent Cumulus Cell apoptosis by
maintaining a localized gradient of antiapoptotic factors within the COC
(Hussein et al., 2005)
Expression of anti-apoptotic gene Bcl2
Suppression of pro-apoptotic protein Bax
Suppression of LH receptor (LHCGR)
( Eppig et al.,1997)
Inhibition of FSH induced progestrone production
Two signaling pathways:(i) Gonadotrophin or epidermal growth factor (EGF)
(ii) Paracrine signals of oocyte (GDF9 &BMP15)
Synthesise extracellular matrix (ECM)
Hyaluronan (HA) major component
tumor necrosis factor alpha induced protein 6 (TNFAIP6)
(Russell et al., 2006)
Prior to the LH surge, cumulus cells require GDF-9 to
support the metabolic cascades such as glycolysis and
(Sugiura et al. 2005).
Evidence for this comes from findings of reduced
cholesterol synthesis from acetate in cumulus-oocyte
complexes of Gdf9 − /−mutant mice.
(Sugiura et al. 2005).
Hussein et al.,2005..
is now clear that oocyte regulates the
cumulus cell functions like differentiation,
apoptosis, expansion, luteinization
cumulus cells provide microenvironment
to oocytes for development
order to increase the efficiency of ARTs
the OSFs (GDF9 & BMP15) may be utilized in