In vitro maturation of bovine oocytes in the presence of growth hormone accelerates nuclear maturation and promotes subsequent embryonic development

Abstract

Regulatory effect of GH on follicular growth and development in the cow is well documented. The aim of this study was to investigate the role of GH on in vitro bovine oocyte maturation. Therefore bovine cumulus oocyte complexes (COCs) were cultured in M199 without FCS and gonadotropins and in the presence of 10, 100, or 1,000 ng/ml bovine GH (NIH-GH-B18). The COCs were incubated at 39 degrees C in a humidified atmosphere with 5% CO2 in air and nuclear stage was assessed after 2, 4, 8, 16, 22, and 24 hr of incubation using DAPI staining. To assess the effect of GH on developmental capacity of the oocytes, COCs were incubated in the presence of GH for 22 hr, followed by IVF and in vitro embryo culture. Cultures without GH served as controls. For subsequent development, the embryos were cultured in M199 supplemented with 10% FCS on a monolayer of BRL cells. Embryos were scored morphologically and the efficiency of the culture system was evaluated as (1) the percentage of cleaved embryos 4 days after IVF, (2) the percentage of blastocysts on day 9 expressed on the basis of the number of oocytes at the onset of culture, and (3) the percentage of hatched blastocysts on day 11 expressed on the basis of the total number of blastocysts present at day 9. GH (100 and 1,000 ng/ml) significantly accelerated nuclear maturation (P < 0.001). At 4 and 8 h the percentage of oocytes in GV stage after GH treatment (54% and 19%) was significantly lower than the control (64% and 41%). Similarly at 16 and 22 h the percentage of oocytes in MII stage was significantly higher in the GH-treated group; (58% and 77%) and (46% and 62%) for GH and control respectively. The number of oocytes in MII beyond 22 hr of culture did not differ; 100 and 1,000 ng/ml GH induced significant cumulus expansion (P < 0.05), which was not observed in the absence of GH. Addition of 100 and 1,000 ng/ml GH during maturation significantly (P < 0.01) enhanced subsequent cleavage rate from (64% and 67%) in control to (75% and 81%) in GH-treated group; embryonic development in terms of day 9 blastocyst formation was also significantly increased in the presence of GH (29% and 34%) compared to the control (18% and 24%). The hatchability of the blastocysts was not influenced by GH. From the present data, it can be concluded that GH present during IVM has a beneficial effect on subsequent development.

Improvement of the Culture Conditions for In Vitro Production of Cattle Embryos in a Portable CO2 Incubator

“…This trend was almost maintained up to the transferable embryos stage, despite the fact that the latter was, however, not signi®cantly dierent. Similar results have also been documented for the in vitro culture of oocytes from dierent species such as rat (Apa et al 1994), porcine (Hagen and Graboski 1990), and bovine (Izadyar et al 1996); particularly during the process of nuclear maturation. There are two possible means by which GH is thought to positively aect the IVM and development of the oocytes.…”

“…Similar results have also been documented for the in vitro culture of oocytes from different species such as rat (Apa et al. 1994), porcine (Hagen and Graboski 1990), and bovine (Izadyar et al. 1996); particularly during the process of nuclear maturation.…”

Improvement of the Culture Conditions for In Vitro Production of Cattle Embryos in a Portable CO2 Incubator

“…This trend was almost maintained up to the transferable embryos stage, despite the fact that the latter was, however, not signi®cantly dierent. Similar results have also been documented for the in vitro culture of oocytes from dierent species such as rat (Apa et al 1994), porcine (Hagen and Graboski 1990), and bovine (Izadyar et al 1996); particularly during the process of nuclear maturation. There are two possible means by which GH is thought to positively aect the IVM and development of the oocytes.…”

“…Similar results have also been documented for the in vitro culture of oocytes from different species such as rat (Apa et al. 1994), porcine (Hagen and Graboski 1990), and bovine (Izadyar et al. 1996); particularly during the process of nuclear maturation.…”

Stimulatory effect of growth hormone on in vitro maturation of bovine oocytes is exerted through cumulus cells and not mediated by IGF-I

“…Culture of denuded oocytes for 16 hr in the presence of 100 ng/ml bGH did not change the proportion of MII oocytes compared to culture of denuded oocytes without bGH (Table 1). In contrast, culture for 16 hr of cumulusenclosed oocytes in the presence of 100 ng/ml bGH significantly increased the proportion of MII oocytes as compared to culture of cumulus-enclosed oocytes without bGH, according to our previous study (Izadyar et al, 1996). Culture of denuded oocytes for 7 hr in the presence of 100 ng/ml GH resulted in a significant delay of GVBD (Table 2).…”

“…In a previous study we showed that in vitro maturation of bovine oocytes in the presence of GH accelerates nuclear maturation and has a beneficial effect on subsequent embryonic development (Izadyar et al, 1996). In addition, significant cumulus expansion was observed in the presence of GH.…”

The effects of platelet lysate on maturation, fertilization and embryo development of NMRI mouse oocytes at germinal vesicle stage

“…In general, cumulus cells improve nuclear and cytoplasmic maturation by secreting factors such as gonadotropin-releasing hormone (GnRH), pituitary adenylate cyclase-activating polypeptide (PACAP), EGF, IGF, activin, inhibin and follistatin through the gap junction [29][30][31][32]. Oocytes matured in the presence of growth factors like EGF and IGF show an acceleration of nuclear and cytoplasmic maturation as well as a higher fertilization rate [33]. Therefore, it seems that the presence of cumulus cells is essential for oocyte maturation and subsequent fertilization.…”

Improvement of the Culture Conditions for In Vitro Production of Cattle Embryos in a Portable CO2 Incubator

“…This trend was almost maintained up to the transferable embryos stage, despite the fact that the latter was, however, not signi®cantly dierent. Similar results have also been documented for the in vitro culture of oocytes from dierent species such as rat (Apa et al 1994), porcine (Hagen and Graboski 1990), and bovine (Izadyar et al 1996); particularly during the process of nuclear maturation. There are two possible means by which GH is thought to positively aect the IVM and development of the oocytes.…”

“…Similar results have also been documented for the in vitro culture of oocytes from different species such as rat (Apa et al. 1994), porcine (Hagen and Graboski 1990), and bovine (Izadyar et al. 1996); particularly during the process of nuclear maturation.…”

Stimulatory effect of growth hormone on in vitro maturation of bovine oocytes is exerted through cumulus cells and not mediated by IGF-I

“…Culture of denuded oocytes for 16 hr in the presence of 100 ng/ml bGH did not change the proportion of MII oocytes compared to culture of denuded oocytes without bGH (Table 1). In contrast, culture for 16 hr of cumulusenclosed oocytes in the presence of 100 ng/ml bGH significantly increased the proportion of MII oocytes as compared to culture of cumulus-enclosed oocytes without bGH, according to our previous study (Izadyar et al, 1996). Culture of denuded oocytes for 7 hr in the presence of 100 ng/ml GH resulted in a significant delay of GVBD (Table 2).…”

“…In a previous study we showed that in vitro maturation of bovine oocytes in the presence of GH accelerates nuclear maturation and has a beneficial effect on subsequent embryonic development (Izadyar et al, 1996). In addition, significant cumulus expansion was observed in the presence of GH.…”

The effects of platelet lysate on maturation, fertilization and embryo development of NMRI mouse oocytes at germinal vesicle stage

“…In general, cumulus cells improve nuclear and cytoplasmic maturation by secreting factors such as gonadotropin-releasing hormone (GnRH), pituitary adenylate cyclase-activating polypeptide (PACAP), EGF, IGF, activin, inhibin and follistatin through the gap junction [29][30][31][32]. Oocytes matured in the presence of growth factors like EGF and IGF show an acceleration of nuclear and cytoplasmic maturation as well as a higher fertilization rate [33]. Therefore, it seems that the presence of cumulus cells is essential for oocyte maturation and subsequent fertilization.…”

Improvement of the Culture Conditions for In Vitro Production of Cattle Embryos in a Portable CO2 Incubator

“…This trend was almost maintained up to the transferable embryos stage, despite the fact that the latter was, however, not signi®cantly dierent. Similar results have also been documented for the in vitro culture of oocytes from dierent species such as rat (Apa et al 1994), porcine (Hagen and Graboski 1990), and bovine (Izadyar et al 1996); particularly during the process of nuclear maturation. There are two possible means by which GH is thought to positively aect the IVM and development of the oocytes.…”

“…Similar results have also been documented for the in vitro culture of oocytes from different species such as rat (Apa et al. 1994), porcine (Hagen and Graboski 1990), and bovine (Izadyar et al. 1996); particularly during the process of nuclear maturation.…”

Stimulatory effect of growth hormone on in vitro maturation of bovine oocytes is exerted through cumulus cells and not mediated by IGF-I

“…Culture of denuded oocytes for 16 hr in the presence of 100 ng/ml bGH did not change the proportion of MII oocytes compared to culture of denuded oocytes without bGH (Table 1). In contrast, culture for 16 hr of cumulusenclosed oocytes in the presence of 100 ng/ml bGH significantly increased the proportion of MII oocytes as compared to culture of cumulus-enclosed oocytes without bGH, according to our previous study (Izadyar et al, 1996). Culture of denuded oocytes for 7 hr in the presence of 100 ng/ml GH resulted in a significant delay of GVBD (Table 2).…”

“…In a previous study we showed that in vitro maturation of bovine oocytes in the presence of GH accelerates nuclear maturation and has a beneficial effect on subsequent embryonic development (Izadyar et al, 1996). In addition, significant cumulus expansion was observed in the presence of GH.…”

The effects of platelet lysate on maturation, fertilization and embryo development of NMRI mouse oocytes at germinal vesicle stage

“…In general, cumulus cells improve nuclear and cytoplasmic maturation by secreting factors such as gonadotropin-releasing hormone (GnRH), pituitary adenylate cyclase-activating polypeptide (PACAP), EGF, IGF, activin, inhibin and follistatin through the gap junction [29][30][31][32]. Oocytes matured in the presence of growth factors like EGF and IGF show an acceleration of nuclear and cytoplasmic maturation as well as a higher fertilization rate [33]. Therefore, it seems that the presence of cumulus cells is essential for oocyte maturation and subsequent fertilization.…”