Influence of equine growth hormone, insulin-like growth factor-I and its interaction with gonadotropins on in vitro maturation and cytoskeleton morphology in equine oocytes.
Abstract: In horses, successful in vitro fertilization procedures are limited by our inability to consistently mature equine oocytes by in vitro methods. Growth hormone (GH) is an important regulator of female reproduction in mammals, playing an important role in ovarian function, follicular growth and steroidogenesis. The objectives of this research were to investigate: the effects of equine growth hormone (eGH) and insulin-like growth factor-I (IGF-I) on the in vitro maturation (IVM) of equine oocytes, and the effects of eGH in addition to estradiol (E2), gonadotropins (FSH and LH) and fetal calf serum (FCS) on IVM. We also evaluated the cytoskeleton organization of equine oocytes after IVM with eGH. Equine oocytes were aspirated from follicles <30 mm in diameter and matured for 30 h at 38.5°C in air with 5% CO2. In experiment 1, selected cumulus-oocyte complexes (COCs) were randomly allocated as follows: (a) control (no additives); (b) 400 ng/ml eGH; (c) 200 ng/ml IGF-I; (d) eGH + IGF-I; and (e) eGH + IGF-I + 200 ng/ml anti-IGF-I. In addition to these treatment groups, we also added 1 μg/ml E2, 5 IU/ml FSH, 10 IU/ml LH and 10% FCS in vitro (experiment 2). Oocytes were stained with markers for microtubules (anti-α-tubulin antibody), microfilaments (AlexaFluor 488 Phalloidin) and chromatin (TO-PRO3-iodide) and assessed via confocal microscopy. No difference was observed when eGH and IGF-I was added into our IVM system. However, following incubation with eGH alone (40%) and eGH, E2, gonadotropins and FCS (36.6%) oocytes were classified as mature v. 17.6% of oocytes in the control group (P < 0.05). Matured equine oocytes showed that a thin network of filaments concentrated within the oocyte cortex and microtubules at the metaphase spindle showed a symmetrical barrel-shaped structure, with chromosomes aligned along its midline. We conclude that the use of E2, gonadotropins and FCS in the presence of eGH increases the number of oocytes reaching oocyte competence.
Publication Date: 2013-06-21 PubMed ID: 23790355DOI: 10.1017/S175173111300116XGoogle Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The researchers studied the effects of equine growth hormone (eGH) and insulin-like growth factor-I (IGF-I), as well as their interaction with gonadotropins, on the in vitro maturation of horse oocytes. They found that using eGH, E2, gonadotropins, and FCS increased the number of oocytes reaching maturation.
Objective of the Study
- The main objective of this research was to investigate the effects of equine growth hormone (eGH) and insulin-like growth factor-I (IGF-I) as well as the role of estradiol (E2), gonadotropins (FSH and LH) and fetal calf serum (FCS) in promoting in vitro maturation (IVM) of horse oocytes. Beyond these factors, the researchers also aimed to evaluate the cytoskeleton organization of horse oocytes after IVM with eGH.
Methodology
- The researchers aspirated equine oocytes from follicles smaller than 30 mm in diameter and matured them for 30 hours at 38.5 degrees Celsius in an atmosphere with 5% CO2.
- The selected cumulus-oocyte complexes (COCs) were allocated to five different experimental groups: a control group with no additives, a group with eGH, a group with IGF-I, a group with both eGH and IGF-I, and a group with eGH, IGF-I, and an anti-IGF-I substance. Additionally, some groups were also treated with E2, FSH, LH, and FCS.
- The oocytes were stained with markers for microtubules, microfilaments, and chromatin and then examined under a confocal microscope.
Results of the Study
- There were no observable differences when eGH and IGF-I were added to the IVM system. However, the study found a significant increase in the maturation of oocytes when they were incubated with eGH alone or with the combined application of eGH, E2, gonadotropins, and FCS.
- The matured equine oocytes revealed a thin filament network concentrated within the oocyte cortex and microtubules at the metaphase spindle displayed a symmetrical barrel-shaped structure, with chromosomes lined up along its center.
Conclusion
- The researchers concluded that the use of eGH in the presence of E2, gonadotropins, and FCS increases the number of oocytes reaching maturation, suggesting a potential methodology for improving in vitro maturation of horse oocytes. This might help to overcome current limitations in successful in vitro fertilization procedures in horses.
Cite This Article
APA
Pereira GR, Lorenzo PL, Carneiro GF, Ball BA, Pegoraro LM, Pimentel CA, Liu IK.
(2013).
Influence of equine growth hormone, insulin-like growth factor-I and its interaction with gonadotropins on in vitro maturation and cytoskeleton morphology in equine oocytes.
Animal, 7(9), 1493-1499.
https://doi.org/10.1017/S175173111300116X Publication
Researcher Affiliations
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA 95616, USA. gabriel.pereira@ufpel.edu.br
MeSH Terms
- Animals
- Cytoskeleton / drug effects
- Cytoskeleton / physiology
- Female
- Gonadotropins / metabolism
- Growth Hormone / metabolism
- Growth Hormone / pharmacology
- Horses / physiology
- In Vitro Oocyte Maturation Techniques / methods
- Insulin-Like Growth Factor I / metabolism
- Insulin-Like Growth Factor I / pharmacology
- Microscopy, Confocal / veterinary
- Oocytes / cytology
- Oocytes / drug effects
- Oocytes / physiology
Citations
This article has been cited 4 times.- Kulus J, Kranc W, Kulus M, Dzięgiel P, Bukowska D, Mozdziak P, Kempisty B, Antosik P. Expression of genes regulating cell division in porcine follicular granulosa cells. Cell Div 2023 Aug 7;18(1):12.
- Deng K, Du D, Fan D, Pei Z, Zhang S, Xu C. Growth Hormone Promotes Oocyte Maturation In Vitro by Protecting Mitochondrial Function and Reducing Apoptosis. Reprod Sci 2023 Jul;30(7):2219-2230.
- Li Y, Liu H, Yu Q, Liu H, Huang T, Zhao S, Ma J, Zhao H. Growth Hormone Promotes in vitro Maturation of Human Oocytes. Front Endocrinol (Lausanne) 2019;10:485.
- Salazar-Ortiz J, Monget P, Guillaume D. The influence of nutrition on the insulin-like growth factor system and the concentrations of growth hormone, glucose, insulin, gonadotropins and progesterone in ovarian follicular fluid and plasma from adult female horses (Equus caballus). Reprod Biol Endocrinol 2014 Jul 31;12:72.
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