193 INSULIN-LIKE GROWTH FACTOR-1 EXERTS A THERMOPROTECTIVE ROLE ON MITOCHONDRIAL FUNCTION OF BOVINE OOCYTES EXPOSED TO HEAT SHOCK

2012 ◽  
Vol 24 (1) ◽  
pp. 209 ◽  
Author(s):  
J. Ispada ◽  
R. S. Lima ◽  
P. H. B Risolia ◽  
M. E. O. A. Assumpção ◽  
J. A. Visintin ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Growth Factor ◽  
Heat Shock ◽  
Mitochondrial Function ◽  
Control Group ◽  
Mitochondrial Activity ◽  
Insulin Like Growth Factor ◽  
Bovine Oocyte ◽  
Bovine Oocytes ◽  
Apoptotic Cascade

The series of events associated with oocyte maturation are susceptible to disruption by elevated temperature. These events are regulated by a variety of growth factors, such as insulin-like growth factor-1 (IGF-1). Exposure of bovine oocytes to heat shock compromises oocyte competence and triggers apoptosis. It has been shown that cellular stresses often alter mitochondrial function and activate the mitochondrial apoptotic cascade. Therefore, the objective of this study was to determine the effect of heat shock on bovine oocyte mitochondrial activity and the role of IGF-1 in this context. Slaughterhouse derived cumulus–oocyte complexes (COC) were subjected to control (38.5°C for 22 h) and heat shock (41°C for 14 h, followed by 38.5°C for 8 h) treatments in the presence of 0 or 100 ng mL–1 of IGF-1 during in vitro maturation (IVM). After 22 h, IVM COC were mechanically denuded and subjected to MitoTracker Red CMX-Ros assay (Invitrogen M-7512) to localize and quantify active mitochondria. Denuded oocytes were incubated in TCM-199-HEPES containing 10 μg mL–1 of polyvinyl alcohol and 50 nM MitoTracker at 37°C for 15 min. Oocytes were evaluated under fluorescence microscope and digital images were obtained and stored as TIFF files. Mitochondrial activity from each oocyte was quantified using the software Image J 1.43. This experiment was replicated 6 times using 97 to 204 COC/treatment. Data were analyzed by least-squares analysis of variance using the general linear model procedure of SAS. In the absence of IGF-1, heat shock reduced (P < 0.001) mitochondrial activity from 64.31 ± 1.91 to 56.74 ± 1.26 arbitrary units for control and heat shock groups, respectively. Addition of IGF-1 to maturation medium did not affect mitochondrial activity in the control group (66.25 ± 1.56). However, IGF-1 improved (temperature × IGF-1; P < 0.001) mitochondrial activity of bovine oocytes subjected to heat shock (70.32 ± 1.32). In conclusion, heat shock reduced bovine oocyte mitochondrial activity, suggesting activation of mitochondrial apoptotic cascade. Moreover, IGF-1 exerted a thermoprotective role, reducing the mitochondrial damage caused by elevated temperature.

255 EXAMINING THE EFFECTS OF INSULIN-LIKE GROWTH FACTOR-I ON THE MATURATION AND DEVELOPMENTAL COMPETENCE OF BOVINE OOCYTES EXPOSED TO HEAT SHOCK

2013 ◽  
Vol 25 (1) ◽  
pp. 275
Author(s):  
Q. Meiyu ◽  
Z. Roth
Keyword(s):  
Growth Factor ◽  
Heat Shock ◽  
Control Group ◽  
Cortical Granule ◽  
Insulin Like Growth Factor ◽  
Cell Stage ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I ◽  
Bovine Oocytes

Insulin-like growth factor-I (IGF-I) has been suggested as a survival factor for pre-implantation bovine embryos exposed to heat shock (HS). Therefore, the aims of the study were 1) to examine the protective effects of IGF-I on the developmental competence of bovine oocytes exposed to HS, particularly the effects on oocyte cytoplasmic and nuclear maturation, and 2) to examine whether IGF-I administration contracts HS-induced apoptosis in bovine oocytes. In vitro maturation/IVF/in vitro-production procedures were performed as described previously by Gendelman and Roth (2012). Briefly, cumulus–oocyte complexes (n = 250 to 300/group; 5 replicates) were matured (TCM-199 with Earle’s salts; 22 h, 5% CO2) at 38.5°C or exposed to HS (41°C) with or without 100 µg of IGF-I (Sigma, St. Louis, MO, USA). Matured oocytes were IVF (18 h, 38.5°C, 5% CO2) and cultured in K simplex optimized medium (38.5°C, 5% CO2, 5% O2) for 8 days. Cleavage rates for 2- and 4-cell-stage embryos were assessed at 42 h post-fertilization. For each experimental group, a subgroup of matured oocytes (n = 50) was examined at the end of maturation for nuclear status (1 µg mL–1 of Hoechst 33342, Sigma), cortical granule migration (fluorescein isothiocyanate-Lens culinaris agglutinin, Sigma) and apoptotic status (TUNEL, Roche, Basel, Switzerland). Data were analysed by one-way ANOVA (JMP-6, SAS Institute Inc., Cary, NC, USA) followed by Student’s t-test. Data are presented as mean ± SE. The proportion of oocytes that cleaved to the 2- to 4-cell-stage embryos was lower in the HS group than in the control group (56.55 ± 4.49% v. 75.6 ± 4.16%, respectively; P < 0.05). Although not significant, IGF-I increased the proportions of heat-stressed oocytes that cleaved to the 2- to 4-cell stage (62.32 ± 4.49% v. 56.55 ± 4.49%, for HS + IGF-I and HS, respectively). Neither maturation at 41.5°C nor IGF-I supplementation had any effect on cortical granule migration because the proportions of oocytes with a type I, type II, and type III cortical granule distribution were similar in the control and HS groups. However, the proportion of oocytes that underwent nuclear maturation (i.e. having a nucleus at the telophase-I or metaphase-II stages) was significantly lower in the HS group than in the control group (P < 0.01), and IGF-I slightly increased their proportion in HS oocytes (nonsignificant). The proportion of TUNEL-positive oocytes tended to be higher in the HS group compared with the control group (47.9 ± 12.2% v. 28.0 ± 12.2%, respectively; P ≤ 0.09), and IGF-I decreased the proportion of TUNEL-positive oocytes in the HS group to a level (27.4 ± 12.2%) similar to that noted in the control group. In summary, exposing bovine oocytes to a physiologically relevant thermal stress impaired their ability to undergo first cleavages, most likely because of alteration in nuclear rather than cytoplasmic maturation. Insulin-like growth factor-I was found to slightly alleviate the deleterious effects of heat shock on bovine oocytes.

Role of insulin-like growth factor 1 on cross-bred Bos indicus cattle germinal vesicle oocytes exposed to heat shock

2017 ◽  
Vol 29 (7) ◽  
pp. 1405 ◽  
Author(s):  
Rafaela S. Lima ◽  
Pedro H. B. Risolia ◽  
Jéssica Ispada ◽  
Mayra E. O. A. Assumpção ◽  
José A. Visintin ◽  
...  
Keyword(s):  
Growth Factor ◽  
Heat Shock ◽  
Bos Indicus ◽  
Germinal Vesicle ◽  
Cell Number ◽  
Developmental Competence ◽  
Mitochondrial Activity ◽  
Insulin Like Growth Factor ◽  
Cellular Mechanisms ◽  
Cleavage Rate

Germinal vesicle (GV) oocytes are susceptible to heat stress. However, neither the cellular mechanisms triggered by elevated temperature nor the thermoprotective effects of insulin-like growth factor (IGF) on GV oocytes are completely understood. Therefore, a series of experiments was conducted to determine the direct effects of IGF1 (0, 12.5, 25, 50 and 100 ng mL–1) on heat-treated GV oocytes. Butyrolactone-arrested GV oocytes were cultured at 38.5°C (control) or 41°C (heat shock; HS) for 14 h in the presence of different concentrations of IGF1. Exposure of GV oocytes to 41°C increased (P < 0.05) the number of terminal deoxyribonucleotidyl transferase-mediated fluorescein-dUTP nick end-labelling (TUNEL)-positive oocytes. At concentrations of 12.5 and 25 ng mL–1, IGF1 tended to minimise these negative effect of HS (P = 0.07). However, neither HS nor IGF1 had any effect on caspase activity. HS also decreased (P < 0.05) GV oocyte mitochondrial activity and developmental competence to the blastocyst stage. These deleterious effects of HS were alleviated (P < 0.05) by 12.5 ng mL–1 IGF1. This concentration of IGF1 did not affect cleavage rate, the percentage of TUNEL-positive blastomeres and total blastocyst cell number regardless of temperature. In conclusion, exposure of GV oocytes to HS triggered the apoptotic cascade and compromised oocyte developmental competence. Physiological concentrations of IGF1 had a beneficial effect on heat-shocked GV oocytes.

scholarly journals The Role of Insulin-Like Growth Factor-I on Developmental Competence of Bovine Oocytes Exposed to Heat Shock.

2011 ◽  
Vol 85 (Suppl_1) ◽  
pp. 330-330 ◽  
Author(s):  
Pedro H.B. Risolia ◽  
Rafaela S. Lima ◽  
Jessica Ispada ◽  
Mayra E.O.D. Assumpcao ◽  
Jose A. Visintin ◽  
...  
Keyword(s):  
Growth Factor ◽  
Heat Shock ◽  
Developmental Competence ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Growth Factor I ◽  
Bovine Oocytes

scholarly journals Thermoprotective effect of insulin-like growth factor 1 on in vitro matured bovine oocyte exposed to heat shock

2016 ◽  
Vol 86 (8) ◽  
pp. 2028-2039 ◽  
Author(s):  
Thaís A. Rodrigues ◽  
Jessica Ispada ◽  
Pedro H.B. Risolia ◽  
Mariana T. Rodrigues ◽  
Rafaela S. Lima ◽  
...  
Keyword(s):  
Growth Factor ◽  
Heat Shock ◽  
Insulin Like Growth Factor ◽  
Bovine Oocyte

Long-term treadmill training ameliorates endothelium-dependent vasorelaxation mediated by insulin and insulin-like growth factor-1 in hypertension

2015 ◽  
Vol 119 (6) ◽  
pp. 663-669 ◽  
Author(s):  
Yi-Yuan Lin ◽  
Shin-Da Lee ◽  
Chia-Ting Su ◽  
Tsung-Lin Cheng ◽  
Ai-Lun Yang
Keyword(s):  
Growth Factor ◽  
Insulin Receptor ◽  
Treadmill Training ◽  
Control Group ◽  
Insulin Like Growth Factor ◽  
Hypertensive Rats ◽  
Protein Levels ◽  
Significant Difference ◽  
Nos Inhibitors

Dysfunction of insulin and insulin-like growth factor-1 (IGF-1) is associated with the pathophysiology of hypertension. The influence of long-term exercise on vascular dysfunction caused by hypertension remains unclear. We investigated whether long-term treadmill training improved insulin- and IGF-1-mediated vasorelaxation in hypertensive rats. Eight-week-old male spontaneously hypertensive rats (SHR) were randomly divided into sedentary and exercise (SHR-EX) groups. The SHR-EX group was trained on a treadmill for 60 min/day, 5 days/wk, for 8 wk. Wistar-Kyoto rats (WKY) were used as the normal control group. After training, aortic insulin- and IGF-1-mediated vasorelaxation was evaluated in organ baths. Additionally, the roles of phosphatidylinositol 3-kinase (PI3K), nitric oxide synthase (NOS), and aortic protein expression were examined in the three groups. Compared with sedentary SHR and WKY groups, insulin- and IGF-1-mediated vasorelaxation was significantly enhanced to a nearly normal level in the SHR-EX group. After endothelial denudation, blunted and comparable vasorelaxation was found among the three groups. Pretreatment with selective PI3K and NOS inhibitors attenuated insulin- and IGF-1-mediated vasorelaxation, and no significant difference was found among the three groups after the pretreatment. The aortic protein levels of the insulin receptor (IR), IGF-1 receptor (IGF-1R), insulin receptor substrate-1 (IRS-1), and endothelial NOS (eNOS) were also significantly increased in the SHR-EX group compared with the other two groups. These results suggested that treadmill training elicited the amelioration of endothelium-dependent insulin/IGF-1-mediated vasorelaxation partly via the increased activation of PI3K and NOS, as well as the enhancement of protein levels of IR, IGF-1R, IRS-1, and eNOS, in hypertension.

H1foo is essential for in vitro meiotic maturation of bovine oocytes

Zygote ◽  
2014 ◽  
Vol 23 (3) ◽  
pp. 416-425 ◽  
Author(s):  
Yan Yun ◽  
Peng An ◽  
Jing Ning ◽  
Gui-Ming Zhao ◽  
Wen-Lin Yang ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
Polar Body ◽  
Linker Histone ◽  
Meiotic Maturation ◽  
Control Group ◽  
Bovine Oocyte ◽  
First Polar Body ◽  
Effective Sirnas ◽  
Bovine Oocytes

SummaryOocyte-specific linker histone, H1foo, is localized on the oocyte chromosomes during the process of meiotic maturation, and is essential for mouse oocyte maturation. Bovine H1foo has been identified, and its expression profile throughout oocyte maturation and early embryo development has been established. However, it has not been confirmed if H1foo is indispensable during bovine oocyte maturation. Effective siRNAs against H1foo were screened in HeLa cells, and then siRNA was microinjected into bovine oocytes to down-regulate H1foo expression. H1foo overexpression was achieved via mRNA injection. Reverse transcription polymerase chain reaction (RT-PCR) results indicated that H1foo was up-regulated by 200% and down-regulated by 70%. Based on the first polar body extrusion (PB1E) rate, H1foo overexpression apparently promoted meiotic progression. The knockdown of H1foo significantly impaired bovine oocyte maturation compared with H1foo overexpression and control groups (H1foo overexpression = 88.7%, H1foo siRNA = 41.2%, control = 71.2%; P < 0.05). This decrease can be rescued by co-injection of a modified H1foo mRNA that has escaped from the siRNA target. However, the H1e (somatic linker histone) overexpression had no effect on PB1E rate when compared with the control group. Therefore we concluded that H1foo is essential for bovine oocyte maturation and its overexpression stimulates the process.

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