Heat shock reduces developmental competence and alters spindle configuration of bovine oocytes

Ju, Jyh-Cherng; Jiang, S.; Tseng, Jung-Kai; Parks, John E.; Yang, Xiangzhong

doi:10.1016/j.theriogenology.2005.03.025

Cited by 97 publications

(84 citation statements)

References 45 publications

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“…Therefore, the reduced blastocyst total cell number was mainly due to a decrease in the trophectoderm (heat stress group) and TE and ICM (heat stress plus IGF-1 group). These data are in agreement with the previous study by Ju et al [30]. It is intriguing to consider that heat stress with or without IGF-1 during maturation period exerted more deleterious effect on subsequent trophectoderm cells.…”

Section: Discussionsupporting

confidence: 93%

“…These data are in agreement with previous studies [11,30,31]. However, it seems that cleavage rate is not a sufficiently reliable indicator of developmental potential [32].…”

Section: Discussionsupporting

confidence: 90%

“…In this study, the percentage of day 8 blastocyst was decreased by heat stress at the first 12 h of maturation. Previous experiment have shown that heat stress during oocyte in vitro maturation results in retarded embryo development [36] and reduction in blastocyst formation rate [7,30,31,37]. It is thought that heat stress can compromise embryonic development when occurring during maturation.…”

Section: Discussionmentioning

confidence: 99%

“…Secretion of bIFN-τ will be reduced during heat stress condition [41]. Therefore, the decrease of trophectoderm cell number in response to heat stress is likely associated with the postimplantation pregnancy losses during hot seasons [30].…”

Section: Discussionmentioning

confidence: 99%

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Unexpected detrimental effect of Insulin like growth factor-1 on bovine oocyte developmental competence under heat stress

Zhandi

Towhidi

Nasr-Esfahani

et al. 2009

J Assist Reprod Genet

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Purpose To investigate the effects of Insulin like growth factor-1 (IGF-1) on bovine oocyte developmental competence under heat stress. Methods In Experiment 1, bovine cumulus-oocyte complexes (COCs) were cultured at 38.5 or 41°C for the first 12 h of maturation in the presence of either 100 ng/ml human recombinant (hr)-IGF-1 or acetic acid. In Experiment 2, COCs were cultured in 38.5 or 41°C for the first 12 h of maturation in the presence either of 100 ng/ml hr-IGF-1 or acetic acid. After fertilization, putative zygotes were cultured for 8 days.Results In experiment 1, addition of rh-IGF-1 to maturation medium at 38.5°C significantly increased the proportion of M II oocytes and decreased the percentage of TUNEL-positive oocytes compared to the other groups. However, addition of rh-IGF-1 to maturation medium under heat stress increased the percentage of TUNEL-positive oocytes. In experiment 2, addition of rh-IGF-1 under heat sress did not affect cleavage rate, whereas, blastocyst formation rate decreased in heatstressed and heat-stressed plus rh-IGF-1 groups. Similarly, The number of trophectoderm cells and total cell number were decreased in heat-stressed and heat-stressed plus rh-IGF-1 groups and the percentage of TUNEL-positive nuclei were increased in heat-stressed and heat-stressed plus rh-IGF-1 groups compared to the other groups. Conclusion The results of the present study demonstrate that IGF-1 decreases oocyte developmental competence and total cell number and increases TUNEL-positive nuclei at heat stress condition. These unexpected results of IGF-1 during maturation period under heat stress condition warrant further optimizations and investigations.

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Section: Discussionsupporting

confidence: 93%

“…These data are in agreement with previous studies [11,30,31]. However, it seems that cleavage rate is not a sufficiently reliable indicator of developmental potential [32].…”

Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Unexpected detrimental effect of Insulin like growth factor-1 on bovine oocyte developmental competence under heat stress

Zhandi

Towhidi

Nasr-Esfahani

et al. 2009

J Assist Reprod Genet

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“…No relativo à função reprodutiva, já foi demonstrado que o estresse térmico compromete a secreção hormonal (BADINGA et al, 1993;WILSON et al, 1998;ROTH et al, 2000), bem como a capacidade do desenvolvimento oocitário (ROCHA et al, 1998;AL-KATANA-NI;JU et al, 2005), folicular (BADINGA et al, 1993;WILSON et al, 1998;ROTH et al, 2000) e embrionário pré-implantacional (PUTNEY; THATCHER, 1988;.…”

Section: Introductionunclassified

Alterações celulares induzidas pelo estresse térmico em embriões bovinos

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Visitin

et al. 2014

Braz. J. Vet. Res. Anim. Sci.

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ResumoCondições ambientais adversas, tais como altas temperaturas e umidade relativa, causam aumento da temperatura corporal interna (hipertermia) de vacas lactantes, que resultam em estresse térmico e diminuição dos índices de gestação. A susceptibilidade embrionária à temperatura elevada já foi bem caracterizada tanto em experimentos in vivo quanto in vitro. A exposição de embriões bovinos em estágios de zigoto e duas células à temperatura elevada diminui o desenvolvimento embrionário até o estágio de blastocisto. No entanto, o embrião torna-se mais resistente aos efeitos deletérios da temperatura elevada à medida que progride no desenvolvimento. A redução na competência de desenvolvimento embrionária causada pelo estresse térmico deve-se, em parte, às inúmeras alterações citoplasmáticas e nucleares induzidas pela temperatura elevada. No citoplasma embrionário, o choque térmico aumenta o número de mitocôndrias edemaciadas, desorganiza os microtúbulos e os filamentos de actina. No compartimento nuclear, a temperatura elevada induz a fragmentação de DNA característica de apoptose. Essa forma de morte celular é um fenômeno regulado ao longo do desenvolvimento embrionário pré-implantacional, visto que altas temperaturas não ativam a cascata de apoptose em embriões de duas ou quatro células. A apoptose embrionária induzida pelo choque térmico em embriões > 16 célu-las pode ser considerada um mecanismo de controle de qualidade para remoção dos blastômeros danificados, já que o bloqueio da apoptose nestes embriões aumenta ainda mais a susceptibilidade ao choque térmico. Além disso, o estresse térmico também pode afetar o estado redox do embrião, levando a um consequente estresse oxidativo. Palavras-chave:Estresse térmico. Embrião. Bovino. Alterações celulares. AbstractAdverse environmental conditions such as high temperature and humidity increase internal body temperature (hyperthermia) of lactating dairy cows resulting in heat stress and decreased pregnancy rates. Embryonic susceptibility to elevated temperature has been well characterized both in vivo and in vitro. Exposure of zygote and two cells stage bovine embryos to elevated temperature decreases embryonic development to the blastocyst stage. However, the bovine embryo becomes more resistant to the deleterious effects of heat stress as it proceeds in its development. The heat-induced reduction in embryonic developmental competence is due, at least in part, to the numerous cytoplasmic and nuclear changes induced by high temperature. In the embryo cytoplasm heat shock increases the number of swollen mitochondria, disrupts microtubules and microfilaments. In the nuclear compartment, elevate temperature induces DNA fragmentation characteristic of apoptosis. This form of cell death is a phenomenon regulated throughout the preimplantation embryonic development, since high temperatures do not trigger apoptosis in embryos of two or four cells. Heat-induced apoptosis in embryos > 16 cells can be seen as a quality control mechanism for removing damaged blastomeres, sinc...

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Managing Reproduction During Heat Stress in Dairy Cows

Hansen

2011

Dairy Production Medicine

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Heat stress can compromise reproductive function of lactating dairy cows throughout much of the world. Among the key events associated with reduced reproductive function are reduced expression of estrus, disruptions in follicular and oocyte function, increased embryonic mortality, and reductions in fetal development. Reproductive function during heat stress can be improved by modifying animal housing to reduce the magnitude of heat stress. In addition, manipulation of physiological function can mitigate some deleterious effects of heat stress. Effects on estrus detection can be reduced by incorporation of estrus detection aids and eliminated by utilization of timed artifi cial insemination protocols. Effects on fertility can be reduced by use of embryo transfer. Other approaches, such as feeding antioxidants, offer some promise for improving fertility, whereas others, such as hormonal treatments, have not resulted in consistent improvements in fertility during heat stress. In the future, it may be possible to select cows for resistance to heat stress as genetic markers for thermotolerance at the physiological and cellular level are identifi ed.Heat stress adversely affects fertility of dairy cattle in most temperate regions of the world where dairy cattle are raised. The magnitude and duration of the reduction in fertility during seasonal heat stress is greater in Dairy Production Medicine, First Edition. Edited by Carlos A. Risco, Pedro Melendez Retamal.

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Heat shock reduces developmental competence and alters spindle configuration of bovine oocytes

Cited by 97 publications

References 45 publications

Unexpected detrimental effect of Insulin like growth factor-1 on bovine oocyte developmental competence under heat stress

Unexpected detrimental effect of Insulin like growth factor-1 on bovine oocyte developmental competence under heat stress

Alterações celulares induzidas pelo estresse térmico em embriões bovinos

Managing Reproduction During Heat Stress in Dairy Cows

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