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Intrauterine ischemic reperfusion switches the fetal transcriptional pattern from HIF-1α- to P53-dependent regulation in the murine brain.

Dong Y, Ito T, Velayo C, Sato T, Iida K, Endo M, Funamoto K, Sato N, Yaegashi N, Kimura Y - PLoS ONE (2014)

Bottom Line: In the present work, pregnant mice were exposed to IR on day 18 of gestation by clipping one side of the maternal uterine horn.Interestingly, significant changes in mRNA levels for both HIF-1α and p53 were apparent and gene regulation patterns were observed to switch from a HIF-1α-dependent to a p53-dependent process.Moreover, pre-treatment with pifithrin-α, a p53 inhibitor, inhibited protein synthesis almost completely, revealing the possibility of preventing fetal brain damage by prophylactic pifithrin-α treatment.

View Article: PubMed Central - PubMed

Affiliation: Advanced Interdisciplinary Biomedical Engineering, Tohoku University Graduate School of Medicine, Sendai, Japan.

ABSTRACT
Ischemic reperfusion (IR) during the perinatal period is a known causative factor of fetal brain damage. So far, both morphologic and histologic evidence has shown that fetal brain damage can be observed only several hours to days after an IR insult has occurred. Therefore, to prevent fetal brain damage under these circumstances, a more detailed understanding of the underlying molecular mechanisms involved during an acute response to IR is necessary. In the present work, pregnant mice were exposed to IR on day 18 of gestation by clipping one side of the maternal uterine horn. Simultaneous fetal electrocardiography was performed during the procedure to verify that conditions resulting in fetal brain damage were met. Fetal brain sampling within 30 minutes after IR insult revealed molecular evidence that a fetal response was indeed triggered in the form of inhibition of the Akt-mTOR-S6 synthesis pathway. Interestingly, significant changes in mRNA levels for both HIF-1α and p53 were apparent and gene regulation patterns were observed to switch from a HIF-1α-dependent to a p53-dependent process. Moreover, pre-treatment with pifithrin-α, a p53 inhibitor, inhibited protein synthesis almost completely, revealing the possibility of preventing fetal brain damage by prophylactic pifithrin-α treatment.

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An ischemic reperfusion in pregnant mice.(A) Experimental design (B) No IR treatment pregnant mice and Ischemic reperfusion (IR) mice underwent surgery on day 18 of gestation. (C). Fetal electrocardiography (FECG) was used to monitor the conditions of both the mother and the fetuses in either clipped or non-clipped uterine horns (n = 5 fetuses from at least 5 individual pregnant mice). (C) Measurement of oxygen concentration in the amniotic fluid before and after IR (p<0.01 indicated as two stars, n = 5 fetuses from at least 3 individual pregnant mice).
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pone-0110577-g001: An ischemic reperfusion in pregnant mice.(A) Experimental design (B) No IR treatment pregnant mice and Ischemic reperfusion (IR) mice underwent surgery on day 18 of gestation. (C). Fetal electrocardiography (FECG) was used to monitor the conditions of both the mother and the fetuses in either clipped or non-clipped uterine horns (n = 5 fetuses from at least 5 individual pregnant mice). (C) Measurement of oxygen concentration in the amniotic fluid before and after IR (p<0.01 indicated as two stars, n = 5 fetuses from at least 3 individual pregnant mice).

Mentions: Aseptic conditions were maintained all throughout the experiment. Pregnant mice were anesthesized with subcutaneous ketamine (Ketalar 500 mg Daiichi-Sankyo: 100 mg/Kg) and xylazine (ROMPUN INJ. SOLUTION 2% Bayer; 10 mg/Kg) and maintained with inhalational isoflurane (Forane AbbVie Inc.: 0.5%, 260 ml/min). Laparotomy was done to expose both uterine horns. After a 2-minute waiting period for heart rate conditions to stabilize, the uterine artery and ovarian artery were clipped (Figure 1A). A clip-release cycle consisted of 5 minutes of clipping followed by 5 minutes of release. A total of 3 clip-release cycles were undertaken during which a fetus from the clipped horn and a fetus from the non-clipped horn were continuously monitored using fetal electrocardiography (FECG) [25]–[27]. FECG in the International Patent Application Number: PCT/JP2006/316386 and Clip-release cycles in the Japanese Patent Application Number 2009/176683. In mice, reassuring fetal status was suggested by a fetal heart rate variability ranging between 120–250 beats per minute (bpm). Fetal heart rate (FHR) was noted to vary according to the fetal number. IR decreased the FHR of fetuses beginning at 30 seconds from clipping. During the second occlusion, the FHR of fetuses decreased to a minimum of 60 bpm and this was reversible after the second release. In the last release of the third cycle, complete reversal to normal occurred within 5 minutes (near 100 bpm) but this could not be achieved without significant changes in the heart rates of the mother or of the fetus of the non-clipped side. The establishment of intrauterine IR per experiment was confirmed through this data (Figure 1B).


Intrauterine ischemic reperfusion switches the fetal transcriptional pattern from HIF-1α- to P53-dependent regulation in the murine brain.

Dong Y, Ito T, Velayo C, Sato T, Iida K, Endo M, Funamoto K, Sato N, Yaegashi N, Kimura Y - PLoS ONE (2014)

An ischemic reperfusion in pregnant mice.(A) Experimental design (B) No IR treatment pregnant mice and Ischemic reperfusion (IR) mice underwent surgery on day 18 of gestation. (C). Fetal electrocardiography (FECG) was used to monitor the conditions of both the mother and the fetuses in either clipped or non-clipped uterine horns (n = 5 fetuses from at least 5 individual pregnant mice). (C) Measurement of oxygen concentration in the amniotic fluid before and after IR (p<0.01 indicated as two stars, n = 5 fetuses from at least 3 individual pregnant mice).
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4201554&req=5

pone-0110577-g001: An ischemic reperfusion in pregnant mice.(A) Experimental design (B) No IR treatment pregnant mice and Ischemic reperfusion (IR) mice underwent surgery on day 18 of gestation. (C). Fetal electrocardiography (FECG) was used to monitor the conditions of both the mother and the fetuses in either clipped or non-clipped uterine horns (n = 5 fetuses from at least 5 individual pregnant mice). (C) Measurement of oxygen concentration in the amniotic fluid before and after IR (p<0.01 indicated as two stars, n = 5 fetuses from at least 3 individual pregnant mice).
Mentions: Aseptic conditions were maintained all throughout the experiment. Pregnant mice were anesthesized with subcutaneous ketamine (Ketalar 500 mg Daiichi-Sankyo: 100 mg/Kg) and xylazine (ROMPUN INJ. SOLUTION 2% Bayer; 10 mg/Kg) and maintained with inhalational isoflurane (Forane AbbVie Inc.: 0.5%, 260 ml/min). Laparotomy was done to expose both uterine horns. After a 2-minute waiting period for heart rate conditions to stabilize, the uterine artery and ovarian artery were clipped (Figure 1A). A clip-release cycle consisted of 5 minutes of clipping followed by 5 minutes of release. A total of 3 clip-release cycles were undertaken during which a fetus from the clipped horn and a fetus from the non-clipped horn were continuously monitored using fetal electrocardiography (FECG) [25]–[27]. FECG in the International Patent Application Number: PCT/JP2006/316386 and Clip-release cycles in the Japanese Patent Application Number 2009/176683. In mice, reassuring fetal status was suggested by a fetal heart rate variability ranging between 120–250 beats per minute (bpm). Fetal heart rate (FHR) was noted to vary according to the fetal number. IR decreased the FHR of fetuses beginning at 30 seconds from clipping. During the second occlusion, the FHR of fetuses decreased to a minimum of 60 bpm and this was reversible after the second release. In the last release of the third cycle, complete reversal to normal occurred within 5 minutes (near 100 bpm) but this could not be achieved without significant changes in the heart rates of the mother or of the fetus of the non-clipped side. The establishment of intrauterine IR per experiment was confirmed through this data (Figure 1B).

Bottom Line: In the present work, pregnant mice were exposed to IR on day 18 of gestation by clipping one side of the maternal uterine horn.Interestingly, significant changes in mRNA levels for both HIF-1α and p53 were apparent and gene regulation patterns were observed to switch from a HIF-1α-dependent to a p53-dependent process.Moreover, pre-treatment with pifithrin-α, a p53 inhibitor, inhibited protein synthesis almost completely, revealing the possibility of preventing fetal brain damage by prophylactic pifithrin-α treatment.

View Article: PubMed Central - PubMed

Affiliation: Advanced Interdisciplinary Biomedical Engineering, Tohoku University Graduate School of Medicine, Sendai, Japan.

ABSTRACT
Ischemic reperfusion (IR) during the perinatal period is a known causative factor of fetal brain damage. So far, both morphologic and histologic evidence has shown that fetal brain damage can be observed only several hours to days after an IR insult has occurred. Therefore, to prevent fetal brain damage under these circumstances, a more detailed understanding of the underlying molecular mechanisms involved during an acute response to IR is necessary. In the present work, pregnant mice were exposed to IR on day 18 of gestation by clipping one side of the maternal uterine horn. Simultaneous fetal electrocardiography was performed during the procedure to verify that conditions resulting in fetal brain damage were met. Fetal brain sampling within 30 minutes after IR insult revealed molecular evidence that a fetal response was indeed triggered in the form of inhibition of the Akt-mTOR-S6 synthesis pathway. Interestingly, significant changes in mRNA levels for both HIF-1α and p53 were apparent and gene regulation patterns were observed to switch from a HIF-1α-dependent to a p53-dependent process. Moreover, pre-treatment with pifithrin-α, a p53 inhibitor, inhibited protein synthesis almost completely, revealing the possibility of preventing fetal brain damage by prophylactic pifithrin-α treatment.

Show MeSH
Related in: MedlinePlus