See the published version of this preprint at Intensive Care Medicine Experimental.
This is a preprint, a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
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Pierre Eyenga
Université Claude Bernard Lyon-Centre Hospitalier de Sens
Corresponding Author
ORCiD: https://orcid.org/0000-0002-3440-1481
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background: To describe the effect of mechanical ventilation on diaphragm mitochondrial oxygen consumption, ATP production, reactive oxygen species (ROS) generation, and cytochrome-c oxidase activity and content, and their relationship to diaphragm strength in an experimental model of sepsis.
Methods: A cecal ligation and puncture (CLP) protocol was performed in 12 rats while 12 controls underwent sham-operation. Half of the rats in each group were paralyzed and mechanically ventilated. We performed blood gas analysis and lactic acid assays 6 hours after surgery. Afterwards, we measured diaphragm strength and mitochondrial oxygen consumption, ATP and ROS generation, and cytochrome-c oxidase activity. We also measured malondialdehyde (MDA) content as an index of lipid peroxidation, and mRNA expression of the pro-inflammatory interleukin-1β (IL-1β) in diaphragms.
Results: CLP rats showed severe hypotension, metabolic acidosis, and upregulation of diaphragm IL-1β mRNA expression. Compared to sham controls, spontaneously breathing CLP rats showed lower diaphragm force and increased susceptibility to fatigue, along with depressed mitochondrial oxygen consumption and ATP production and cytochrome-c oxidase activity. These rats also showed increased mitochondrial ROS generation and MDA content. Mechanical ventilation markedly restored mitochondrial oxygen consumption and ATP production in CLP rats; lowered mitochondrial ROS production by the complex 3; and preserved cytochrome-c oxidase activity.
Conclusion: In an experimental model of sepsis, early initiation of mechanical ventilation restores diaphragm mitochondrial function.
Keywords
mechanical ventilation, reactive oxygen species (ROS), cytochrome-c, sepsis
Figure 1
Figure 2
Figure 3
Figure 4
This is a list of supplementary files associated with this preprint. Click to download.
- Table1Eyengaetalshortterm.doc
Table 1: Arterial blood gases (pH, PaO2, PaCO2, HCO3-) and plasma lactic acid measured at the end of the procedure in control, sepsis, MV-sepsis and MV-control groups. Data are means ±SEM from 6 animals per group. Data are means ±SEM from 6 animals per group. * p<0.05 sepsis versus control; † p<0.05 sepsis versus MV-control; ‡ p < 0.05 MV-sepsis versus control and § p<0.05 MV-sepsis versus MV control
- Table2Eyengaetalshortterm.doc
Table 2. Mitochondrial oxygen consumption and ATP synthesis Measures were performed on diaphragm mitochondria from rats of the four following groups: spontaneously breathing controls (Control), spontaneously breathing sepsis group (Sepsis), mechanically ventilated control group (MV-Control) and a mechanically ventilated sepsis group (MV-Sepsis). Mitochondria were energized with succinate as respiratory substrate in the presence of rotenone State 3 phosphorylating respiration as well as ATP production were measured at 100 µM of exogenous ADP. State 4 respiration was obtained by inhibiting the ATP synthase with 3µg/ml of oligomycin.. Data are means ±SEM from 6 animals per group. * p<0.05 sepsis versus Control; † p<0.05 sepsis versus MV-Control; £ p<0.05 sepsis versus MV-sepsis.
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CURRENT STATUS: Published
View the published article at Intensive Care Medicine Experimental.
Version 1
Posted 22 Oct, 2020
No community comments so far
Reviewer #2 agreed
On 19 Jan, 2021
Review #2 received
Received 19 Jan, 2021
Editorial decision: Major revision
On 19 Jan, 2021
Review #1 received
Received 16 Jan, 2021
Reviewer #1 agreed
On 26 Dec, 2020
Reviewers invited
Invitations sent on 01 Nov, 2020
Editor assigned
On 23 Oct, 2020
Editor invited
On 22 Oct, 2020
Submission checks complete
On 19 Oct, 2020
First submitted
On 18 Oct, 2020
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PDF Downloads: ...
HTML Views: ...
Subject Areas
Internal Medicine
Learn more about our company.
See the published version of this preprint at Intensive Care Medicine Experimental.
This is a preprint, a preliminary version of a manuscript that has not completed peer review at a journal. Research Square does not conduct peer review prior to posting preprints. The posting of a preprint on this server should not be interpreted as an endorsement of its validity or suitability for dissemination as established information or for guiding clinical practice.
Learn more about In Review
Research
Pierre Eyenga
Université Claude Bernard Lyon-Centre Hospitalier de Sens
Corresponding Author
ORCiD: https://orcid.org/0000-0002-3440-1481
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
Peer Review Timeline
CURRENT STATUS: Published
View the published article at Intensive Care Medicine Experimental.
Version 1
Posted 22 Oct, 2020
No community comments so far
Reviewer #2 agreed
On 19 Jan, 2021
Review #2 received
Received 19 Jan, 2021
Editorial decision: Major revision
On 19 Jan, 2021
Review #1 received
Received 16 Jan, 2021
Reviewer #1 agreed
On 26 Dec, 2020
Reviewers invited
Invitations sent on 01 Nov, 2020
Editor assigned
On 23 Oct, 2020
Editor invited
On 22 Oct, 2020
Submission checks complete
On 19 Oct, 2020
First submitted
On 18 Oct, 2020
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
Subject Areas
Internal Medicine
License:
This work is licensed under a CC BY 4.0 License. Read Full License
View the published article at Intensive Care Medicine Experimental.
Background: To describe the effect of mechanical ventilation on diaphragm mitochondrial oxygen consumption, ATP production, reactive oxygen species (ROS) generation, and cytochrome-c oxidase activity and content, and their relationship to diaphragm strength in an experimental model of sepsis.
Methods: A cecal ligation and puncture (CLP) protocol was performed in 12 rats while 12 controls underwent sham-operation. Half of the rats in each group were paralyzed and mechanically ventilated. We performed blood gas analysis and lactic acid assays 6 hours after surgery. Afterwards, we measured diaphragm strength and mitochondrial oxygen consumption, ATP and ROS generation, and cytochrome-c oxidase activity. We also measured malondialdehyde (MDA) content as an index of lipid peroxidation, and mRNA expression of the pro-inflammatory interleukin-1β (IL-1β) in diaphragms.
Results: CLP rats showed severe hypotension, metabolic acidosis, and upregulation of diaphragm IL-1β mRNA expression. Compared to sham controls, spontaneously breathing CLP rats showed lower diaphragm force and increased susceptibility to fatigue, along with depressed mitochondrial oxygen consumption and ATP production and cytochrome-c oxidase activity. These rats also showed increased mitochondrial ROS generation and MDA content. Mechanical ventilation markedly restored mitochondrial oxygen consumption and ATP production in CLP rats; lowered mitochondrial ROS production by the complex 3; and preserved cytochrome-c oxidase activity.
Conclusion: In an experimental model of sepsis, early initiation of mechanical ventilation restores diaphragm mitochondrial function.
Figure 1
Figure 2
Figure 3
Figure 4
This is a list of supplementary files associated with this preprint. Click to download.
- Table1Eyengaetalshortterm.doc
Table 1: Arterial blood gases (pH, PaO2, PaCO2, HCO3-) and plasma lactic acid measured at the end of the procedure in control, sepsis, MV-sepsis and MV-control groups. Data are means ±SEM from 6 animals per group. Data are means ±SEM from 6 animals per group. * p<0.05 sepsis versus control; † p<0.05 sepsis versus MV-control; ‡ p < 0.05 MV-sepsis versus control and § p<0.05 MV-sepsis versus MV control
- Table2Eyengaetalshortterm.doc
Table 2. Mitochondrial oxygen consumption and ATP synthesis Measures were performed on diaphragm mitochondria from rats of the four following groups: spontaneously breathing controls (Control), spontaneously breathing sepsis group (Sepsis), mechanically ventilated control group (MV-Control) and a mechanically ventilated sepsis group (MV-Sepsis). Mitochondria were energized with succinate as respiratory substrate in the presence of rotenone State 3 phosphorylating respiration as well as ATP production were measured at 100 µM of exogenous ADP. State 4 respiration was obtained by inhibiting the ATP synthase with 3µg/ml of oligomycin.. Data are means ±SEM from 6 animals per group. * p<0.05 sepsis versus Control; † p<0.05 sepsis versus MV-Control; £ p<0.05 sepsis versus MV-sepsis.
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