Fig 1.
Experimental outline of the study.
Rats were randomly assigned to 3 donor groups: 1) control (immediate sacrifice), 2) fast brain death (BD) induction (intracranial pressure (ICP) increase over 1 min) or 3) slow BD induction (ICP increase over 30 min). Rats subjected to BD were sacrificed at 4 different time points: 0.5 hours, 1 hour, 2 hours and 4 hours after BD induction. Figure created in the Mind the Graph platform: www.mindthegraph.com.
Table 1.
RT-qPCR primers.
Fig 2.
Rats were subjected to fast brain death (BD) induction (intracranial pressure (ICP) increase over 1 min) versus slow BD induction (ICP increase over 30 min). Expansion of the Fogarty catheter and induction of BD was finished at time point zero in both models. After BD was induced, all animals were stabilized above a mean arterial pressure of 80 mmHg for 0.5–4 hours, of which the first 30 min are presented in this figure. Values are depicted as mean. Data displayed in the grey area are significant between groups, as indicated by the asterisk: * p<0.05. FM–fast BD induction model, expansion of the Fogarty catheter over 1 min; SM–slow BD induction model, expansion of the Fogarty catheter over 30 min.
Fig 3.
Inotropic support and heart rate.
Rats were subjected to fast brain death (BD) induction (intracranial pressure (ICP) increase over 1 min) versus slow BD induction (ICP increase over 30 min) and subsequently stabilized for 0.5–4 hours on a mean arterial pressure of > 80 mmHg. (A) Required noradrenalin administration for hemodynamic stabilization. (B) Heart rate of brain-dead rats during the BD stabilization period. Values are presented as mean ± SEM. Asterisks denote significant differences between the two BD models per time point: * p<0.05, ** p<0.01. X-axis 0.5–4hours–brain-dead group with period of ventilation and hemodynamic stabilization time; BL–baseline measurement before BD induction; Control–immediately sacrificed without intervention; FM–fast BD induction model, expansion of the Fogarty catheter over 1 min; SM–slow BD induction model, expansion of the Fogarty catheter over 30 min.
Fig 4.
Heart muscle injury markers CK-MB and troponin.
Rats were subjected to fast brain death (BD) induction (intracranial pressure (ICP) increase over 1 min) versus slow BD induction (ICP increase over 30 min) and subsequently stabilized for 0.5–4 hours on a mean arterial pressure of > 80 mmHg. (A) Plasma CK-MB levels and (B) plasma troponin levels of brain-dead rats and controls. Values are presented as mean ± SEM. Asterisks denote significant differences between the two BD models per time point: *** p<0.001. X-axis 0.5–4 hours–brain-dead group with period of ventilation and hemodynamic stabilization time; BL–baseline measurement before BD induction; CK-MB–Creatine kinase (myocardium); Control–immediately sacrificed without intervention; FM–fast BD induction model, expansion of the Fogarty catheter over 1 min; SM–slow BD induction model, expansion of the Fogarty catheter over 30 min.
Fig 5.
Histological lung injury score.
Rats were subjected to fast brain death (BD) induction (intracranial pressure (ICP) increase over 1 min) versus slow BD induction (ICP increase over 30 min). Lungs were procured after 0.5–4 hours of donor stabilization and histological lung injury scores were assessed. All values are presented as mean. Asterisks denote significant differences between the two BD models per time point: * p<0.05. ‘#’-symbols indicate significant differences compared to controls. X-axis 0.5–4 hours–brain-dead group with period of ventilation and hemodynamic stabilization time; Control–immediately sacrificed without intervention; FM—fast BD induction model, expansion of the Fogarty catheter over 1 min; SM—slow BD induction model, expansion of the Fogarty catheter over 30 min.
Fig 6.
Rats were subjected to fast brain death (BD) induction (intracranial pressure (ICP) increase over 1 min) versus slow BD induction (ICP increase over 30 min). Subsequently, rats were hemodynamically stabilized and ventilated for 0.5–4 hours and pulmonary airway pressures were noted. Values are presented as mean ± SEM. X-axis 0.5–4hours–brain-dead group with period of ventilation and hemodynamic stabilization time; BL–baseline measurement before BD induction; FM–fast BD induction model, expansion of the Fogarty catheter over 1 min; SM–slow BD induction model, expansion of the Fogarty catheter over 30 min.
Fig 7.
Pro-inflammatory gene expressions.
Rats were subjected to fast brain death (BD) induction (intracranial pressure (ICP) increase over 1 min) versus slow BD induction (ICP increase over 30 min). Lungs were procured after 0.5–4 hours of donor stabilization and the following gene expression levels for pro-inflammatory cytokines were assessed by means of RT-qPCR: (A) TNF-α, (B) IL-6, (C) IL-8-like CINC-1, (D) MCP-1, (E) VCAM-1 and (F) C3. Data are shown as expression relative to housekeeping genes PPIA, ELf2b1 and β-actin. Values are presented as mean ± SEM. Asterisks denote significant differences between the two BD models per time point: * p<0.05. ‘#’-symbols indicate significant differences compared to controls. X-axis 0.5–4hours–brain-dead group with period of ventilation and hemodynamic stabilization time; Control–immediately sacrificed without intervention; FM–fast BD induction model, expansion of the Fogarty catheter over 1 min; SM–slow BD induction model, expansion of the Fogarty catheter over 30 min.
Fig 8.
Infiltration of activated neutrophils.
Rats were subjected to fast brain death (BD) induction (intracranial pressure (ICP) increase over 1 min) versus slow BD induction (ICP increase over 30 min). Lungs procured after 4 hours of donor stabilization were stained for myeloperoxidase (MPO) to assess infiltration of activated neutrophils. (A) Quantification of neutrophils as depicted by MPO staining. (B-D) Representative MPO-stained lung slides of controls and rats subjected to fast or slow BD induction. Values are presented as mean ± SEM. ‘#’-symbols indicate significant differences compared to controls. Control–immediately sacrificed without intervention; FM—fast BD induction model, expansion of the Fogarty catheter over 1 min; SM—slow BD induction model, expansion of the Fogarty catheter over 30 min.