Korean J Thorac Cardiovasc Surg.  1999 Nov;32(11):978-983.

Leukocyte Sequestration and Free Radical-Mediated Lung Injury in Ovine Cardiopulmonary bypass Using Membrane Oxygenator

• Kim WG
• Shin YC
• Suh JW

Abstract

BACKGROUND: Complement activation with transpulmonary leukocyte sequestration is considered a main mediator leading to ischemia-reperfusion lung(I-R) injury. We studied the role of leukocytes in the formation of I-R injury in ovine cardiopulmonary bypass(CPB) model with a membrane oxygenator. MATERIAL AND METHOD: Five sheep were used. CPB circuitry consisted of a roller pump(American Optical Corp., Greenwich, CT, USA) and a membrane oxygenator(UNIVOX-IC, Bentley, Baxter Health Corp, Irvine, CA, USA). The CPB time was fixed at 120 min. Ten minutes after the start of CPB, total CPB was established. Thereafter a total CPB of 100 min was performed, followed by another 10 min of partial CPB. The CPB was discontinued and the animals were fully recovered. For measuring left and right atrial leukocyte counts, blood samples were taken before thoracotomy, 5 min and 109 in after the start of CPB, and 30 min and 120 min after weaning. C3a was measured before thoracotomy, 109 min after the start of CPB, and 30 min and 120 min after weaning. Plasma malondialdehyde(MDA) was checked before thoracotomy, 109 min after the start of CPB, and 30 min after weaning. One to two grams of lung tissue were taken for water content measurement before thoracotomy, 109 min after the start of CPB, and 30 min after weaning. Lung biopsy specimens were examined by light and electron microscopy. RESULT: Of 5 animals, 4 survived the experimental procedures. Of these, 3 animals survived on a long-term basis. No significant differences in transpulmonary gradients of leukocyte were found and no significant complement activation was expressed by C3a levels. MDA level did not show significant changes related to lung reperfusion despite an increase after the start of CPB. On both light and electron microscopic examinations, mild to moderate acute lung change was observed. Interstitial edema, leakage of erythrocytes into the alveolar space and endothelial cell swelling were the main findings. Water content of the lung showed a slight increase after the start of CPB, but there was no statistical significance.
CONCLUSION
These findings indicate that ischemia-repersusion lung injury may not be from complement activation-leukocyte sequestration but from another source of oxygen free radicals related to CPB.

Keyword

Organ preservation; Cardiopulmonary bypass; Reperfusion injury

MeSH Terms

Animals
Biopsy
Cardiopulmonary Bypass*
Complement Activation
Complement System Proteins
Edema
Endothelial Cells
Erythrocytes
Free Radicals
Leukocyte Count
Leukocytes*
Lung Injury*
Lung*
Membranes*
Microscopy, Electron
Organ Preservation
Oxygen
Oxygenators, Membrane*
Plasma
Reperfusion
Reperfusion Injury
Sheep
Thoracotomy
Weaning
Complement System Proteins
Free Radicals
Oxygen