Ultrastructural changes in the contralateral lung tissue following unilateral lung ischemia: an experimental study in rabbits.

Purpose: To investigate the acute ultrastructural changes that may occur in the contralateral nonischemic lung tissue after unilateral ischemia of a lung in a rabbit model.

Methods: The animals were divided into three main groups of eight; namely, a 2-h procedure group, a 4-h procedure group, and an 8-h procedure group. Each of these groups was further divided into two subgroups of four rabbits each; namely, a control group, given a sham operation without any ischemic insult, and an ischemia group, in which the main pulmonary arteries, the pulmonary veins, and the main bronchi of the left lungs were ligated after thoracotomy. Tissue samples were taken from the left and right lungs to examine the ultrastructural changes after 2, 4, and 8 h of ischemia. Each sample was given a semiquantitative histological injury score. Statistical analysis was done by the Mann-Whitney U-test.

Results: Contralateral ultrastructural damage, evident by heterochromatin in the nuclei, mitochondrial degeneration, cisternal widening of the endoplasmic reticulum, increased lipid droplets, and lysosomes, was determined by electron microscopy after unilateral lung ischemia. The contralateral lung injury was significantly correlated with the duration of ischemia.

Conclusions: Unilateral lung ischemia affected the bilateral lungs in a rabbit model. Therefore, in operations such as single-lung transplantation, pulmonectomy, or lobectomy, if the procedure is unnecessarily prolonged, the contralateral lung may be damaged, which could seriously affect the prognosis of the patient.