Resuscitation-induced pulmonary apoptosis and intracellular adhesion molecule-1 expression in rats are attenuated by the use of Ketone Ringer's solution.

BACKGROUND

Resuscitation with Lactated Ringer's solution after hemorrhagic shock in rats has been shown to cause early cellular injury in the lung. We hypothesized that the use of energy substrates, such as ketone bodies, in the resuscitation fluids would protect against this injury. As markers of cellular injury we measured the induction of apoptotic cell death and the expression of Intracellular Adhesion Molecule-1 (ICAM-1).

STUDY DESIGN

Male Sprague Dawley rats (n = 35) under inhaled isoflurane anesthesia had placement of femoral arterial and venous catheters. A three-stage hemorrhage model was used for this experiment. There was an initial hemorrhage of 27 mL/kg for 10 minutes. During the next 75 minutes another 8 mL/kg of blood was withdrawn at a steady rate. The resuscitation fluids were then infused for 45 minutes during which the third continuous hemorrhage of 8 mL/kg was performed. The animals were randomized to five groups: 1) sham hemorrhage (n = 6); 2) sham resuscitation (n = 7); 3) Lactated Ringer's resuscitation, three times the volume of shed blood (n = 8); 4) Ketone Ringer's (containing 28 mEq/L of beta-hydroxybutyrate) resuscitation, three times the volume of shed blood (n = 7); and 5) plasma resuscitation, volume equal to shed blood (n = 7). The animals were sacrificed 1 hour after resuscitation and lungs were harvested. Western blot technique was used for the determination of proapoptotic protein (bax), antiapoptotic protein (bcl-2), apoptotic fragments of poly ADP-ribose polymerase, and ICAM-1. Sections of lung were also subjected to immunostaining using antibodies to bax and ICAM-1 proteins (reported as number of positive cells/mm2).

RESULTS

Lactated Ringer's resuscitation caused a significant increase in pulmonary apoptosis and ICAM-1 expression compared with the sham hemorrhage group. Animals resuscitated with Ketone Ringer's solution and plasma did not show this injury pattern.

CONCLUSIONS

Substitution of lactate with ketone bodies in the resuscitation fluid attenuates the expression of cellular injury markers in the lung.