Evaluation of apoptosis in the liver preserved by simple hypothermia using histidine-tryptophan-ketoglutarate and...

Organ ischemia is accompanied by cell death due to apoptosis. It occurs together with necrosis, which has more unfavorable consequences due to the release of cytokines that activate the inflammatory response cascade. The aim of this study was to assess the degree of apoptosis in porcine livers preserved by simple hypothermia for 12 hours using standard solutions (University of Wisconsin [UW] and histidine-tryptophan-glutarate [HTK]), and to evaluate the effect of prolactin (PRL) addition to the HTK solution.

The study was performed on the livers of Great White breed pigs, after inducing 30 minutes of warm ischemia (WIT30), followed by 30 minutes of perfusion-cooling to 4°C, and 12 hours of preservation. Livers were evaluated after preservation in Ringer's solution (control); UW (control reference fluid); HTK and HTK modified by the addition of prolactin (20 UI/L. Apoptosis was assessed in liver sections by the TdT-mediated dUTP nick-end labeling method after 12-hour preservation. We adopted a prevalence scale ranging from 0 to 3+, depending on the number of observed nuclei and apoptotic bodies (AB).

Preservation in Ringer's solution yielded AB distribution at the 1+ level, with a lack of characteristic localization resulting from necrotic lesions. Analysis of the livers preserved in the UW solution showed high, 3+ level of AB presence. For the tested HTK solution, the observed ABs localization value was 3+, whereas in the PRL-modified group it was also 3+, but with a tendency to move from zone II to cluster III, which is important for liver metabolic functions.

PRL improved the preservation properties of HTK for porcine livers by maintaining a high apoptosis level. It may stabilize cell membranes thus reducing the oncotic necrosis, promoting increased apoptosis during simple hypothermia.