Multi-organ inflammation after hepatic cryoablation in BALB/c mice

Background. There is increasing evidence that injury to the liver can precipitate or exaggerate lung injury. We have previously shown that hepatic cryoablation (cryo) causes activation of nuclear factor (NF)-κB, cytokinemia (tumor necrosis factor-α, Mouse Macrophage Inflammatory Protein-2 [MIP-2]), and lung inflammation in transgenic HLL (5′HIV-LTR-Luciferase gene) mice and in Sprague-Dawley rats. It has been reported that BALB/c mice are susceptible to traumatic injury and are active immune responders. We tested whether activation of NF-κB and the development of multiple-organ inflammation in response to hepatic injury from 35% cryo were demonstrable in the BALB/c mouse. Methods. BALB/c mice (n = 9) were anesthetized, and midline laparotomy was performed. Cryoablation was performed with careful isolation of adjacent structures to avoid inadvertent organ injury to the gastrointestinal tract. A freeze-thaw cycle of the left lobe of the liver was induced, encompassing approximately 35% (by weight). Animals were sacrificed at 1, 2, 4, and 24 h after cryoablation. Serum was collected via IVC puncture and liver, lungs, and kidneys were harvested and freeze-clamped. Two animals were sacrificed without undergoing cryo surgery to serve as a baseline control. NF-κB activity was monitored by electrophoretic mobility shift assays. MIP-2 levels and Mouse KC levels from tissue and serum were measured using enzyme-linked immunosorbent assay. Organs were submitted for histological review. We characterized lung inflammation induced by cryosurgery by measuring total and differential cell counts in lung lavage fluid 4 h after hepatic cryoablation. Results. After cryo, NF-κB activation was demonstrated in the 1, 2, and 4-h time points by electrophoretic mobility shift assay in the liver and lungs. Mouse KC and MIP-2 levels increased from baseline, peaked at the 4-h time point, and returned to baseline after 24 h in both liver and lung. Lung lavage 4 h after cryoablation showed increased total cells and neutrophilic lung inflammation. Conclusions. BALB/c mice demonstrate evidence of multi-organ inflammation in response to 35% hepatic cryo. These data demonstrate that this model provides for assessment of liver-mediated multi-system inflammation after direct liver injury.