Direct Peritoneal Resuscitation Reduces Lung Injury and Caspase 8 Activity in Brain Death*

Abstract

Background: Acute brain death (ABD) is associated with inflammation and lung injury. Direct peritoneal resuscitation (DPR) improves blood flow to the vital organs after ABD. DPR reduces lung injury, but the mechanism for this is unknown. Methods: Male Sprague-Dawley rats were randomized to five groups (n = 8/group): (1) Sham (no ABD); (2) Targeted intravenous fluid (TIVF) (ABD plus enough IVF to maintain a MAP of 80 mmHg) at 2 hours post-resuscitation (RES); (3) ABD + TIVF + DPR (TIVF and 30 cc intraperitoneal 2.5% Delflex) at 2 hours post-RES; (4) ABD + TIVF at 4 hours post-RES; and (5) ABD + TIVF + DPR at 4 hours post-RES. Messenger RNA (mRNA) levels were measured using Qiagen qRT PCR. Protein levels were assessed using quantitative ELISAs and the Luminex MagPix system. Results: Use of DPR caused 5.8-fold downregulation of mRNA expression for TNF-α and 2.7-fold decrease for the TNF receptor compared to TIVF alone. Caspase 8 mRNA was also downregulated. Protein levels for TNF-α, TNF receptor, caspase 8, NFκB, and NFκB inhibitor kinase, which promotes dissociation of NFκB inhibitor, were reduced by DPR. Cell death markers M30 and M65 were also decreased with DPR. Conclusions: Use of DPR caused changes in the expression of multiple mRNAs and proteins in the caspase 8 apoptotic pathway. These data represent a mechanism through which DPR exerts its beneficial effects within the lung tissue.