Introduction: Post-cardiac arrest syndrome is characterized by elevated inflammatory cytokine levels which mimics that observed in severe sepsis. The intestinal ischemia is considered an important mechanism. In the present study, we evaluated the correlation of mesenteric microcirculation and inflammatory cytokine levels (IL-6) in a rat model of CPR. Methods: Fifteen male Sprague-Dawley rats weighing 500 ± 50 kg were randomized into two groups: 1) CPR group (n=10): ventricular fibrillation (VF) was untreated for 8 mins prior to 8 mins of CPR; 2) Sham control group (n=5): a sham operation was performed without the induction of VF and CPR. Mesenteric microcirculatory blood flow was visualized by a sidestream dark-field imaging device at baseline and 2, 4, 6 and 8 hrs post-resuscitation. Microvascular blood flow index (MFI) was measured semiquantitatively. Measurements of serum IL-6 levels at the same time points were conducted using the enzyme-linked immunosorbent assay (ELISA) method. Results: Mesenteric MFI in the CPR group was significantly reduced from baseline of 1.80 ± 0.69 to 1.41 ± 0.71 at 8 hrs post-resuscitation (p<0.05 vs. baseline and sham control). Meanwhile, IL-6 levels were significantly increased compared with the sham control group (6 hrs: 252 ± 132 vs. 114 ± 78 pg/ml, p<0.05; 8 hrs: 295 ± 160 vs. 110 ± 73 pg/ml, p<0.05). There was a negative correlation between mesenteric MFI and IL-6 levels (r=-0.274, p<0.05). Conclusions: Post-resuscitation mesenteric microcirculatory dysfunction was associated with elevated IL-6 levels. These changes may contribute to the severity of post-resuscitation syndrome.
1Weil Institute of Critical Care Medicine, Rancho Mirage, CA, 2Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China, 3Keck School of Medicine of the University of Southern California, Los Angeles, CA