ACUTE RELEASE OF CYTOKINES IS PROPORTIONAL TO TISSUE-INJURY INDUCED BY SURGICAL TRAUMA AND SHOCK IN RATS

Cytokines are important mediators of the inflammatory reaction and microvascular injury after trauma and tissue ischemia. The plasma activity of a cytokine reflects the net effect of positive and negative signals. We examined the sequential serum activity of IL-1, Il-2, Il-6, and TNF in a severe model of splanchnic artery occlusion (SAO) shock induced in rats by total occlusion of the superior mesenteric and the celiac arteries for 40 min. A control group with negligible surgical intervention and two sham-shock groups, one with minor operation and another with major surgery employed in SAO rats, both without vascular occlusion, were also studied. No IL-1 activity was detected throughout the 190-min experimental protocol in any of the groups. Low activity of IL-2 was measured only in SAO rats (approximately 1 U/ml at the peak). We found graded increases in serum TNF and IL-6 activities which were proportional to the surgical trauma and were highest in SAO rats (Il-6 up to 30 U/ml, P < 0.01 from both sham groups; TNF, 2500 pg/ml 30 min after reperfusion, P < 0.01 from both sham groups). These data further support the role played by cytokines in the early mediation of surgical trauma and shock.