Changes in mRNA expression patterns for cytokines in blood leukocytes of a rat tourniquet model.

We examined changes in mRNA expression patterns for proinflammatory cytokines and growth factors in blood samples after application of a tourniquet to the rat hind limb. Slight upregulations of interferon (IFN)-gamma, macrophage colony-stimulating factor (M-CSF) and transforming growth factor (TGF)-beta1 mRNA began at 2h after tourniquet application and were short-lived. The levels of activating transcription factor (ATF)-3, a stress-inducible gene, had increased at 1h after tourniquet application. No significant expression of interleukin (IL)-6 mRNA was observed in most samples. There were no significant temporal changes in the levels of IL-1beta, cardiotrophin (CT)-1 mRNA compared to the control levels, but, downregulation of gp130, a receptor of the IL-6 family, began at 1h after tourniquet application. Nerve growth factor (NGF) mRNA gradually increased and reached a significantly high level at 4h after application of the tourniquet. Gene expression induction in blood leukocytes occurred soon after application of the tourniquet and was short-lived. The transient mRNA expressions probably trigger secondary events that may be beneficial to wound repair and regeneration.