In order to investigate radioprotective effects of interleukin-6 (IL-6) to normal tissues of irradiated tumor-bearing S180 sarcoma mice and its related mechanism

the contents of reactive oxygen species(ROS)

malondialdehyde (MDA)

activity of glutathione peroxidaes (GSH-Px) and catalase (CAT) in liver

kidney

spleen

lung

brain

marrow were determined. It was found that the content of ROS and MDA increased and the content of GSH-Px and CAT decreased in normal tissues of tumor-bearing S180 sarcoma mice under fractional total-body-irradiation (TB1). With addition of IL-6 the content of ROS and MDA was decreased and the activity of GSH-Px and CAT was increased in liver

spleen

brain

marrow

whereas there is no significant effect on the lung and kidney tissues. It can be deduced that IL-6 has some radio-protective effects to the normal tissue of tumor-bearing mice involved in fractional TBI via scavenging ROS and protecting antioxidant enzymes. As the number

affinity of IL-6 receptor and signal transfer pathway of IL-6 are changeable

the radio-protective effects of IL-6 in various tissues are different.