BACKGROUND:: Endothelin-1 is the strongest vasoconstrictor substance in vivo. To study the changes of endothelin-1 in limb ischemia preconditioning against hepatic injury following limb ischemia reperfusion in rats may help us to evaluate the protective effect of limb ischemia preconditioning on hepatic injury from the aspect of the hepatic microcirculation. OBJECTIVE:: To evaluate the changes of endothelin-1 in the protective effect of limb ischemia preconditioning on hepatic injury following hind limbs ischemia reperfusion in rats. METHODS:: Male Wistar rats were divided into three groups (n=8): control group, limb ischemia-reperfusion group and limb ischemia preconditioning group. The rat in the limb ischemia-reperfusion group were performed with pre-blocking pairs of hind limb blood flow for 5 minutes with rubber, and then restored the perfusion for 5 minutes, repeated the ischemic preconditioning for four times. In the limb ischemia-reperfusion group and limb ischemia preconditioning group, the rat hind limb roots were ligated by rubber band, the blood flow was released after blocked for 4 hours, and then the blood flow perfusion was restored for 4 hours to prepare the limb ischemia-reperfusion model. The rats were infused with saline through left external jugular vein catheterization at 20 minutes before reperfusion. In the control group, the rat hind limbs were loosely circled with the rubber band but not to block the blood flow, and the following procedures were same to the operation in the limb ischemia-reperfusion group and limb ischemia preconditioning group. RESULTS AND CONCLUSION:: The levels of endothelin-1, hyaluronic acid (HA), malondialdehyde (MDA), alanine transaminase (ALT) and aspartate transaminase (AST) in plasma and the contents of endothelin-1, MDA and myeloperoxide (MPO) in liver tissue were increased following LIR (P < 0.05); Compared with the limb ischemia-reperfusion group, the levels of endothelin-1, HA, MDA, ALT and AST in plasma and the contents of endothelin-1, HA, MDA and MPO in liver tissue were significantly decreased (P > 0.05) in the limb ischemia preconditioning group. The results of the light microscope clued that the hepatic cells swelling and the hepatic funiculus were irregular in the limb ischemia-reperfusion group while the liver injury were alleviated in the limb ischemia preconditioning group. The protection effect of limb ischemia preconditioning on hepatic injury following limbs ischemia reperfusion in rats may relate to the improvement of microcirculation in the liver by restraining the vasoconstrictive action of endothelin-1, which is perhaps related to improving the aggregation of neutrophil and alleviating the damage of the lipid peroxidation following the low content of endothelin-1.Zhao LJ, Zhao JQ, Yang BS, Zhang JY. Changes of endothelin-1 in the protective effect of limb ischemia preconditioning on hepatic injury following limb ischemia reperfusion in rats. Zhongguo Zuzhi Gongcheng Yanjiu. 2012;16(31): 5843-5847. [http://www.crter.cn http://en.zglckf.com]