Objective To investigate the expressions of sphingosine 1-phosphate (S1P) and S1P G-protein-coupled receptor 1 (S1PR1) in pulmonary ischemia reperfusion injury （PIRI) tissues and explore their relationship．Methods The model of PIRI was established in vivo male C57BL/6 mice (n=8). The left pulmonary hilum was occluded for 30 min with a microvascular clamp through a left thoracotomy. Reperfusion began with removal of the clamp. Normal group (n=8) and sham group (n=8) were set as control. The hematoxylin and eosin (HE) staining of ultrastructural changes and wet-to-dry mass ratio in lung tissues were measured for judging the succeed model. The mRNA expressions of sphingosine kinase 1 (SphK1) and S1PR1 were determined by real-time PCR, and ELISA was used to detect the concentrations of S1P and S1PR1 in the lung tissues. Results The mRNA expressions of SphK1, S1PR1 and the concentrations of S1P and S1PR1 and wet-to-dry mass ratio of the lung tissues in ischemia-reperfusion mice were higher than those normal mice and sham operation mice (P
