【Objective】To investigate the mechanism of paclitaxel-induced lung injury and the preventive role of parecoxib in rats. 【Methods】 28 Wistar rats were randomly assigned into four groups: Control group

Paclitaxel group

Paclitaxe+Parecoxib group

and Parecoxib group. The changes of pulmonary permeability

gas exchange of alveolar capillary membrane and pathological section were examined. Inflammatory cytokine in lung tissue and the content of COX-2

protein expression of tight junction were detected. 【Results】 Compared with the Control group

the Pac group has a significant increase in COX-2 expression

ICAM-1

neutrophils counts and decrease in ZO-1

Claudin-4 protein in lung tissue. Pulmonary permeability in Paclitaxel group was increased and gas exchange dysfunction developed. There were no statistical differences among Paclitaxe+Parecoxib group

Parecoxib group and Control group. 【Conclusion】 Paclitaxel chemotherapy injury alveolar capillary barrier in rats. The possible mechanism was that Paclitaxel can cause Cox-2 overexpression

which activated lung inflammatory reaction and damaged the tight junction protein of alveolar capillary membrane. However

the Cox-2 specific inhibitor parecoxib can protect lung from these injuries.