Expressions of COX-2 in the lung tissue of traumatic hemorrhagic shock rats and their correlations to secondary lung injury in dry heat environment of desert

LI Rui; XIE Zhi; LIU Jiang-wei; QIAN Jian-hui; QIAN Ruo-yun; ZHANG Qiong; YANG Xiang-xin; YANG Fan

Abstract：Objective To study the relationship among the changes of lung tissue malondialdehyde ( MDA) concentration ,total superoxide dismutase ( T-SOD) activity and COX-2 mRNA expression levels of traumatic hemor-rhagic shock rats and their correlations to the secondary lung injury in the dry heat environment of desert .Methods Totally 140 male SD rats with traumatic hemorrhagic shock were randomly divided into the dry heat environment group and the normal temperature environment group .Each group was randomly divided into 7 subgroups:the con-trol group,0 hour group,0.5 hours group,1 hour group,1.5 hours group,2 hours group,3 hours group,10 rats in each subgroup .After the establishment of traumatic hemorrhagic shock rat models in each environment ,at the corre-sponding time points ,specimens from the bronchoalveolar lavage fluid ( BALF) and lung tissue were harvested .The optical microscopy was performed to examine the pathological changes in lung ,the total protein of BALF was meas-ured,the concentrations of MDA ,T-SOD and COX-2 mRNA in lung tissue were detected .Results The pathologi-cal injury was more serious and the histopathology score for lung injury was higher in the dry heat environment group than in the corresponding normal temperature environment group .The MDA concentration at each time point in the dry heat environment group was higher than that of the corresponding normal temperature environment group .How-ever,the T-SOD activity was lower than that of the normal temperature environment group .The expressions of COX-2 mRNA were higher in dry heat environment group than the corresponding normal temperature environment group . COX-2 mRNA expression reached its peak at 1.5 hours in the dry heat environment group ,however,COX-2 mRNA reached its peak at 2 hours in the normal temperature environment group .The expressions of COX-2 mRNA were positively correlated with lung injury scores ( P<0.05 ) . Conclusion The secondary lung injuries of traumatic hemorrhagic shock rats are more serious in dry heat environment than in normal temperature environment .MDA and T-SOD are important index reflecting secondary lung injury .COX-2 mRNA plays an important role in the secondary injury of traumatic hemorrhagic shock rats in the dry heat environment of desert .COX-2 may be an effective target in the treatment of traumatic hemorrhagic shock .