[Expression NOS in acute lung injury following limb ischemia/reperfusion and its significance in rats]

To investigate the expression and role of inducible NOS (iNOS) and endothelial NOS (eNOS) in acute lung injury following limb ischemia/reperfusion (4h/4h).

Wistar rats were randomized into four groups: control group, ischemia/reperfusion (I/R) group, L-Arginine (L-Arg) pretreatment group, Aminoguanidine (AG) pretreatment group. The lung tissue of each group was subjected to assay of content of MDA, MPO, W/D and NO2-/NO3-. The expression of iNOS and eNOS was examined with immunohistological staining. The pulmonary morphologic changes were observed under microscope respectively.

The acute lung injury existed after limb ischemia/reperfusion. The eNOS downregulation and iNOS upregulation among I/R, L-Arg and AG groups were observed contrasted to the control group. There was no expressional and statistical difference of iNOS between I/R group and L-Arg group. The expression of eNOS was similar between IR and AG but iNOS expression was downregulated in AG. The parameters of MDA, MPO, W/D and NO2-/NO3- in pulmonary tissue were significantly increased in I/R groups compared with those of the control group. The parameters of L-Arg and AG pretreatment groups in comparison with those of the I/R group showed significantly difference. Based on the results of pulmonary pathology, the congestion and infiltration of inflammatory cells existed obviously in IR group. L-Arg played definite role in militating lung injury and AG might make lung injury aggravated.

The NO definite production from iNOS is possible to play a competitivly protective role in acute lung injury following limb ischemia/reperfusion and antagonist of iNOS may aggravate the lung injury.