Objective To explore the therapeutic effect of angiotensin-converting enzyme 2( ACE2) on pulmonary edema after sea-water drowning.Methods Twenty-four Wistar rats were randomly divided into 3 groups, ie. a control group, a seawater drowning group, and an ACE2 treatment group. The rats in the seawater drowning group and the ACE2 treatment group were infused sea-water into their lungs. Then the rats in the ACE2 treatment group were intraperitoneally injected with recombinant rat ACE2. All rats were killed at the time point of 3 hours. Rat arterial blood gas was analyzed and wet /dry weight ratio of lung tissue was measured. The IL-8 content in lung tissue was measured with enzyme linked immunosorbent assay. Pathological changes of lung tissue were observed under light microscope. Results Acute lung injury induced by seawater drowning was successfully reproduced in the rats. The PaO2 in the seawater drowning group was significantly lower than that in the control group and the ACE2 treatment group [ ( 52. 34 ±2. 69) mmHg vs. ( 96. 40 ±3. 47) mm Hg and ( 64. 58 ±3. 42) mm Hg, P lt;0. 05] . The lung W/D ratio and IL-8 level in the seawater drowning group were significantly higher than those in the control group and the ACE2 treatment group ( 8. 30 ±0. 24 vs. 4. 49 ±0. 19 and 5. 65 ±0. 25, P lt; 0. 05; 1112. 2 ±40. 02 vs. 440. 39 ± 4. 06 and 858. 56 ±9. 92, P lt;0. 05) . Lung pathological examination revealed hemorrhage and hyaline membrane formation, alveolar and interstitial edema in the seawater drowning group while those changes significantly relieved in the ACE2 treatment group. Conclusion ACE2 treatment has therapeutic effects on acute lung injury induced by seawater drowning.
ObjectiveTo explore the therapeutic effect of angiotensin-converting enzyme 2 (ACE2) on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in a rat model. MethodsTwenty-four Wistar rats were randomly divided into a control group, an ALI group, and an ACE2 group.The rat ALI model was established by intravenous injection of LPS.Then the rats in the ACE2 group received intraperitoneally injection of recombinant rat ACE2 by 0.1 mg/kg immediately after LPS injection.All rats were sacrificed 2 hours later.Rat arterial blood gas was analyzed and wet/dry (W/D) weight ratio of lung tissue was measured.Concentrations of TNF-α, IL-8 and IL-1βin lung tissue homogenates were measured by ELISA.Pulmonary pathological changes were evaluated by hematoxylin-eosin stain under light microscope. ResultsALI induced by LPS was successfully established in the rats.ACE2 pretreatment markedly impoved PaO2 level of the ALI rats(P < 0.05), and decreased the lung W/D ratio(P < 0.05).The concentration of TNF-α, IL-8 and IL-1βin lung tissue homogenates were also inhibited by ACE2.And the lung histopathological changes and score were attenuated in the ACE2 group. ConclusionACE2 treatment has therapeutic effects on ALI induced by LPS.