Studies on pathogenesis of endotoxin-induced early acute lung injury in rabbits
- VernacularTitle:内毒素致兔早期急性肺损伤机制的探讨
- Author:
Jianxin WANG
;
Hong JIANG
;
Qingliang XUE
- Publication Type:Journal Article
- Keywords:
acute lung injury;
endotoxins;
chloroquine
- From:
Medical Journal of Chinese People's Liberation Army
2006;31(8):758-761
- CountryChina
- Language:Chinese
-
Abstract:
Objective To study the role the pathogenesis of early acute lung injury (ALI) of rabbits induced by intravascular injection of endotoxin (ET) with the intervening method of Chloroquine. Methods Rabbits were randomly assigned to three groups: control group, ET group, and ET+ chloroquine group. Acute lung injury was induced by intravascular injection of ET (500μg/kg). The arterial gas analyses, leucocyte and platelet counts in peripheral blood, PLA2 activity both in serum and lung tissue, lipid peroxide (LPO) and superoxide dismutase (SOD) in lung tissue were measured. Electron microscope and light microscope were used to observe the pathological injuries in pulmonary tissue. The protective effects of chloroquine in early ALI were evaluated. Results Compared with saline controls, rabbits treated with ET displayed the early lung injuries, such as the decrease of PaO2 (P＜0.05), the decrease of leucocytes and platelets in peripheral blood, the leukocytes sequestration in lung tissue. The PLA2 activity significantly increased in ET group compared with control group and chloroquine group both in serum and pulmonary tissue. In ET group, concentration of LPO increased in lung tissue (P＜0.05), while concentration of SOD decreased (P＜0.05). Severe histopathological injuries were presented in ET group, including pulmonary edema, lung tissue haemorrhage, inflammatory cells infiltration, asphyxial membrand formation, partial pulmonary closure and emphysema.Ultrastructural changes showed both type Ⅰ and type Ⅱ epithelial cells injury in ET group, the edema of endothelial cells, interalveolar septum thickening. In chloroquine group, PaO2 didn't decrease, PLA2 activities in serum and pulmonary tissue were lower than ET group (P＜0.05, P＜0.05), while the concentration of LPO in lung tissue decreased (P＜0.01) and SOD increased significantly (P＜0.01). Pathological examination showed slight pulmonary edema, inflammatory cells infiltration were extenuated, ultrastructural examination proved that the injuries were alleviated by chloroquine compared with ET group. Conclusion Intravascular injection of ET could successfully induce the early ALI models in rabbits. Chloroquine could inhibit the PLA2 activation and reduce the oxidative injury in lung tissue. The experiment result demonstrated PLA2 activation and oxidative stress played important roles in the pathophysiological process of early ET-induced ALI in rabbits.
