An Experimental Study Of Preventative Effect Of ACEI On Chemical-induced ARDS In Rats

Objective: In order to assess the preventation utility of ACEI-CPT in Wistar rats with ARDS induced by oleic acid.we observed the changes in ratio of wet-to-dry lung weightjung coefficient,lung pathologic, meanwiile, examined the blood ACE, AII, ET-1 contents and lung microstructural changes it different period after injection of oleic acid, explored the possible mechanism of ACEI in the prevention of ARDS.Methods: 36 healthy Wistar rats were randcmly divided into three group, in mean while, each group was divided into two subset by the different time in which rats were killed, respectively.(n=6).1.Sham operated group: which were administrated with 10% glucose injection(2ml/kg) abdomently. One hour later, w ire narcotized with Urethane, then,one side femoral vein was separated. And the normal saline(0.1 ml/kg) was injected into.2.ARDS group:which were administrated with same dosage of 10% glucose injection abdomently. One hour later, were narcotized and received oleic acid(0.1ml/kg) by same way.3.CPT treatment group:which were administrated abdomently with attenuated CPT injection 2ml/kg(2.5mg/kg). one hour later, sarre dosage of oleic acid was injected through one side femoral vein by same wayAll rats were killed 3h,6h after operation, respectively. The blood in the left ventricle was taken out completely. And was infused into tube, the plasma or serum was spearted out to be examined the contents of ACE, AII, ET-1. The left and right lung tissues were cut off and weighed. The right part was desiccated and weighed again, the left part was prepared to be observed under microscope and electronic microscope. ResultS: 1.the right lung W/D.lung coefficient and the blood ACEx AII, ET-1 contents inARDS group were markedly increased than that in sham operation group. The different was quite significant (P < 0.05).and the difference between the CPT treatment group and ARDS group was also quite significant(P < 0.05) the correlation between levels of ACE, AII, ET-1 and corresponding lung coefficient was significant(P < 0.05).2.In ARDS group .pulmonary interstitial and alveolar edema. Stasis and embolism of blood in capillary,microatelectasis and massive alveolar collapse, hyaline membrane in some alveolar cavity.while in CPT treatment group,the change were slight and alveolar collapse was unobvious under light microscope.3.Ultramicrostucte in ARDS group showed broaden of alveolar septa, edema and necrosis of type I cell, evident evacuation of type II cellular lamellar body.while in CPT treatment group, change of evacuation was slight.Conclusions:1.In early stage on ARDS,the blood ACE, AII, ET-1 contents correlate with lung coefficient,can reflect the degree of damaged lung t ssue.2.Administrate inhibitior of angiotensin converting enzyme captopril can restrain ACE, AII, ET-1 from rising ,reduce lung edema and alveolar collapse.3.ACEI-CPT have certain good protective effect on rats with ARDS.