The Expression Of α1-antitrypsin MRNA Of Lung Tissues In Rats Acute Lung Injury Induced By Oleic Aicd

OBJECTIVE To observe the expression ofα1-antitrypsin mRNA in lung tissues of acute lung injury induced by oleic aicd in SD rats,and to investigate the function ofα1-antitrypsin mRNA expressed in local lung tissues of rats in acute lung injury.METHODS Models of acute lung injury in rats were induced by oleic aicd(oleic aicd,0.20ml/kg,iv). A total of 32 SD rats were randomly divided into 4 groups (n=8 each)as follows:the control group , the acute lung injury groups induced by oleic aicd ,4 hours group(group A), 8 hours group (group B)and 16 hours group(group D).We infused normal saline via the tail vein for control group,and oleic aicd for group A , group B and group D.The rats were sacrificed by bleeding at 4h,8 h and 16h after intravenous oleic aicd administration,and at 4h after intravenous normal saline administration.As the meantime arterial blood gases were analysed.Then the lungs were removed,the middle lobes of the left lungs were obtained forα1-antitrypsin mRNA analyse by RT-PCR and the lower lobes of the left lungs for detecting the ratio of wet to dry as well as the top lobes for pathological section analyzing .Cells in right bronchoalvenar lavage fluid (BALF) were counted and the percentage of PMN were classified in sediment film,and albumin concentration of BALF were measured.RESULT The expression ofα1-antitrypsin mRNA which was very low in control group,however significantly increased in ALI group induced by oleic aicd at 4 hours(P<0.01);the increase inα1-antitrypsin mRNA was linear from 4 h until 16 h after intravenous oleic aicd administration ;and reached peak at 16 hours (P<0.01). As compared to the control grounp , the structures of pulmonary alveoli in group A,B and D were demolished,and infiltration of polymorphologic cells , widen alveolar wall and local hemorrhage in alveolar wall were found. The amount of PMN and albumin in BALF of grounp A,B and D was significantly increased(P<0.01). Compared with control grounp,the arterial blood oxygen pressures decreased significantly in group A,B and D(P<0.01).The ratio of wet to dry in group B and D were significantly higher than those in group A and control grounp(P<0.01). CONCLUSIONS The expression ofα1-antitrypsin mRNA in local lung tissues of rats in ALI induced by oleic aicd,was significantly increased.α1-antitrypsin mRNA which were expressed in local lung tissues participated in the pathogenesis of acute lung injury.