The Effect Of Captopril And Losartan On Paraquat-induced Pulmonary Fibrosis And PlGF Expression In The Lungs Of Rats

Objective To investigate the dynamic expression of placenta growth factor( PlGF) in the lungs and its role in paraquat-induced pulmonary fibrosis and to evaluate the effect of ACEI captopril and AT (1)-receptor blocker losartan on paraquat-induced pulmonary fibrosis.Methods 84 adult healthy female Sprague-Dawley(SD) rats were randomly divided into four groups of different treatments designated as: Control, PQ alone (PQ), captopril treatment(PQ+CPT), losartan treatment(PQ+Los). Each group was divided into three subgroups of seven animals each. The animals were killed at either 7, 14 or 28 days after PQ administration. The rats in PQ group, treatment group (PQ+CPT, PQ+Los) were treated intragastrically(ig) with PQ (40mg/kg) and the rats in control group were treated with the same dose of saline at the beginning of the experiment. The treatment group (PQ+CPT, PQ+Los) received Captopril (60mg/kg; ig) or Losartan (10mg/kg; ig) once a day respectively after PQ administration and the other two groups received saline. At the given timepoint, animals were sacrificed and lungs were harvested. The body weight and lung wet weight of rats were measured, and the weight gain and lung index of rats in each group were compared. A semiquantitative assay of histological examination, MPO and hydroxyproline in lung tissues were used to determine the severity of alveolitis and fibrosis. RT-PCR and immunohistochemistry were used to detect the mRNA and protein expression of PlGF.Results Rat body weight evidently decreased while the indices of lung and MPO, hydroxyproline contents in lung tissue were significantly increased after PQ administration. Inflammatory cell infiltration and fibrotic scores were more prominent in the model group compared to the control group. Captopril, losartan apparently attenuated the degree of lung injury and pulmonary fibrosis. Further study showed...