Objective      To investigate the differential expressions of microRNAs (miRNAs) in pulmonary tissues of rats with advanced pulmonary hypertension (PH)

and to predict the target genes regulating miRNA differential expressions.       Methods      Twenty male SD rats (age 4-5 weeks and weight 95-110 g) were randomly divided into a shunt group and a control group with 10 rats of each group. The rats of the shunt group were treated with right common carotid artery-external jugular vein shunt to establish the rat models of left-to-right shunt PH

while the rats of the control group were given sham operation. The miRNA differential expressions in the pulmonary tissues that were collected from the two groups at 12 weeks after operation were examined by miRNA microarray. The target regulating genes were predicted by software such as miRanda

TargetScan and PicTar. Quantitative real-time PCR was applied to confirm the expressions of miR-98

miR-130b and miR-127.       Results      Mean pulmonary arterial pressure (mPAP)

percentage of pulmonary artery media thickness (MT%) and right ventricular hypertrophy index (RVHI) were significantly higher in the shunt group than in the control group (P0.01). The miRNA microarray results showed that 37 microRNAs were differentially expressed in the shunt group including 30 upregulated miRNAs (miR-122

miR-130b and miR-146b

etc.) and 7 downregulated miRNAs (miR-382

miR-192 and miR-29c

etc.) as compared with those in the control group. The RT-PCR results were in agreement with the microarray results.       Conclusion      There are differential expressions of miRNAs in pulmonary tissues of rats with left-to-right shunt pulmonary hypertension. These differentially expressed miRNAs may be involved in the pulmonary vessel reconstruction of PAH.