Objective: To investigate the expression of GATA6 gene in lung tissue of rat with pulmonary hypertension.
Methods: Male Sprague-Dawley rats (350 to 400 g) were received monocrotaline (MCT) (60 mg/ kg) subcutaneous injection on day 7 after left lung resection. Mean pulmonary artery pressure (mPAP), right ventricle (RV) / [left ventricle (LV)+ interventricular septum (S)] ratio and pulmonary artery wall thickness (WT%) were detected on day 1, 21, 35 after left lung resection, respectively. Neointimal formation in small pulmonary vessels was observed by Von Gienson stain. The level of expression of GATA6 mRNA in lung tissue was detected by reverse transcription polymerase chain reaction (RT-PCR).
Results: Neointimal changes developed in right lung intra-acinar vessels on day 35 after left lung resection (day 28 after MCT injection). Neointimal lesions did not develop in control animals. Animals treated with left lung resection plus MCT had significantly increased mPAP values on day 21 [(27.10 +/- 2.02) mmHg, 1 mmHg = 133.32 Pa], with a further increase on day 35 (39.75 +/- 3.62) mmHg, as compared with control animals [(16.80 +/- 1.03) mmHg, day 21; (17.10 +/- 1.20) mmHg, day 35, P < 0.0001]. The RV/(LV+S) ratio increased from 0.266 +/- 0.015 (day 1) to 0.456 +/- 0.025 (day 21) and 0.627 +/- 0.040 (day 35), as compared with those of control animals (P < 0.0001) (0.267 +/- 0.016 (day 1), 0.272 +/- 0.015 (day 21) and 0.257 +/- 0.019 (day 35)]; Compared with normal pulmonary arteries, MCT injection after left lung resection resulted in severe media hypertrophy after 35 days. The level of GATA6 mRNA in rats received left lung resection plus MCT was downregulated about 4-fold on day 35, compared with that in control animals, and these tendency was observed on day 21 after left lung resection.
Conclusion: The expression of GATA6 gene is downregulated in neointimal model of pulmonary hypertension, it suggests that GATA6 may play a key role in pulmonary vascular remodeling.