Characteristics of pulmonary vascular remodeling in rat model of pulmonary hypertension in left heart disease

Abstract

Objective: To investigate pulmonary vascular remodeling in rat model of pulmonary hypertension in left heart disease (PH-LHD). Methods: A total of 66 male minor Sprague-Dawley (SD) rats were randomly divided into control group (n=6), sham operation group (n=6) and model group (n=54). The rats in the control group entered the experimental procedure immediately without any treatment, and the rats in the sham operation group entered the experimental procedure 64 days after sham operation, and the rats in model group entered the experimental procedure (6 rats each) on day 1, day 3, day 5, day 8, day 15, day 22, day 36, day 50 and day 64 respectively after supracoronary aortic banding successfully. The lung tissue was fixed and cut and made into pathological sections to observe the characteristics of pulmonary vascular remodeling. Results: Medial thickening was mainly observed in pulmonary arterioles with diameter <100 μm [(11.17±1.03)%]. Additionally, medial thickening was seen in pulmonary arterioles with diameter 50-100 μm and 20-50 μm from day 15 [(12.73±1.15)%] and day 50 [(14.53±1.53)%], respectively. Medial muscularize of pulmonary arterioles were mainly observed in arterioles with diameter 20-50 μm, and deteriorated with time. Reduced pulmonary arteriole lumen size were observed with diameter 20-50 μm since day 50 (P<0.05). Conclusion: Pulmonary arteries with diameter >100 μm have little effect on the reconstruction of pulmonary vessels in PH-LHD rat model. However, arterioles with diameter 20-50 μm and 50-100 μm are the most important vessels involved in the formation of pulmonary hypertension, especially 20-50 μm.