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ALTERATION OF MICRO- AND ULTRA PATHOLOGIC STRUCTURE AND GASOUS MOLECULE IN HIGH PULMONARY BLOOD FLOW-INDUCED PULMONARY HYPERTENSION

Qi JG, Du JB, Li J, Wei B, Tang XY, Tang CS

First Hospital, Peking University, Beijing, China

Objective: To examine the alteration of micro- and ultra pathologic structure and gaseous molecule in rats with high pulmonary blood flow-induced pulmonary hypertension.

Methods: Pulmonary hypertension of rats was induced by abdominal aorta and inferior vena cava shunting procedure. Pulmonary hemodynamics was monitored by right cardiac catheterization and micro- and ultra pulmonary arterial structure was examined with light and electric microscope after 11-week operation. Meanwhile, plasma nitric oxide and carbon monoxide was measured by spectrophotometry. Endothelial nitric oxide synthase expression was detected by immunohistochemistry.

Results: After 11-week abdominal aorta and inferior vena cava shunting procedure, pulmonary artery mean pressure and the ratio of right ventricular mass to left ventricular plus ventricular septal masses (RV/LV+S) were significantly increased (P<0.01). Muscularization of small pulmonary artery and relative medial thickness and relative medial area were obviously increased in shunt rats compared with controls. Electric microscopic findings revealed that increased proliferation of SMC and EC of pulmonary arteries in rats with arterial-venous shunting. Plasma nitric oxide was increased and nitric oxide synthase expression by pulmonary artery EC significantly augmented in pulmonary hypertensive rats as compared with controls. Plasma carbon monoxide level, however, was not altered in rats with shunting as compared with controls (P>0.05).

Conclusion: Pulmonary artery vascular structure remodeling is the important pathologic basis of pulmonary hypertension induced by a left-to-right shunt, and nitric oxide other than carbon monoxide might play an important role in the development of high pulmonary blood flow-induced pulmonary hypertension.