[The vasoactive material and pulmonary vascular structural remodeling in rats]

Area of Science:

• Physiology
• Cardiovascular Research
• Altitude Medicine

Background:

• Hypoxia triggers pulmonary vascular structural remodeling, a key factor in high-altitude pulmonary hypertension.
• Vascular endothelial growth factor (VEGF) and endothelin-1 (ET-1) are implicated in vascular remodeling, but their specific roles in hypoxia-induced pulmonary hypertension require further elucidation.

Purpose of the Study:

• To investigate the roles of VEGF and ET-1 in pulmonary vascular structural remodeling in rats and pika exposed to high altitude.
• To compare the expression levels of VEGF and ET-1 and assess pulmonary vascular changes between rats and pika under hypoxic conditions.

Main Methods:

• Wistar rats were exposed to simulated high altitude (3,417 m) for 24 hours, 2 weeks, and 3 weeks.
• Serum levels of VEGF and ET-1 were measured using ELISA. Pulmonary artery structural changes (MA, PMA, NMA) and right ventricular hypertrophy (RV/LV + S ratio) were assessed histologically and morphometrically.

Main Results:

• Hypoxic rats showed increased pulmonary artery muscularization (MA, PMA) and decreased non-muscularized arteries (NMA), alongside right ventricular hypertrophy.
• ET-1 levels were significantly different in pika compared to hypoxic rats at all time points.
• VEGF levels were higher in rats after 2 and 3 weeks of hypoxia compared to pika, but similar between pika and rats at 24 hours.

Conclusions:

• VEGF and ET-1 play significant roles in the muscularization of pulmonary vessels and the development of hypoxic pulmonary hypertension in rats.
• In pika, VEGF and ET-1 may primarily function to maintain normal organic function, suggesting species-specific adaptations to hypoxia.