Combined effect of retinoic acid and vascular endothelial growth factor on compensatory lung growth following unilateral pneumonectomy in rats

Saravanan R., Rajaram S.


Background: The most common complication of complete or partial pneumonectomy is insufficient oxygenation due to loss of respiratory unit leading to reduced quality of life. Retinoic acid and vascular endothelial growth factors are two important signaling molecules essential during normal lung development and together they could enhance the compensatory lung growth and function following pneumonectomy.

Methods: Unilateral pneumonectomy of left lung was performed in male wistar albino rats. Retinoic acid (RA) (0.5 mg/kg), vascular endothelial growth factor (VEGF) 5µg/day and vehicle were administered intraperitoneally for 10 days. Lung weight, lung volume, arterial blood gases (ABG), protein and DNA estimations were performed on the contralateral lung.

Results: Rats treated with RA alone and combination of RA and VEGF increased the weight and volume of the compensatory lung as compared to control. Protein and DNA concentrations were also increased in the contralateral lung in rats treated with RA alone and RA with VEGF as compared to control. In arterial blood gas analysis, rats treated with combination of RA and VEGF shows an increase in partial pressure of oxygen and oxygen saturation as compared to control, whereas rats treated with RA alone did not significantly improve the oxygen saturation.

Conclusions: Combination of VEGF with RA had accelerated compensatory lung growth in pneumonectomized rats probably by increasing type II pneumocyte proliferation and new blood vessels formation in the lung. There is significant increase in arterial blood gases compared to retinoic acid group possibly by the formation of new blood vessels by VEGF which is essential for improving oxygenation of blood and to improve quality of life.


RA, VEGF, Pneumonectomy, Compensatory growth, ABG

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