L-ARGININE REGULATES APOPTOSIS OF PULMONARY ARTERY SMOOTH MUSCLE CELLS IN RATS WITH HYPOXIC PULMONARY VASCULAR STRUCTURAL REMODELING

Qi JG¹, Du JB¹, Guo ZL¹, Zhao B², Zhang QY¹

¹ First Hospital of Peking University, Beijing, China

² Beijing Ji Shui Tan Hospital, Beijing, China

Objective: To explore the impact of L-arginine on apoptosis of smooth muscle cells in pulmonary arteries of the rats with hypoxic pulmonary vascular structural remodeling.

Methods: Seventeen Wistar rats were randomly divided into hypoxia group ( n=5 ), hypoxia with L-arginine group ( n=5 ) and control group ( n=7 ). Hypoxic challenge was performed by putting the rats into a normobaric hypoxic chamber with an oxygen concentration of 10%��0.5% for two weeks. Pulmonary vascular microstructure was measured. Apoptotic smooth muscle cells in pulmonary arteries were detected by TdT-mediated dUTP-biotin nick end labeling, and the expression of Fas protein was detected using immunohistochemistry technique.

Results: pulmonary vascular structural remodeling developed after 2-week hypoxia. Meanwhile, the percentage of apoptotic smooth muscle cells to smooth muscle cells in pulmonary arteries was markedly decreased in hypoxic rats compared with normal controls. The expression of Fas protein of hypoxic rats was inhibited obviously. L-arginine ameliorated pulmonary vascular structural remodeling of hypoxic rats in association with an increase in the percentage of apoptotic smooth muscle cells to smooth muscle cells and a strengthened Fas expression by pulmonary artery smooth muscle cells.

Conclusion: L-arginine plays an important role in the regulation of development of hypoxic pulmonary vascular structural remodeling through promoting Fas expression and thereby strengthening apoptosis in pulmonary artery smooth muscle cells.

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