Korean Circ J.  2010 Sep;40(9):459-464. 10.4070/kcj.2010.40.9.459.

Gene Expression of Endothelin-1 and Endothelin Receptor A on Monocrotaline-Induced Pulmonary Hypertension in Rats After Bosentan Treatment

• Lim KA
• Kim KC
• Cho MS
• Lee BE
• Kim HS
• Hong YM

• KMID: 1456139
• DOI: http://doi.org/10.4070/kcj.2010.40.9.459

Abstract

BACKGROUND AND OBJECTIVES
Endothelin (ET)-1, a potent endothelium-derived vasoconstrictor peptide, has a potential pathophysiologic role in pulmonary hypertension. Bosentan, a dual ET receptor (ET(A)/ET(B)) antagonist, is efficacious in treatment of pulmonary hypertension. The objectives of this study were to investigate the expression of ET-1 and ET receptor A (ERA) genes and to evaluate the effect of bosentan in monocrotaline (MCT)-induced pulmonary hypertension.
MATERIALS AND METHODS
Four-week-old male Sprague-Dawley rats were treated as follows: control (n=36), subcutaneous (sc) injection of saline; MCT (n=36), sc injection of MCT (60 mg/kg); and bosentan (n=36), sc injection of MCT (60 mg/kg) plus 25 mg/kg/day bosentan orally.
RESULTS
Serum ET-1 concentrations in the MCT group were higher than the control group on day 28 and 42. Quantitative analysis of peripheral pulmonary arteries revealed that the increase in medial wall thickness after MCT injection was significantly attenuated in the bosentan group on day 28 and 42. In addition, the increase in the number of intra-acinar muscular arteries after MCT injection was reduced by bosentan on day 14, 28 and 42. The levels of ET-1 and ERA gene expression were significantly increased in the MCT group compared with control group on day 5, and bosentan decreased the expression of ET-1 on day 5.
CONCLUSION
ET-1 contributes to the progression of cardiopulmonary pathology in rats with MCT-induced pulmonary hypertension. Administration of bosentan reduced ET-1 gene expression in MCT-induced pulmonary hypertension in rats.

Keyword

Pulmonary hypertension; Endothelin; Gene expression; Monocrotaline; Bosentan

MeSH Terms

Animals
Arteries
Endothelin-1
Endothelins
Gene Expression
Humans
Hypertension, Pulmonary
Male
Monocrotaline
Pulmonary Artery
Rats
Rats, Sprague-Dawley
Receptors, Endothelin
Sulfonamides
Endothelin-1
Endothelins
Monocrotaline
Receptors, Endothelin
Sulfonamides

Figure

• 

  Fig. 1 Hematoxylin-eosin staining of lung tissue. Monocrotaline (MCT) treatment thickened the muscular layer of the pulmonary arteriole at 42 days (B) compared to controls (A), and bosentan blocked this effect (C). Magnification: ×400.

• 

  Fig. 2 Peripheral pulmonary artery thickness. MCT increased % wall thickness, and bosentan blocked this effect on days 28 (p<0.05) and 42 (p<0.05). MCT: monocrotaline.

• 

  Fig. 3 Bosentan reduced the MCT-induced increase in the number of muscularized peripheral pulmonary arteries on days 1, 14, 28, and 42 (p<0.05 in each group). MCT: monocrotaline.

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  Fig. 4 RT-PCR products for endothelin-1 and endothelin receptor A in rat lung tissue on day 5. The RT-PCR products from the transcripts of ET-1, endotelin receptor A and GAPDH were 156 bp, 118 bp and 89 bp. RT-PCR: reverse transcription-polymerase chain reaction, ET-1: Endothelin-1, GAPDH: glyceraldehyde 3-phosphate dehydrogenase.

• 

  Fig. 5 Gene expression of endothelin-1 after bosentan treatment. MCT increased ET-1 gene expression compared with controls on day 5 (p<0.05), and bosentan blocked this increase (p<0.05). *p<0.05 vs. control group, †p<0.05 vs. MCT group. MCT: monocrotaline, ET-1: Endothelin-1.

• 

  Fig. 6 Gene expression of endothelin-receptor A after bosentan treatment MCT increased ERA mRNA compared with controls on day 5 (p<0.05). *p<0.05 vs. control group. MCT: monocrotaline, ERA: endothelin receptor A.

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