Effects of Bosentan Treatment on Angiotensin Converting Enzyme in Monocrotaline Induced Pulmonary Hypertension Rats

Sung Jin Kim; Ji Hae Cha; Hae Ryun Lee; Young Mi Hong

doi:10.5646/jksh.2011.17.1.28

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Kim, Cha, Lee, and Hong: Effects of Bosentan Treatment on Angiotensin Converting Enzyme in Monocrotaline Induced Pulmonary Hypertension Rats

Original Article

J Korean Soc Hypertens 2011;17(1):28-36.

Published online: 10 March 2011

DOI: https://doi.org/10.5646/jksh.2011.17.1.28

Effects of Bosentan Treatment on Angiotensin Converting Enzyme in Monocrotaline Induced Pulmonary Hypertension Rats

Sung Jin Kim, MD, Ji Hae Cha, MD, Hae Ryun Lee, MD, Young Mi Hong, MD

Deparment of Pediatrics, Ewha Womans University School of Medicine, Seoul, Korea

Tel: 02) 2650-2841, Fax: 02)2653-3718 E-mail: hongym@chollian.net, ymhong@ewha.ac.kr

Received 21 January 201117 March 2011 Accepted 18 March 2011

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

ABSTRACT

Background:

Pulmonary artery hypertension is characterized by persistent increase of vascular resistance, and is associated with right ventricle failure. We investigated changes of plasma renin, serum aldosterone, angiotensin converting enzyme (ACE) concentrations, ACE gene expressions and protein contents after bosentan treatment.

Methods:

Six-week-old male Sprague-Dawley rats were divided into three groups: control (C) group, monocrotaline (M) group, and bosentan (B) group. Groups M and B were subcutaneously administered with 60 mg/kg of monocrotaline. In group B, 20 mg/kg/day of bosentan was administered by gavage twice a day. The rats were sacrificed after 1, 5, 7, 14, and 28 days. Changes of ACE gene expressions were analyzed by reverse transcription-polymerase chain reaction. Also, plasma renin, serum aldosterone, and ACE levels were measured.

Results:

Serum aldosterone levels were significantly increased in group M compared with group C and significantly decreased after bosentan treatment on day 28. Serum ACE concentrations were significantly decreased compared with group M after bosentan treatment on day 28. Gene expressions of ACE were significantly increased in group M compared with group C on day 5 and significantly decreased after bosentan treatment on day 7 and 14. ACE protein contents significantly increased in group M compared with group C in week 2 and 4. It significantly decreased after bosentan treatment in week 2.

Conclusions:

The renin-angiotensin system is associated with pulmonary artery hypertension. To investigate the effects of bosentan on the renin-angiotensin system in pulmonary artery hypertension, further studies on the effects of bosentan according to different doses are required in the future.

Keywords: Pulmonary artery hypertension, Monocrotaline, Bosentan, Angiotensin converting enzyme, Gene expression

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Fig. 1.

Typical example of RT-PCR products of ACE mRNA in lung tissue. The RT-PCR products from the transcripts of ACE and GAPDH were 135 bp and 89 bp. RT-PCR, reverse transcription polymerase chain reaction; ACE, angiotensin converting enzyme; GADPH, glyceraldehyde 3-phosphate dehydrogenase.

Fig. 2.

Changes in serum aldosterone levels on day 28. Serum aldosterone levels significantly increased in group M compared with group C and decreased after bosentan treatment on day 28. C, control; M, monocrotaline; B, bosentan. *p < 0.05 significantly different from C group. ^†p < 0.05 significantly different from M group.

Fig. 3.

Changes in serum ACE levels on day 28. Serum ACE levels significantly decreased compared with M group after bosentan treatment on day 28. ACE, angiotensin converting enzyme; C, control; M, monocrotaline; B, bosentan. ^†p<0.05 significantly different from M group.

Fig. 4.

Gene expressions of ACE after bosentan treatment. Group M presented with significantly increased gene expression of ACE on day 5. It significantly decreased on day 7 and 14 after bosentan treatment. ACE, angiotensin converting enzyme; C, control; M, monocrotaline; B, bosentan. *p < 0.05 significantly different from C group. ^†p < 0.05 significantly different from M group.

Fig. 5.

ACE protein contents by western blot analysis. ACE protein contents significantly increased in the M group compared with group C. It significantly decreased after bosentan treatment in week 2 (A). ACE protein contents significantly increased in the M group compared with group C in week 4. However, it did not change after bosentan treatment in week 4 (B). ACE, angiotensin converting enzyme; GADPH, glyceraldehyde 3-phosphate dehydrogenase; C, control; M, monocrotaline; B, bosentan. #p < 0.05 significantly different from C group. *p < 0.05 significantly different from M group.

Table 1.

Gene expression levels of angiotensin converting enzyme in the lungs by RT-PCR

Day	No	Group C	Group M	Group B
1	6	1±0.39	1.21±0.40	0.94±0.42
5	6	1±0.07	1.76±0.39^*	1.48±0.31
7	6	1±0.27	0.82±0.21	0.24±0.08^†
14	6	1±0.27	0.82±0.22	0.24±0.08^†
28	6	1±0.36	1.44±0.21	1.60±0.35

RT-PCR, reverse transcription polymerase chain reaction; C, control; M, monocrotaline; B, bosentan.

^* p<0.05 significantly different from C group.

^† p<0.05 significantly different from M group.

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