[Effects of tetramethylpyrazine on angiotensin II -induced proliferation and type I collagen synthesis of rat cardiac fibroblasts].
OBJECTIVE
To observe the effects of tetramethylpyrazine (TMP) on the proliferation and type I collagen synthesis of rat cardiac fibroblasts (CFBs) induced by angiotensin II (Ang II), and to explore the mechanism of TMP in treating myocardial fibrosis.


METHODS
CFBs were isolated from neonatal rats, and the fourth-passage CFBs were used in the entire test and were stimulated by 0.1 micromol/L Ang II in vivo. The CFB proliferation was measured by methyl thiazolyl tetrazolium (MTT) assay. Type I collagen in the cell culture supernatant was measured by enzyme-linked immunosorbent assay. The expression of mRNA of type I collagen was semi-quantitatively measured by reverse transcription-polymerase chain reaction (RT-PCR).


RESULTS
(1) In MTT assay, the optical density of CFBs cultured with 0.1 micromol/L Ang II was higher than that of the blank control cultured with 2% fetal bovine serum-Dulbecco's modified Eagle's medium (FBS-DMEM). The difference was statistically significant (P < 0.05). Both optical densities of CFBs cultured with 0.1 micromol/L Ang II plus 800 microg/mL TMP and 0.1 micromol/L Ang II plus 600 microg/mL TMP were lower than that of CFBs cultured with 0.1 micromol/L Ang II, but only the difference between 0.1 micromol/L AngII plus 800 microg/mL TMP group and 0.1 micromol/L Ang II group was significant (P < 0.05). (2) The content of type I collagen secreted by CFBs cultured with 0.1 micromol/L Ang II was higher than that with 2% FBS-DMEM (P < 0.01). The content of type I collagen secreted by CFBs cultured with 0.1 micromol/L Ang II plus 800 microg/mL TMP was lower than that with 0.1 micromol/L Ang II (P < 0.05). (3) The level of type I collagen mRNA in 0.1 micromol/L Ang II group was higher than that in blank control group, and lower than that in 0.1 micromol/L Ang II plus 800 microg/mL TMP group. Both the differences between 0.1 micromol/L Ang II group and the blank control group and between 0.1 micromol/L Ang II group and 0.1 micromol/L Ang II plus 800 microg/mL TMP group were statistically significant (P < 0.05).


CONCLUSIONS
TMP can not only inhibit the proliferation of CFBs, but also decrease the secretion and the mRNA expression level of collagen I in cultured CFBs of rat which are increased by Ang II.
Zhang
Dong-mei
DM
Key Laboratory of Chinese Internal Medicine of the Ministry of Education, Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing 100700, China. chaweto@126.com
Qin
Ying
Y
Lu
Xi-ying
XY
Wu
Ai-ming
AM
Zhu
Ling-qun
LQ
Wang
Shuo-ren
SR
Jiang
Liang-duo
LD
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D049109:Cell Proliferation / Q000187:drug effects*; D024042:Collagen Type I / Q000096:biosynthesis*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D009206:Myocardium / Q000166:cytology / Q000378:metabolism; D011719:Pyrazines / Q000494:pharmacology*; D017207:Rats, Sprague-Dawley
D024042:Collagen Type I; D011719:Pyrazines; D000804:Angiotensin II; C017953:tetramethylpyrazine