[Upregulated Rho-kinase and increased phosphorylation of myosin-binding subunit of myosin phosphates are key players in a porcine coronary artery spasm model with interleukin-1beta].
OBJECTIVE
Phosphorylation of myosin light chain (MLC) is one of the most important steps for vascular smooth muscle contraction and Rho-kinase is involved in this process. We investigated the role of Rho-kinase in a porcine coronary artery spasm model with interleukin-1beta.


METHODS
Segments of left coronary artery adventitia were surrounded by normal saline (n = 8) or IL-1beta agarose microne (n = 8) for 2 weeks. Vasospastic responses to intracoronary serotonin or histamine then studied at the saline or IL-1beta-treated site. The Rho-kinase mRNA expression in the treated site was measured by reverse transcription-polymerase chain reaction analysis (RT-PCR). The extent of phosphorylation of myosin-binding subunit of myosin phosphates (MBS, one of the major substrates of Rho-kinase) were quantified by Western blot analysis.


RESULTS
Intracoronary serotonin or histamine repeatedly induced coronary artery spasm and coronary arterial stenosis was evidenced at IL-1beta-treated site. Expression of Rho-kinase mRNA in IL-1beta-treated site was significantly increased compared to saline treated site (98.20% +/- 7.66% vs. 63.70% +/- 4.26%, P < 0.05). Western blot analysis showed that during the serotonin-induced contractions the extent of phosphorylation of MBS was also significantly increased in the spastic site (25,485 +/- 4745 vs. 6510 +/- 779, P < 0.05).


CONCLUSIONS
Rho-kinase upregulation at the spastic site and increased phosphorylation of myosin-binding subunit of myosin phosphates are key players in inducing vascular smooth muscle hypercontraction in this porcine model.
Guan
Qi-gang
QG
Department of Cardiology, First Affiliated Hospital of China Medical University, Shenyang 110001, China.
Zeng
Ding-yin
DY
Sun
Xi-zhuo
XZ
Miao
Zhi-Lin
ZL
Zhou
Xu-chen
XC
He
Xue-zhi
XZ
Han
Feng-tong
FT
Cheng
Ying
Y
Zhang
Li
L
D000818:Animals; D003329:Coronary Vasospasm / Q000378:metabolism* / Q000473:pathology; D004195:Disease Models, Animal; D053583:Interleukin-1beta / Q000009:adverse effects* / Q000378:metabolism; D008297:Male; D018994:Myosin Light Chains / Q000378:metabolism*; D010766:Phosphorylation; D012333:RNA, Messenger / Q000378:metabolism; D013552:Swine; D054460:rho-Associated Kinases / Q000378:metabolism*
D053583:Interleukin-1beta; D018994:Myosin Light Chains; D012333:RNA, Messenger; D054460:rho-Associated Kinases