[Effect of angiotensin II on Rho-Rock pathway in rat hepatic stellate cell contraction].
OBJECTIVE
To investigate the mechanisms of angiotonin II (AngII)-induced Ca(2+)-independent pathways mediated by Rho kinase in hepatic stellate cells (HSCs).


METHODS
HSC-T6 cells were treated with 1 micromol/L of AngII, and the subsequent cell contraction was directly observed with silicone rubber membrane culture method. The cells with 10 micromol/L AngII treatment were examined for myosin light chain (MLC) phosphorylation level using Western blotting, and the effects of irbesartan (a specific inhibitor of AngII 1- receptor) and Y27632 (a Rho kinase inhibitor) on AngII-induced MLC phosphorylation were evaluated. RT-PCR was used to detect the expression of Rock2 in Ca(2+)- independent pathways mediated by Rho kinase.


RESULTS
AngII induced HSC contraction and time-dependent MLC phosphorylation changes, which peaked 15 min after the treatment followed by gradual reduction. Irbesartan or Y27632 treatment significantly lowered MLC phosphorylation level in AngII-induced cells (P<0.01). The mRNA expression of Rock2 increased significantly after AngII treatment (P<0.01), but decreased following subsequent irbesartan or Y27632 treatment.


CONCLUSIONS
AngII induces HSC contraction through Ca(2+)-independent pathways mediated by Rho kinase.
Zhang
Xiao-Lan
XL
Department of Digestive Diseases, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China. zhangxiaolanny@163.com
Li
Xu
X
Xiao
Bing
B
Huang
Mao-Liang
ML
Meng
Ying
Y
Li
Ying-Fei
YF
Wang
Yuan-Yuan
YY
Song
Wei-Bing
WB
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D002465:Cell Movement / Q000502:physiology; D048430:Cell Shape / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D055166:Hepatic Stellate Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D010766:Phosphorylation / Q000187:drug effects; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D054460:rho-Associated Kinases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*
D012333:RNA, Messenger; D000804:Angiotensin II; C515852:ROCK2 protein, human; D054460:rho-Associated Kinases