Effects of rhubarb on migration of rat hepatic stellate cells.
OBJECTIVE
In chronic liver injury, hepatic stellate cells (HSCs) acquire an activated phenotype, migrate to the injured region in response to chemotactic factors, and produce extracellular matrix proteins including collagen. In this study, we investigated the effects of rhubarb (Rheum palmatum L.) on transforming growth factor (TGF)-beta1-induced expressions of alpha-smooth-muscle actin (SMA) and collagen, and the migration of HSCs.


METHODS
HSC-T6, a cell line of rat HSCs, was used in the in vitro experiments. An enzyme-linked immunosorbent assay and Sircol red assay were used to detect the expressions of alpha-SMA and collagen, respectively. HSC-T6 migration was assayed with a transwell apparatus. Phosphorylations of Smad2/3 and mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinase (ERK) 1/2, p38, and c-jun N-terminal kinase (JNK), were analyzed with Western blotting. Matrix metalloproteinase (MMP)-2 activity was examined by gelatin zymography.


RESULTS
The results revealed that a rhubarb extract concentration-dependently attenuated TGF-beta1-induced alpha-SMA and collagen expressions and migration of HSCs. The inhibitory effect of rhubarb was associated with (i) down-regulation of the phosphorylation of Smad2/3 and JNK, and (ii) attenuation of MMP-2 activity. Within the working concentrations used, the rhubarb extract did not affect cell viability of HSCs.


CONCLUSIONS
The results suggest that rhubarb attenuated TGF-beta1-mediated migration of HSCs possibly by interfering with Smad2/3 phosphorylation, the MAPK pathway, and MMP-2 activity.
Lin
Yun-Lian
YL
National Research Institute of Chinese Medicine, Taipei, Taiwan.
Wu
Ching-Fen
CF
Huang
Yi-Tsau
YT
D000199:Actins / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D002633:Chemotaxis / Q000187:drug effects*; D003094:Collagen / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D055166:Hepatic Stellate Cells / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D010766:Phosphorylation; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D012250:Rheum; D051899:Smad2 Protein / Q000378:metabolism; D051900:Smad3 Protein / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000378:metabolism
D000199:Actins; D003094:Collagen; D048031:JNK Mitogen-Activated Protein Kinases; D020778:Matrix Metalloproteinase 2; D010936:Plant Extracts; D051899:Smad2 Protein; D051900:Smad3 Protein; D053773:Transforming Growth Factor beta1; C497784:Smad2 protein, rat; C497787:Smad3 protein, rat; C498862:Acta2 protein, rat; C522363:Mmp2 protein, rat