Purpose:
To evaluate the anti-fibrotic effects of ethanol extract of
Rhus javanica
Linn. (Anacardiaceae)
(RJE) in activated hepatic stellate cells (HSCs) as well as explore the underlying mechanisms.
Methods:
The cytotoxic effect of RJE (100, 300 and 500 μg/mL) was analyzed using 3-[4, 5-
dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide (MTT) assay in Chang liver cells. The mRNA
expression of collagen type I, alpha 2 (COL1A2), transforming growth factor-beta (TGF-β), α-smooth
muscle actin (α-SMA) and platelet-derived growth factor (PDGF) were determined using reverse
transcription-polymerase chain reaction (RT-PCR) in HSCs. Protein expression of collagen and Smad
were measured by Western blot analysis.
Results:
Treatment with RJE extract at 100, 300 and 500 μg/mL did not show any signs of cytotoxicity
to Chang liver cells. RJE at 500 μg/mL concentration influenced the morphology, reduced the stretched
fiber and decreased the number of viable cells in activated HSCs. The increased expressional levels of
fibrosis mediators such as COL1A2, TGF-β, α-SMA were decreased by RJE (500 μg/mL) pre-treatment.
Quantification data showed that the increased band intensity of COL1A2 (1.41 ± 0.08), TGF-β (1.23 ±
0.13), α-SMA (1.71 ± 0.14) were significantly (p < 0.05) reduced to 0.39 ± 0.12, 0.35 ± 0.11 and 0.04 ±
0.08, respectively upon RJE treatment. However, RJE did not suppress the expression of PDGF gene.
Mechanistic study revealed that RJE prevented fibrosis in HSCs via regulation of TGF-β and Smad
signaling pathways.
Conclusion:
The findings show that RJE inhibits fibrosis production in HSCs and can be developed as
a novel therapy for hepatic fibrosis. This is the first report showing the beneficial effects of
R. javanica
as an anti-fibrotic agent.
