Abstract
Purpose::
To examine the effect of tetrandrine on fibrogenic behaviors of cultured human subconjunctival fibroblasts (hSCFs). Tetrandrine is a bioactive constituent of an herbal medicine.
Methods::
Confluent cultures of hSCFs were treated with tetrandrine (0 - 5.0 micro g/ml). Its effects on expression of a-smooth muscle actin, collagen I and III, and fibronectin were investigated by using immunocytochemistry, western blotting, enzyme-immunoassay or real-time RT-PCR. Tetrandrin's effect on cell migration or proliferation was determined by in vitro wound closure model in a cell monolayer or by Alamar blue assay, respectively. Effect of tetrandrine on Smad2 phosphorylation and Smad7 expression was examined by immunocytochemistry and western blotting.
Results::
Adding tetrandrine suppressed expression of collagens and fibronectin at mRNA or protein level and cell migration, but not cell proliferation. Treatment of cells with tetrandrine up-regulated expression of Smad7, an inhibitory Smad, and reduced nuclear translocation of phospho-Smad2 in cells. Control cells showed a peak of Smad2 acticvation at 0.5 hr.
Conclusions::
Tetrandrine inhibits fibrogenic behaviors of cultured hSCFs. The mechanism of action might include that this compound induce Smad7 that resulted in supprssion of Smad2 signal.
Keywords: conjunctiva • extracellular matrix • growth factors/growth factor receptors