Fig. 1.

Pancreatic stellate cell (PSC) activation is characterized by the loss of autofluorescent vitamin A droplets and expression of α-smooth muscle actin (α-SMA) and platelet-derived growth factor-β (PDGFR-β). A: vitamin A fat droplets were evident as blue autofluorescence under UV light in the cytoplasm of PSCs after 24 h in culture. This is a characteristic of quiescent stellate cells. B: cytoplasm of PSCs in culture stained positively for the β subunit of the PDGF receptor (PDGF-β). C: after EtOH (150 mM) stimulation for 24 h, PSCs underwent activation with morphological and functional changes typical of myofibroblast-like cells. The cell body of PSCs expanded 2.5-fold, and PDGF-β receptor was positively stained. D: after tumor necrosis factor-α (TNF-α, 1 ng/ml) exposure for 24 h, the cell bodies of PSCs were enlarged. E and F: histograms show measurements of the soma area of PSCs (E) and the relative staining density (F) of PDGF-β receptor when treated with 50 mM (n = 60) or 150 mM EtOH (n = 50) or 1 ng/ml TNF-α (n = 60) for 24 h. The cell body size of PSCs significantly increased with exposure to the high dose of EtOH and to TNF-α. The intensity of the PDGF-β receptor-like immunoreactivity remained constant as the cell body area expanded, suggesting an overall increase in PDGF-β receptor in the PSCs soma as reported by others previously [EtOH vs. control (n = 70); TNF-α vs. control, ***P < 0.001, Student's t-test].