Cellular fibronectin stimulates hepatocytes to produce factors that promote alcohol-induced liver injury

Figure 5 Effect of cellular fibronectin on the secretion of tissue inhibitor of metalloproteinase-2 by cultured hepatocytes isolated from control and ethanol-fed rats. The level of tissue inhibitor of metalloproteinase (TIMP)-2 released into the cell culture media of hepatocytes after 20 h of treatment with cellular fibronectin (cFn) was determined as described in the Material and Methods. At the higher concentrations of exogenous cFn (4 μg/mL and 7.5 μg/mL), hepatocytes from both control and ethanol-fed animals secreted significantly higher levels of TIMP-2 forms than corresponding untreated cells, and those incubated in the presence of low concentrations of cFn. The cells from ethanol-fed animals cultured in the presence of 7.5 μg/mL cFn were significantly more responsive than those of the controls (A). Plasma fibronectin treatment produced no effect on either cell type (B). Data are represented as means ± SEM. Ethanol values significantly different from those of the control are expressed as ^aP < 0.05, and treatment significantly different from untreated cultures is expressed as ^bP < 0.05. (n = 11 experiments).