GROWTH-FACTOR MODULATION OF RAT PLEURAL MESOTHELIAL CELL MITOGENESIS AND COLLAGEN-SYNTHESIS - EFFECTS OF EPIDERMAL GROWTH-FACTOR AND PLATELET-DERIVED GROWTH-FACTOR

This study examined the effects of an epithelial and a mesenchymal gro wth factor on pleural mesothelial cell proliferation and collagen synt hesis, functions that may be important in the response of the pleura t o injury. Epidermal growth factor (EGF) and platelet-derived growth fa ctor (PDGF) added singly caused significant increases relative to cont rol in both the uptake of [H-3]thymidine into the cellular DNA of subc onfluent monolayers and of7 [H-3]proline into collagenase-sensitive pr otein. Combinations of EGF and PDGF resulted in more than additive inc reases in proliferation and additive increases in collagen production relative to each factor alone. Media from control and growth factor-st imulated PMC demonstrated no gelatinase or collagenase activity, sugge sting that the increase in net collagen production was secondary to en hanced synthesis. These data demonstrate that both epithelial and mese nchymal growth factors can stimulate PMC proliferation and collagen sy nthesis and that these growth factors have even greater effects when c ombined, particularly in regard to cellular proliferation. Increases i n PMC proliferation and collagen synthesis in response to these growth factors may be important in healing the pleura after injury by a vari ety of disease processes.