[Mechanism of insulin-like growth factor-I affecting adhesion of trophoblast cells in vitro].

To investigate the mechanism of insulin-like growth factor-I (IGF-I) affecting adhesion of trophoblast cells in vitro. Trophoblast cells were obtained from early gestation at artificial abortion to set up the in vitro trophoblast cell adhesion model. The trophoblast cells were incubated with or without 10 nmol/L IGF-I and were divided into three groups (10 nmol/L IGF-I, 10 nmol/L IGF-I + alpha v beta3Ab, and control). The amount of adhered cells was assessed by examining absorbency using enzyme-linked immunoassay. Morphological changes were studied using scanning electron microscopy. The expression of phosphorylated focal adhesion kinase was determined by immunocytochemistry. After serum-starved trophoblast cells were incubated only with IGF-I, the mean absorbency was 0.491 +/- 0.049, obviously higher than control 0.198 +/- 0.022 and the difference was dramatic (P < 0.01). When cells were pre-treated with antibody against alpha v beta3 integrin and then incubated with IGF-I, the mean absorbency was only 0.184 +/- 0.031, distinctly lower than that incubated with IGF-I, and the difference was significant (P < 0.01), however, compared with control, there was no significant difference (P > 0.05). Scanning electron microscopy highlighted a dramatic increase in lamellipodial formation and extension in the IGF-I treated cells compared with control. Immunocytochemistry staining showed phosphorylated focal adhesion kinase was expressed in the trophoblast cells treated with IGF-I. 10 nmol/L IGF-I can significantly stimulate trophoblast cells adhesion to fibronectin, but antibody against alpha v beta3 integrin obviously blocks its adhesion. IGF-I can stimulate lamellipodial formation and extension at the adhesion sites, and promote adhesion of trophoblast cells to fibronectin by activating phosphorylated focal adhesion kinase.