Abstract: Objective To observe the effect of leptin on the expression of MMP-2 and KIF1B in first trimester trophoblastic cells, and explore the role of KIF1B in the regulation of leptin on MMP-2 secretion. Methods First trimester trophoblasts were isolated by conventional methods from the villi (6 to 9 weeks) of normal pregnant women by artificial abortion, and then divided into 6 groups: control, leptin (100 and 500 μg/L), KIF1B-siRNA, leptin (100 and 500 μg/L) + KIF1B-siRNA. After 24 h, we employed zymography for detecting the level of MMP-2 in supernatant, RT-PCR for the change of MMP-2, OB-Rl and KIF1B mRNA expression, and Western blot for the change of KIF1B protein expression. Results MMP-2 expression in trophoblasts was significantly enhanced by leptin (100 and 500 μg/L) compared with the control group (100 μg/L: from 0.11±0.02 to 0.18±0.05 at mRNA level, P<0.05). The up-regulation of OB-Rl and KIF1B depended on leptin (P<0.05). KIF1B-siRNA partially inhibited the up-regulation of MMP-2 secretion by leptin. Conclusion Leptin up-regulates MMP-2 secretion by the pathway of leptin R-KIF1B, consequently enhances the invasion of first trimester trophoblasts, which offers new basal data for elucidating the mechanism of invasion regulation of trophocytes.

Key words: Leptin, trophoblast, Matrix metalloproteinase-2, Kinesin 1B, Invasion