Objective To investigate the difference of the expression of HOXAIO gene in placental villi before and after the onset of labor. Methods Immunohistochemistry was used to detect the location of HOXAIO in placental villi. The expression of HOXAIO mRNA and protein were measured by RT-PCR and Western blotting. Results lmmunohistochemistry showed that HOXAIO was only weakly expressed in placental villi of the natural labor group. However, it was strongly expressed in placental Villi of the surgical labor group. RT-PCR and Western blotting showed that the expression of HOXAIO mRNA and protein were significantly lower in the natural labor group than in the surgical labor group （P〈0.05）. Conclusion The lower expression of HOXAIO during the onset of labor may be one of the major factors in initiating the normal labor. And to some extent, the lower expression of HOXAIO gene in the natural labor group may be related to ＂functional progesterone withdrawal＂.
Hong HEDe-min PURong LIUQiong-hua CHENDong-rui DENGTian LI
