OBJECTIVETo test the changing expression level of Annexin I, cPLA(2) and PCNA in the palatine process of cleft-palate mice A/J and C57B/6j induced by dexamethasone. To discuss the developing mechanism of cleft-palate and the corresponding preventive methods.

METHODs Pregnant mice A/J and C57BL/6j were randomly divided into normal group as blank control, group with deformity induced by dexamethasone, group given VitB(12) as antagonist to deforming factor, group given only VitB(12). The relative quantity of Annexin I, Cpla2 and PCNA were detected by immunoblotting.

RESULTSAmong mice A/J, with the development of palatine process, Annexin I's expression level was increased in the normal group, and other groups showed the similar changes. Annexin I's expression level was significantly higher in group DEX and group DEX + VitB(12) than in normal group and VitB(12) group of, while there was no significant difference between normal group and VitB(12) group. But the changes of cPLA(2) and PCNA expression level was in an opposite direction, with development it decreased in the normal mice's palatine process. In mice C57B/6j there was no significant difference between normal group and group DEX on the measured quantity of Annexin I, cPLA(2) and

CONCLUSIONSAnnexin I and cPLA(2) introduce glucocorticoid to induce cleft-palate. VitB(12) can not inhibit DEX's enhancing effect on the expression level of Annexin I, but it can antagonize DEX's inhibiting effect on expression level of cPLA(2), which is probably one of the mechanisms why VitB(12) antagonize glucocorticoid's deforming effect.