Study on the Shh related signal factors in mouse embryonic palatal process interfered by dexamethasone and vitamin B12

Abstract:

Objective: To explore the regulation between the Shh related signal pathway cytokines, cell cycle regulator and primary cilia depolymerization factors as well as the changing relationship among them after the treatment of dexamethasone and its antagonist vitamin B₁₂intervention in the key period of pregnancy. Methods: C57BL/6J pregnant mice at specific period of pregnancy were intraperitoneally injected with a certain dose of saline (control group), dexamethasone (dexamethasone group), vitamin B₁₂ (vitamin B₁₂ group), vitamin B₁₂+dexamethasone (dexamethasone+vitamin B₁₂group), and they were observed for the fusion of embryo and palatal process in each group on 13.5 and 17.5 days of pregnancy. The expression changes of Smo, Ptch1, Cyclin D1 and Aurora A in the palatal process of mice on 13.5 days of pregnancy in each group were detected by Western blot, and analyzed statistically. Results: Dexamethasone retarded the development of the embryonic palatal process leading to cleft palate, while vitamin B₁₂intervention partially restored the development of the embryonic palatal process. Western blot results showed that, compared with the control group, the expressions of Ptch 1, Aurora A and Cyclin D1 were significantly decreased in dexamethasone group (all P=0.000), but the expression of Smo had no significant change (P=0.695). Compared with dexamethasone group, the expressions of Ptch 1, Aurora A and Cyclin D1 in dexamethasone+vitamin B₁₂group were upregulated in different degrees (all P=0.000), but the expression of Smo had no significant change (P=0.818). There was no significant difference in the expressions of each target protein between the vitamin B₁₂group and the control group (P=0.879, 0.399, 0.645, 0.168). Conclusion: Dexamethasone influences Shh downstream signal transmission and primary cilia depolymerization in the embryonic palatal process of mice, thereby inhibiting the expression of Cyclin D1 and reducing the proliferation of mouse embryonic palatal process cells. Vitamin B₁₂can antagonize the inhibitory effect by up-regulating the content of related factor proteins.