Effect Of Calcitionin On Cranial Osteoblasts From Neonate Rats In Vitro

BACKGROUND: Calcitionin ,a drastic osteoclast inhibitor,can inhibit bone resorption directly, quickly and extensively. Recently some scholars reported that calcitionin also can promote union of fracture.OBJECTIVE: To observe the effect of calcitionin on cranial osteoblasts (0B) from neonate rats in vitro and the effect of ERK-MAPK in the above process,to provide rationale for a more extensive and reasonable clinical use of calcitionin. DESIGN,TIME AND SETTING: The grouping controlled experiment was accomplished in pharmacology lab of NanJing Medical University from July 2007 to May 2008.MATERIALS: Ten SD rats were recruited,1 day old,regardless of gender. Calcitionin was the product of Switzerland Novartis Company. METHODS: Isolate the osteoblasts from craniums of neonate rats within 24 hours after its born and culture the osteoblasts in vitro. The second generation osteoblasts were co cultured with calcitionin at different concentrations: blank group, 0.01ng/ml calcitionin group,0.1ng/ml calcitionin group,1ng/ml calcitionin group, and another 1ng/ml calcitionin group were added with U0126 , a specific inhibitor of ERK-MAPK,in advance. MAIN OUTCOME MEASURES: The ability of cell proliferation,differentiation and mineralization were evaluated by MTT,PNPP and mineralized nodes staining respectively;The level of cbfa1mRNA in different groups were measured by RT-PCR and the phosphor-ERK1/2 expression of the OB were analyzed by western blotting. RESULTS: Calcitionin can improve the ability of OB proliferation,differentiation,mineralization and the expression of cbfa1 mRNA in dose-dependent manner. The effect of the 0.1ng/ml calcitionin group and the 1ng/ml calcitionin group had significant effect(P<0.05);The expression of the phospho-ERK1/2 was also related to the calcitionin concentration. moreover,all the effects above were blocked by U0126.CONCLUSION: Calcitionin improves the proliferation,differentiation and mineralization ability of OB in vitro by regulating the cbfa1mRNA expression ,which is related to the signal pathway of ERK-MAPK.