牛成牙骨质细胞在体内形成牙骨质样组织的初步研究

目的：培养成牙骨质细胞（cementoblasts,CBs)，观察以CBs自身作为组织工程支架在裸鼠内形成牙骨质的可行性。方法：在矿化培养液中培养新生牛的成牙骨质细胞，使其形成多层CBs作为载体（CBs-made carrier)与CBs混合，植入裸鼠皮下。以CBs与胶原膜载体（collagen carrier) 复合体作为对照。7周后取材并做HE、von Kossa、茜素红及牙骨质附着蛋白单克隆抗体免疫组化染色。结果：CBs在体内可形成牙骨质样矿化组织，中心矿化程度较高，四周有尚未钙化的类牙骨质及CBs包绕，并有牙骨质细胞埋入矿化组织。以CBs自身作为载体所形成的牙骨质较以胶原膜作为载体所形成的牙骨质样组织多。结论：本组分离培养的CBs在体内可形成牙骨质样矿化组织；以多层细胞自身作为载体是一种较理想的生物支架材料。

The in vivo formation of cementum-like tissue by bovine cementoblasts

OBJECTIVE: To test the bovine cementoblasts (CBs) cementum-forming ability in vivo. METHODS: Root fragments of newborn bovine freshly extracted mandibular incisor were cultured routinely and 4th-5th passages of CBs were harvested. CBs were then cultured in the medium supplemented with 50 mg/L alpha-ascorbic acid and 10 mmol/l beta-glycerolphosphate to form a thick layer as tissue engineering scaffold for cementum formation. Collagen membrane was used as control scaffold. 2 x 10(6) cells were attached to the CBs-made carrier as well as collagen membrane scaffolds and transplanted subcutaneously into immunodeficient mice. Transplants were harvested at 7th week. Histological sections were stained with HE, alizarin red S and van Kossa methods as well as monoclonal Ab against bovine cementum attachment protein (CAP). RESULTS: CBs-made scaffold supported more cementum-like tissue (CLT) formation than collagen-made scaffold. The CLT formed on CBs scaffold was partly calcified with embedded cells. Uncalcified cementoid-like material could be seen on the surface and was encircled by cubical CB-like cells. The CLT was also positive to CAP and van Kossa staining. CONCLUSIONS: These results suggest that the bovine CBs can form cementum-like tissue. The cell-made carrier is a better scaffold than collagen membrane.