氟化鈉對乳牙牙髓細胞生長以及礦化基因表現的調控

Abstract

氟素在牙科公共衛生上的應用已經持續很長的一段時間。氟對於預防孩童齲齒的發生是很重要，也是很有效的一個藥物。另一方面因為氟可以刺激骨母細胞的增生以及刺激骨組織的形成，氟素也被拿來當作治療骨質疏鬆症。在即將脫落的乳牙牙髓組織中，存在多能力的幹細胞。而這些幹細胞具有高度增生及分化能力的特性，並且可分化成為牙本質母細胞。然而氟對於乳牙牙髓細胞作用的毒性或是其作用的角色都尚未清楚。所以本實驗的主要目的是觀察氟化鈉對於體外培養乳牙牙髓細胞其生長能力和礦化基因表現的影響 。 乳牙牙髓細胞是以2.5x104cell/cm2的密度培養於含氟化鈉濃度為0, 10-6, 10-5, 10-4, 5x10-4及10-3M之培養液來進行MTT測試觀察細胞生長的情形。另外將乳牙牙髓細胞同樣以密度培養於0, 10-6, 10-5, 10-4 及 5x10-4M並和培養於牙本質細胞誘導礦化培養液中的細胞進行鹼性磷酸酶(alkaline phosphatase)、鈣化能力以及礦化基因表現的比較。 在MTT測試中，發現到當氟化鈉的濃度為10-3M，乳牙牙髓細胞在培養的第1天以及第3天其細胞生長的活性是受到限制。然而在培養的第10天，在含氟化鈉培養基的細胞，其生長活性高於控制組。在鹼性磷酸酶活性試驗中，在培養的第5天和第7天，含氟化鈉培養基的細胞，其活性都低於控制組；然而到了第14天，有接受氟化鈉刺激的細胞，其活性超越控制組。在礦化基因表現，在培養第7天和第10天，鹼性磷酸酶基因的表現低於控制組和牙本質細胞誘導礦化組；於培養第14天，鹼性磷酸酶基因的表現則會高於控制組。在骨鈣蛋白基因表現，於培養的第7天，於含氟化鈉培養基中的細胞其表現較弱；然而第14天含有氟化鈉培養基中的細胞基因的表現則高於控制組。由以上的結果可以推論，氟化鈉確實會影響乳牙牙髓細胞的生長以及礦化表現，氟化鈉對於調控乳牙牙髓細胞生長及礦化基因的表現仍需做進一步的研究。

The use of fluorides in dental public health programs has a long history. Fluoride is an important and effective factor for reducing the caries incidence in children. Fluoride also increases proliferation of osteoblasts and stimulates bone formation. Exfoliated human deciduous tooth contains multipotent stem cells in the pulp tisuue. These cells were identified to be a population of highly proliferative, clonogenic cells capable of differentiating into odontoblasts. However the cellular and molecular pathways of fluoride toxicity in pulp cells derived exfoliated deciduous teeth are not very well understood. The objective of the present study was to evaluate the effects of sodium fluoride (NaF) on pulp cells derived from exfoliated deciduous teeth cultured in vitro. Pulp cells at 2.5x104cell/cm2 were incubated in vitro with NaF at 0, 10-6, 10-5, 10-4, 5x10-4 and 10-3M and MTT test was examined. Pulp cells at 2.5x104cells/cm2 in density were also incubated in vitro with NaF at 0, 10-6, 10-5, 10-4 and 5x10-4M compared to odontogenic induction medium, and then the ALP activity, calcification and mineralization were examined. A cell based quantitative evaluation of the MTT assay showed that NaF at concentration of 10-3M arrested cell growth on day 1 and day 3. Whereas the MTT assay showed that higher proliferative rate treated with NaF versus control on day 10. Alkaline phosphatase activity decreased in cells treated with NaF on day 5 and day 7 versus control. On day 14, cells treated with NaF had higher alkaline phosphatase activity than control. The gene of alkaline phosphatase expression in cells treated with NaF decreased on day 7 and day 10 versus control and induction group but enhanced on day 14. Osteocalcin expression of NaF treated cells decreased on day 7 versus control but enhanced on day 14. In conclusion, results of this study indicated that NaF modulates proliferation and mineralization pulp cells derived from exfoliated deciduous teeth proliferation and mineralization. This findings suggest that NaF may play a significant role in pulp cells physiology.