淀粉与食用糖交互作用的致龋性初探

目的　初步探讨淀粉与蔗糖、高果糖玉米糖浆（high- fructose corn syrup ，HFCS）的交互作用对变形链球菌致龋毒力的影响。方法　变形链球菌UA159培养于质量浓度均为1%的蔗糖、淀粉和HFCS组成的双糖和三糖BHI培养基中，三种单一糖源作为对照，于培养的6个时间点测量每组的pH值，计算ΔpH；96孔微孔板培养20h后采用结晶紫比色法比较7组的粘附力。结果 蔗糖+HFCS和三糖组产酸速度较快，ΔpH明显大于蔗糖+淀粉和淀粉+HFCS组（P<0.05）。4组实验组的粘附性存在统计学差异（P<0.01），蔗糖+淀粉组的粘附性最强，三糖组的粘附性强于蔗糖+HFCS组，淀粉+HFCS组最弱。结论　淀粉和蔗糖、HFCS间的交互作用会影响变形链球菌产酸、粘附和生物膜的形成，从而导致其致龋性的改变。

A preliminary study on the cariogenicity of the interaction between starch and dietary sugar

Objective　 To investigate the effect of interactions between starch，sucrose and HFCS on the cariogenicity of streptococcus mutants. Methods　 Streptococcus mutants UA159 was cultured in BHI medium containing two or three kinds of sugar——1%starch，sucrose，and HFCS ，with the single sugar source used as control. The pH of each culture was measured to assess acidogenicity. Crystal violet assay was employed to determine the ability of adherence. Results　 The pH in sucrose+HFCS and sucrose+starch+HFCS media was decreased faster than that in sucrose+starch and starch+HFCS media( p<0.05). The adhesion of S. mutans in sucrose+starch media was significantly higher than that in other media (p < 0.05). The group containing three sugars has better adhesive ability compared with sucrose + HFCS. The adherence in starch+HFCS media was significantly weaker than that in other media (p < 0.05). Conclusions　 The interaction between starch，sucrose and HFCS can affect the formation of acid，adhesion and biofilm of S.mutants, resulting in the change of cariogenicity.