变异链球菌致龋性及酸性压力对其HtrA表达情况的影响

Influence of HtrA Expression on the Cariogenicity and the Acid Stress of Streptococcus Mutans

目的:探讨变异链球菌株HtrA的表达与其致龋性和耐酸性的关系。方法:收集了不同龋敏感性儿童口腔分离的变异链球菌共36株(高、低、无龋各12株),通过RT-PCR的方法对所有菌株HtrA的mRNA的表达水平进行了检测;此外,还检测了在分别含有10、20mmol/L乳酸的培养基中生长的变异链球菌UA159菌株HtrA mR-NA的表达变化。结果:高龋、低龋及无龋儿童口腔变异链球菌临床分离株HtrA mRNA表达存在差异,高龋组>低龋组>无龋组,差异具有统计学意义(P<0.01);酸性环境下变异链球菌中HtrA mRNA的表达水平也发生了明显上调(P<0.01)。结论:HtrA基因的表达与变异链球菌的致龋性和耐酸性有着一定的相关性。

Objective： To explore the relationship between the HtrA expression of Streptococcus mutans and its cariogenicity and acid resistance. Methods： A totally of 36 isolates of Streptococcus mutans were obtained from chil- dren with different degree of dental caries （High-, low- and free-caries are 12 strains, respectively）, and the expression of HtrA mRNA of all strains were det＇ected by RT-PCR method. Additional, the HtrA mRNA expres sion of S. mutans UA159 under lactic acid conditions were observed. Results： There was a difference among the HtrA mRNA expression in S. mutans isolates form Children with different degree of dental caries, High-caries group〉low-caries group〉 free-caries group, and the difference was statistically significance （P〈0.01）. The HtrA mRNA expression level of S. mutans were up-regulated under acid conditions （P〈0.01）. Conclusion： The HtrA expression of S. mutans was related to its cariogenicity and acid resistance.