【作者】 孙继军；

【导师】 姜广水；

【作者基本信息】 山东大学 ， 口腔临床医学， 2005， 硕士

【摘要】 龋病是一种多因素感染性疾病,变形链球菌(Streptococcus mutans)是主要的致龋菌,其致龋机制在于它能粘附于牙面、产酸和耐酸,因此,抑制变形链球菌的生长是预防龋病的重要途径之一。本校生命科学院研究者从土壤中筛选了一株灰色链霉菌,体外实验发现,它产生的溶菌酶能够明显抑制变形链球菌的生长,为防龋研究开辟了新途径。本实验建立了定菌鼠模型,以不同的药物喂养大鼠,通过3种实验方法观察灰色链霉菌RX-17溶菌酶对变形链球菌在动物口腔内生长、繁殖及龋病发生、发展的影响,并比较其防龋效果与氟化钠的差异,初步探讨灰色链霉菌RX-17溶菌酶用于防龋的可能性。 目的:研究灰色链霉菌RX-17溶菌酶在动物口腔内对致龋菌-变形链球菌的生长、繁殖及龋病发生、发展的抑制作用,为该溶菌酶用于人类龋病防治提供理论依据。 方法:给大鼠口腔接种变形链球菌,并饲以致龋饲料2000~#,分别喂以大鼠蒸馏水、氟化钠水溶液、灰色链霉菌RX-17溶菌酶液,测定牙菌斑pH值,菌斑取样、细菌培养计数,取上下颌骨进行Keyes龋齿计分。 结果:灰色链霉菌RX-17溶菌酶组大鼠牙菌斑pH值高于蒸馏水组(P<0.05),低于氟化钠组(P<0.05)。变形链球菌计数在灰色链霉菌RX-17溶菌酶组少于蒸馏水组(P<0.01)和氟化钠组(P<0.05)。Keyes计分结果显示,灰更多还原

【Abstract】 Dental caries is a bacterial infectious disease influenced by multiple factors. Streptococcus mutans(S. mutans) has been implicated as one of the most important pathogenic organisms. The cariogenic mechanism is that S. mutans can adhere to the tooth surfaces, be acidogening and be aciduring. So to inhibit S. mutans growth is an important path to the prophylaxis of the disease. Experiment in vitro revealed that bacteriolytic enzyme derived from Streptomyces griseus RX-17, which was isolated from soils, can inhibit S. mutans growth effectively. The RX-17 bacteriolytic enzyme can be used for prophylaxis of dental caries in human.Objective: To investigate the effect of bacteriolytic enzyme derived from Streptomyces griseus RX-17 on the growth of a cariogenic microbe S. mutans and the development of caries in rats.Methods: Wistar rats were fed with cariogenic forage 2000 , and inoculated to the mouths with S. mutans. The rats were divided into 3 groups and administered with distilled water, sodium fluoride, and RX-17 bacteriolytic enzyme respectively. The effect of RX-17 bacteriolytic enzyme on the growth of S. mutans and caries development were observed by measuring plaque pH, plaque bacteria count and Keyes scoring method.Results: Plaque pH of the RX-17 bacteriolytic enzyme group was significantlyhigher than that of the distilled water group (P<0.05) , but lower than that of the sodium fluoride group (P<0.05). The number of S. mutans in the RX-17 bacteriolytic enzyme group was significantly less than in both the distilled water group (P<0.01) and the sodium fluoride group (P<0.05) . According to Keyes scores, the number of RX-17 bacteriolytic enzyme group at E and Ds levels was significantly less than that of the distilled water group (P<0.01) , but there was no significant difference between the RX-17 bacteriolytic enzyme group and the sodium fluoride group (P> 0.05) , Dm and Dx levels dental caries only could be seen in the distilled water group.Conclusions: RX-17 bacteriolytic enzyme could dissolve the S. mutans in rats and make it loss the ability of growth and reproduction. It also could inhibit the development of caries and such effectiveness was as much as that of the sodium fluoride. Morever, unlike fluoride it is without toxic side effect to the human body. RX-17 bacteriolytic enzyme may be used as a safely and effectively anti-caries method.更多还原