[Biologic effects of advanced oxidative protein products on the human gingival fibroblasts].

OBJECTIVE: To investigate the effects of advanced oxidative protein products (AOPP) on the proliferation, apoptosis and matrix metalloproteinase-1 (MMP-1) synthesis of the human gingival fibroblast (HGF). To explore the possible mechanism of the periodontal destruction acceleration in diabetes through AOPP-mediated oxidative stress. METHODS: HGF were isolated by both tissue explant cultivation technique and enzyme digestion method. The culture media with 5, 50, 100 mg/L AOPP-HAS were added into each experimental group, but the culture media in the control group didn't contain AOPP-HAS. MTT colorimetric assay and ELISA were used to measure the changes of HGF proliferation and the levels of MMP-1 protein from HGF at different time periods, respectively. Seventy-two hours after co-culture with 50 mg/L AOPP-HSA, cell apoptosis was detected by flow cytometry with Annexin V/PI staining. RESULTS: Compared to the control group, the growth inhibition rate of HGF in 5, 50, 100 mg/L AOPP-HSA group was significantly different (P < 0.05). The peak value appeared at 48 hours of co-culture [(19.01 +/- 6.28)%, (30.48 +/- 5.75)%, (39.75 +/- 4.60)%, respectively]. There was a dose-dependent relationship between the growth inhibition rate and AOPP-HSA. No significant difference was detected on the apoptotic level between experimental group and the control (P > 0.05). The MMP-1 synthesis in 0.5, 5, 50, 100 mg/L AOPP-HAS group [(55.61 +/- 1.06), (65.78 +/- 4.04), (79.24 +/- 3.09), (89.76 +/- 28.88) mg/L, respectively] was significantly higher than that in the control [(34.90 +/- 3.15) mg/L] after 72 hours co-culture (P < 0.05). There was a dose-dependent relationship between MMP-1 and AOPP-HSA. CONCLUSIONS: AOPP may inhibit the proliferation of HGF and such effect was not achieved through apoptosis. AOPP may increase collagen degradation by promoting MMP-1 synthesis and thus may accelerate periodontal destruction process in diabetes.

[MGB probes detect Streptococcus mutans and Streptococcus sobrinus in real time].

OBJECTIVE: To detect and distinguish Streptococcus mutans (S. mutans) and Streptococcus sobrinus (S. sobrinus) quickly in epidemiology and investigate the distribution of S. mutans in the oral of children with rampant caries. METHODS: Designed minor groove binder (MGB) probes according to the gtf gene of S. mutans and S. sobrinus. Detected 9 reference strains of Streptococcus mutans group by MGB probes in real time and after cultivation. Evaluated the results of these two methods. 92 dental plaques from pre-school children with rampant caries were detected in real time with MGB probes. RESULTS: The primers could amplify the target sequences specificity and distinguished S. mutans and S. sobrinus from each other using MGB probes. Though the fluorescence occurred earlier in S. mutans than in S. sobrinus, they had the same results in nature. In 92 children with rampant caries, the detective ratio of S. mutans was 96.7% and that of S. sobrinus was 32.6%. All the samples which could detect S. sobrinus were positive for S. mutans. CONCLUSION: The primers and probe designed from gtf genes of S. mutans and S. sobrinus can amplify the target sequence and distinguish them from each other in real time.