Effect Of Yili Dark Propolis On Mutans Streptococci Metabolism In Both Planktonic And Biofilm State, In Vitro Study

Objective:To find out possible mechanism of ethanol extract of Yili dark Propolis’s effect on inhibiting acid production and saccharide formation of cariogenic Mutans Streptococci in different states by means of comparing the way EEP and NaF effecting bacteria’s lactate dehydrogenase(LDH) activity and transcription of related coding gene.Methods:Incubate Streptococcus mutans and Streptococcus sobrinus in both planktonic and biofilm state, set BHI culture medium which containing various concentration of EEP;BHI culture medium which containing 50mg/L NaF, and BHI culture medium only as study group, positive control group and negative control group respectively, then interact with objective bacterium in different state for 18hours. (1)Coenzyme I reduced method was used to assay LDH activity of each group. (2) Obtain crude extract from supernatant, calculate GTF activity by anthrone method.(3) Total RNA was extracted by Trizol, then assay transcription level of 1dh by means of RT-qPCR.(4)Extract total RNA by Trizol, use Rt-qPCR method to assay gtfB, gtfC, gtfDat transcription level.Results:(1)Significant inhibition of LDH activity found between all study groups and NaF group when compare to negative control in both planktonic and biofilm of Streptococcus mutans and Streptococcus sobrinus after interaction (P<0.05).(2)As for planktonic state of Streptococcus mutans and Streptococcus sobrinus, after interaction with all groups, significant down-regulation of ldh was detected in both study group and NaF group (P<0.05).1dh down-regulation ratio in study group was greater than NaF group (P<0.05);To the state of biofilm, Streptococcus mutans after interaction with all groups, study groups contain MBEC,1/2MBEC,1/4MBEC EEP significantly down-regulate ldh expression compared to the negative control (P<0.05);For Streptococcus sobrinus biofilm, all concentrations of EEP in study group significantly down-regulate ldh expression compared to the negative control (P<0.05). While NaF group in neither Streptococcus mutans and Streptococcus sobrinus didn’t show difference to negative control (P>0.05) (4)In both planktonic and biofilm state of Streptococcus mutans, expression of gtfB, gtfC, gtfDweren’t affected by EEP in study group, as for positive control group, NaF upregulated the gtfB expression.Conclusion:Possible mechanism of Yili dark Propolis inhibiting acid production of Mutans Streptococci is inhibiting LDH activity as well as down regulating ldh gene expression in both planktonic and biofilm state.Propolis do little affect to the GTF activity and gtfs gene expression.