Inhibitory effect of methylene blue mediated photodynamic therapy combined with berberine on Porphyromonas gingivalis in vitro / 国际生物医学工程杂志

ABSTRACT

Objective:To investigate the in vitro inhibitory effect of methylene blue mediated photodynamic therapy (PDT) combined with berberine on Porphyromonas gingivalis (P.g). Methods:P.g was cultured until the middle to late log phase, and methylene blue was added to P.g suspension at different mass concentrations for 5 min, and a laser (wavelength 660 nm, power 140 mW/cm 2) was irradiated for 2 min to find the optimal concentration of methylene blue combined with the laser for in vitro inhibition of P.g. The effect of methylene blue mediated PDT on the in vitro inhibition of P.g and the effect of berberine on the growth curve of P.g were observed. The inhibitory effect of methylene blue mediated PDT and berberine on P.g was investigated by successive combined applications. The effect of methylene blue mediated PDT on P.g morphology was observed by scanning electron microscopy. The absorption peaks of each component were measured by ultraviolet spectrophotometer. Results:The best inhibition was achieved at a methylene blue mass concentration of 24.414 1 μg/ml under 660 nm laser excitation. The differences were statistically significant in both the methylene blue and PDT groups compared with the control group (all P<0.001). 0.05 mg/ml berberine had an inhibitory effect on the planktonic bacteria of P.g. After P.g was treated with methylene blue mediated PDT, the bacterial cell walls were crumpled into clusters. Compared with the control group, the number of colonies was reduced in the 0.05 mg/ml berberine group, and the difference was statistically significant ( P<0.01). The difference between the 0.05 mg/ml berberine + light group and the control group was not statistically significant ( P>0.05). When PDT was combined with berberine, there was a synergistic inhibitory effect on P.g. PDT followed by berberine shows a better inhibitory effect on bacteria, and the differences were statistically significant (all P<0.01). After the berberine treatment, the bacterial surface became smooth, and the length of the bacterial body increased compared with the control group. Conclusions:Methylene blue mediated PDT has an inhibitory effect on P.g. When combined with berberine, it has a synergistic inhibitory effect on P.g., and the inhibition effect is better when PDT is applied first and then berberine is applied in combination.