壳聚糖体外抗白念珠菌生物膜作用的初步研究

目的观察壳聚糖对白念珠菌生物膜形成的影响,探讨其可能的作用机制。方法 XTT减低法评价壳聚糖对白念珠菌生物膜形成及黏附的影响,镜下观察壳聚糖对白念珠菌生物膜形态的影响;实时定量RT-PCR法观察壳聚糖对白念珠菌的Ras信号通路因子CDC35、PDE2、EFG1和HWP1的基因表达的影响。结果低浓度(0.02 mg/mL)和高浓度(0.32mg/mL)壳聚糖对白念珠菌生物膜形成的抑制率分别为(19.6±1.2)%和(96.96±0.6)%,0.16 mg/mL浓度下壳聚糖对早期(0 h)、中期(12 h)和成熟期(48 h)的生物膜抑制率分别为(78.6±0.5)%、(54.4±0.9)%和(41.1±1.1)%,不同浓度的壳聚糖对各黏附阶段的白念珠菌细胞黏附均有抑制作用,壳聚糖可剂量依赖性地下调白念珠菌生物膜Ras信号通路基因CDC35、EFG1和HWP1的表达水平,上调Ras信号通路抑制剂PDE2的基因表达水平(P<0.05)。结论壳聚糖可能通过影响Ras信号通路及抑制细胞黏附而对白念珠菌生物膜的形成具有抑制作用。

In vitro activity of chitosan against Candida albicans biofilm

Objective To investigate inhibitory effect of chitosan on Candida albicans biofilm, and to discuss the possible mech- anism. Methods XTT reduction assay was used to investigate the influence of different concentrations of chitosan on Candiia albicans biofilm formation and cell adherence. Microscopic examination was conducted to assess the effect of chitosan on morphogene- sis of Candida albicans biofilm. The mRNA expressions of CDC35, PDE2, EFG1 and HWP1 were measured by realtime RT-PCR with different concentrations of chitosan. Results The inhibition rates of chitosan against Candida albicans biofilm formation were （ 19.6 ± 1.2） % by 0.02 mg/mL and （96.96 ± 0.6） % by 0. 32 mg/mL. Chitosan （0.16 mg/mL） inhibited different stages of biofilm, with （78.6 ± 0.5 ） %, （54.4 ± 0.9） % and （41.1 ± 1.1 ） % inhibition rates when cells was treated for 0 h, 12 h and 48 h, respec- tively. Chitosan from 0.02 mg/mL to 0.32 mg/mL showed distinct inhibitive effect on adhesion to Candida albicans cultured for 30 min,60 min,90 min and 120 min （ P 〈 0.05 ）. The mRNA expression levels of CDC35, EFG1 and HWP1 were decreased in Chi- tosan treated cells, while the PDE mRNA level was increased. Conclusion Chitosan may inhibit the Candida albicans biofilm for- mation through regulating Ras signaling pathway and cell adherence.