Dissertation
Dissertation > Medicine, health > Internal Medicine > Infectious disease > Fungi and actinomycetes infectious diseases

Natural Product Berberine Inhibits the Mechanism of Research of Aspergillus Fumigatus

Author GaoLei
Tutor WangLi
School Jilin University
Course Pathogen Biology
Keywords Aspergillus fumigatus pathogenic mechanism of Chinese medicinemonomer berberine invasive pulmonary aspergillosis
CLC R519
Type PhD thesis
Year 2012
Downloads 172
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Aspergillus fumigates is saprophyte fungi which is ubiquitous in the environment. As the airborne filamentous fungal pathogen, it is known to be a major cause of lethal lung infections in immunocompromised hosts and allergic asthma in atopic individuals. Invasive pulmonary aspergillosis has high mortality rates(50%-95%), and its incidence has been increasing gradually.Not with standing the increasing need for effective therapy, the range of antifungal agents available is limited, and some of the most effective agents are also toxic. It is necessary to find the new antifungal agents which has good anti-fungal ability and low toxicity. More and more studies showed that it is a good resources to find the antifungal agents.1. The screening of antifungal agents to Aspergillus fumigatusIn this study, we detected the efficacy of20kinds of Chinese medicine for seven Aspergillus fumigatus isolated from clinical patients by microdilution susceptibility method, determination of drug inhibitory effect, the initial screen of five kinds of better antibacterial activity of the monomer, which Berberisthe antibacterial effect of the alkali. Of berberine on42clinical isolates of Aspergillus fumigatus significantly inhibited by increasing the strain number.2. The study of Aspergillus fumigatus treated with Berberine(1) The study of Aspergillus fumigatus biological properties treated with BerberineIn this study, we selected the Aspergillus fumigatus IFM40808to study the mechanism of berberine. Morphological data showed that berberine could inhibit the growth of Aspergillus fumigatus hyphae, spore germination and spore pigment formation. Berberine can inhibit Aspergillus fumigatus hyphae and conidia form distortion by scanning electron microscope observation. In addition, berberine can destroy the continuity of the Aspergillus fumigatus cell wall, membrane partial deletion, and reduced contents of the organelle by transmission electron microscopy observation.(2) Berberine inhibited Aspergillus fumigatus invasionTo further study, we used the Transwell cell chambers established in vitro model of Aspergillus fumigatus invades the cell matrix, and invasive experiments to prove that berberine significantly inhibited the invasive A. fumigatus conidia. After the decline of Aspergillus fumigatus invasive, laser confocal microscopy, FITC nanoparticles and Aspergillus fumigatus mycelium less:in the room next to the cell chamber.We further established the invasive pulmonary aspergillosis model in mice, and treatment with berberine. Prove that berberine treatment of invasive pulmonary aspergillosis in mice survival. Using immunohistochemistry to identify the untreated group of mice lungs was further confirmed by berberine. We detected the protein expression after72h Aspergillus fumigatus infection by Western-blotting. The results showed that berberine could change in the lungs of mice of different groups on the inflammatory signaling pathways associated protein, which proved that no medication treated group inflammatory protein expression was increased in the drug treatment of inflammatory protein expression declined. At the same time, we detected the effect of mice infected with spores, and the results also support the opinion.(3) The combination of berberine with the commonly used antifungal agentsIn this study, we try to examine the effect of the antifungal agent between berberine and anti-Aspergillus fumigatus clinical drugs commonly used in combination. Our studies showed that berberine with itraconazole, voriconazole displayed antagonistic by the checkerboard microdilution experiments; berberine with5-fluorocytosine or terbinafine was no interaction; synergistic with amphotericin B and caspofungin performance. Because of the high incidence of adverse drug reactions the clinical use of amphotericin B is rather limited. With other drug since in combination a lower dose may be used, reducing the risk. This study resulted in the discovery of the theoretical combination of drugs berberine and amphotericin B. It could reduce the doses of amphotericin B. And to reduce the toxicity of amphotericin B in clinical, provides a theoretical basis.(4) The mechanisms of berberine anti-Aspergillus fumigatesWe also find that berberine can inhibit the Real-time PCR berberine can inhibit the expression of the spore pigment, which is regulated gene expression of calcineurin signaling pathways. The secreted proteins of Aspergillus fumigatus extract the drug and non-medication, the role of alveolar epithelial cells and bronchial epithelial cells, further evidence of the application of berberine treatment of Aspergillus fumigatus invasive decline. Itraconazole is the commonly used anti-Aspergillus fumigatus in clinic. Berberine is also used as anti-inflammatory in clinic. We studied the mechanism of antagonistic between berberine and itraconazole, by Real-time PCR and HPLC analysis. Our results showed that berberine could inhibit the gene expression of ergosterol pathway. This is similar to the antifungal mechanism of itraconazole. In conclusion, we selected the anti-Aspergillus fumigatus agents berberine in this study, and showed that while BER was effective in restraining the growth of Aspergillus fumigatus in vitro and in vivo. Our results proved that berberine inhibited Aspergillus fumigatus, and tried to discussed the anti-Aspergillus fumigatus mechanism of berberine. We think that our study will provied a theoretical basis and technical support for clinical application of berberine.

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