Hypoxia promotes the formation of Cryptococcus neoformans biofilms / 医学研究生学报

ABSTRACT

Objective There is a lack of information on the effect of hypoxia on the virulence of Cryptococcus neoformans . This study was to construct a Cryptococcus neoformans bilfilm model in vitro and observe the influence of hypoxia on the biofilm forma-tion. Methods We constructed a Cryptococcus neoformans biofilm model in vitro in 24-well and 96-well microculture plates using DMEM culture medium at the oxygen concentrations of 21%( normoxia ) and 1% ( hypoxia ) .We collected the Cryptococcus neofor-mans biofilms at 2, 4, 8, 12, 24, 48, and 72 hours after culturing and observed their thickness , structure, and growth activity in the two different oxygen conditions by light microscopy , confocal laser scanning microscopy , and MTT assay . Results The Cryptococcus neoformans biofilm model was successfully constructed in the conditions of both hypoxia and normoxia .The processes of biofilm forma-tion in the two conditions were similar , involving adhesion , aggregation , micro-colony formation , and biofilm maturation , with the ulti-mate biofilm thickness of about 16 μm.The cell density and growth activity of the biofilms increased with the extension of incubation time, gradually stabilized with their maturity , and both were relatively higher at 1%than at 21%oxygen concentration . Conclusion The abilities of Cryptococcus neoformans biofilm formation vary with different oxygen concentrations , and hypoxia can promote the for-mation of Cryptococcus neoformans biofilms .