长期微塑料暴露对小鼠肠道炎症水平及菌群的影响

Effect of Long-term Exposure to Microplastics on Intestine Inflammatory Level and Gut Microbiota in Mice

长期暴露微塑料会影响机体免疫功能进而发生炎症反应,其致炎机制有待研究。本研究以C57BL/6J小鼠为研究对象,将直径为1μm和5μm的单分散荧光聚苯乙烯微球用灌胃的方法对小鼠进行慢性暴露,30周后探究微塑料长期暴露对小鼠炎症细胞因子、肠组织形态以及菌群的影响。结果表明,与正常对照组相比,微塑料显著增加了小鼠血清促炎细胞因子1L-1β水平,小肠和结肠组织炎症细胞浸润明显;暴露组肠菌群α多样性显著降低,Actinobacteria显著下降;属水平上Clostridia_UCG-014和Bifidobacterium等有益菌的相对丰度显著下降,Lactobacillus与炎症细胞因子TNF-α、1L-1β呈显著负相关。综上,微塑料长期暴露可能通过影响肠道有益菌丰度,降低肠道菌群的α多样性,导致肠道菌群结构紊乱,从而增加小鼠炎症因子的表达水平,促进小鼠肠道炎症反应。

Long-term exposure to microplastics might affect the immune function and lead to inflammation.The mechanism needs to be investigated.In this study,C57BL/6J mice were exposed to monodisperse fluorescent polystyrene microspheres with diameters of 1μm and 5μm by gastric gavage chronically.The effects of persistent exposure to microplastics on inflammatory cytokines,intestinal tissue morphology,and gut microbiota of the mice were studied after thirty weeks.The results showed that compared to the control group,microplastics increased the level of 1L-1βin serum significantly,and the inflammatory cell infiltration in the intestine and colon was obvious;the alpha diversity of the gut microbiota in the exposure group was significantly reduced,and the relative abundance of Actinobacteria was significantly decreased;at the genus level,the relative abundance of probiotics such as Clostridia_UCG-014 and Bifidobacterium decreased significantly,and Lactobacillus showed a significant negative correlation with TNF-αand 1L-1β.In conclusion,long-term exposure to microplastics reduced the diversity of gut microbiota,affected the abundance of intestinal probiotics and caused the disturbance of bacterial composition.It also increases the expression levels of inflammatory factors and induces intestinal inflammatory responses in mice.