Effects of dust particles on autophagy of macrophages / 中国病理生理杂志

ABSTRACT

AIM:To investigate the changes of autophagy of macrophages after phagocytizing dust particles and explore the mechanisms of dust particle-induced autophagy of the cells.METHODS:The bronchopulmonary lymph nodes were collected from patients with lung operation.The paraffin sections were prepared and then stained with Wilder's method.The tissue structures were viewed.Peritoneal macrophages were harvested from rats and then treated with carbon particles.Influences of carbon particles in autophagic activities of macrophages were examined.The ultrathin sections of the lymph nodes and the cells phagocytized carbon particles were prepared.The structures and distribution of phagosomes,autophagosomes and lysosomes were viewed.The apoptotic cells in the dust cells of the lymph nodes and the cells having phagocytized carbon particles were examined using transmission electron microscope and TUNEL staining.RESULTS:In adult lymph nodes,dust particles were deposited significantly in macrophages,collagen fibres and density of microvessels increased.There were autophagosome precursors,autophagosomes,autophagolysosomes as well as phagosomes in the dust cells and the cells phagocytized carbon particles.In autophagosomes,mitochondrion,dust particle or carbon particle were usually observed.There were positive cells by TUNEL staining in the dust cells and the cells phagocytized carbon particles.Nuclear condensation or apoptotic body in the apoptotic cells were observed under transmission electron microscope.CONCLUSION:Deposition of dust particles induces enhancement of autophagic activities and apoptosis of macrophages.Autophagy plays an important role in cleaning dust particles and the injured mitochondria.