title: PMN apoptosis and its relationship with the lung injury after chest impact trauma.
abstract: BACKGROUND
  Polymorphonuclear neutrophil (PMN), one of the most important inflammatory cells, functions throughout the initiation, progression and resolution of inflammation. This study aimed at investigating the relationship between PMN apoptosis and the lung injury after chest impact trauma.
  
  
  METHODS
  PMNs were purified from rabbits subjected to the chest impact trauma and their apoptosis, necrosis, survival and respiratory burst were detected by flow cytometry. Meanwhile, lactate dehydrogenase and (LDH) [Ca2+]i were measured.
  
  
  RESULTS
  The delayed apoptosis of PMNs in bronchoalveolar lavage fluid was observed from 2 hours to 12 hours after trauma, and viable cells increased. Respiratory burst of PMNs in bronchoalveolar lavage fluid was increased significantly from 2 hours with the peak at 8 hours. Meanwhile, lactate dehydrogenase in bronchoalveolar lavage fluid was higher than that in control (P < 0.05) from 4 hours to 24 hours, and intracellular free Ca2+ in PMN was increased temporarily.
  
  
  CONCLUSIONS
  Retention of PMN in tissues and the abnormality in apoptotic pathway inevitably generate persistent activation of PMN and excessive release of toxic substances, resulting in tissue injury. The temporary increase of intracellular free Ca2+ may be responsible for the delayed apoptosis of PMN.
authors.affiliation: Institute of Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042, China. liu0916@mail.china.com
authors.forename: Ren
authors.initials: R
authors.lastname: Liu
authors.forename: Shuang-ding
authors.initials: SD
authors.lastname: Li
authors.forename: Jia-xin
authors.initials: JX
authors.lastname: Min
authors.forename: Nan
authors.initials: N
authors.lastname: Xiao
authors.forename: Qi-sheng
authors.initials: QS
authors.lastname: Jiang
authors.forename: Kun-lun
authors.initials: KL
authors.lastname: Tian
authors.forename: You-fang
authors.initials: YF
authors.lastname: Diao
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D055370:Lung Injury; D009504:Neutrophils / Q000502:physiology*; D011817:Rabbits; D016897:Respiratory Burst / Q000502:physiology; D013898:Thoracic Injuries / Q000150:complications*