title: [Macrophage apoptosis and the levels of interleukin-1 and interleukin-8 in the rats exposed to silica].
abstract: OBJECTIVE
  To study the roles of macrophage apoptosis, IL-1, and IL-8 in the pathogenesis of rat pulmonary fibrosis induced by silica.
  
  
  METHODS
  Forty eight male Wistar rats were divided into the 4 control groups (24 rats) and 4 experimental groups (24 rats). Rats in the control groups were treated with 1 ml normal saline by trachea instillation, whereas the rats in experimental groups were exposed 1 ml silica suspension (100 mg/ml) by trachea instillation for 1, 7, 14 and 28 days, respectively. Six rats of each group were sacrificed, then the bronchoalveolar lavage fluid and lung tissues were collected, respectively. Pulmonary inflammation, fibrosis and other pathological changes were detected with H.E. staining. Morphological changes of the early stage apoptosis in macrophages were detected with transmission electron microscope (TEM). The early apoptosis rates of macrophages in BALF were also assessed using Annexin V-FITC/PI kit. The IL-1 and IL-8 levels of serum were measured with the ELISA.
  
  
  RESULTS
  The apoptotic rates (11.48% +/- 0.24%, 16.03% +/- 0.68%, 15.53% +/- 1.07%, 18.92% +/- 2.70%, respectively) of macrophage in the experimental groups increased obviously with time, as compared to the controls (5.47% +/- 2.06%, 6.39% +/- 0.215, 9.07% +/- 0.61% and 8.54% +/- 0.16%, Respectively) (P < 0.05). The IL-1 levels of serum in the experimental groups were 23.64 +/- 0.84, 23.38 +/- 1.10, 22.21 +/- 0.86 and 24.29 +/- 1.31 pg/ml, respectively, which were significantly higher than those (18.52 +/- 1.23, 18.40 +/- 1.6, 17.92 +/- 2.21 and 18.53 +/- 2.64 pg/ml, respectively) in the control groups (P < 0.05) without time-effect relationship. The serum IL-8 levels on the 1st, 7th and 14th days in the experimental groups were 21.32 +/- 1.44, 21.90 +/- 2.08 and 22.00 +/- 2.80 pg/ml, respectively, which were significantly higher than those (17.69 +/- 1.09, 16.98 +/- 2.09 and 17.54 +/- 1.62 pg/ml, respectively) in the control groups (P < 0.05).
  
  
  CONCLUSIONS
  The early macrophage apoptosis and changes of IL-1 and IL-8 may in lungs may play an important role in the development of pulmonary fibrosis induced by silica.
authors.affiliation: School of Public Health Hebei United University, Tangshan 063000 China.
authors.forename: Yu-Lan
authors.initials: YL
authors.lastname: Jin
authors.forename: Wen-Li
authors.initials: WL
authors.lastname: Zhang
authors.forename: San-Qiao
authors.initials: SQ
authors.lastname: Yao
authors.forename: Xue-Yun
authors.initials: XY
authors.lastname: Fan
authors.forename: Ying-Jun
authors.initials: YJ
authors.lastname: Xu
authors.forename: Yu-Ping
authors.initials: YP
authors.lastname: Bai
authors.forename: Ju-Xiang
authors.initials: JX
authors.lastname: Yuan
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D004195:Disease Models, Animal; D007375:Interleukin-1 / Q000097:blood; D016209:Interleukin-8 / Q000097:blood; D016676:Macrophages, Alveolar / Q000166:cytology* / Q000187:drug effects*; D008297:Male; D011658:Pulmonary Fibrosis; D051381:Rats; D017208:Rats, Wistar; D012822:Silicon Dioxide / Q000633:toxicity*; D012829:Silicosis / Q000097:blood / Q000473:pathology
chemical_list: D007375:Interleukin-1; D016209:Interleukin-8; D012822:Silicon Dioxide