title: IL-10 inhibits inflammatory cytokines released by fetal mouse lung fibroblasts exposed to mechanical stretch.
abstract: BACKGROUND
  Mechanical ventilation plays an important role in the pathogenesis of bronchopulmonary dysplasia. However, the molecular mechanisms by which excessive stretch induces lung inflammation are not well characterized.
  
  
  OBJECTIVE
  In this study, we investigated in vitro the contribution of lung mesenchymal cells to the inflammatory response mediated by mechanical stretch and the potential protective role of IL-10.
  
  
  METHODS
  Fetal mouse lung fibroblasts isolated during the saccular stage of lung development were exposed to 20% cyclic stretch to simulate mechanical injury. The phenotype of cultured fibroblasts was investigated by red oil O and alpha-smooth muscle actin (α-SMA) staining. Cell necrosis, apoptosis, and inflammation were analyzed by lactate dehydrogenase release, cleaved caspase-3 activation and release of cytokines and chemokines into the supernatant, respectively.
  
  
  RESULTS
  First, we characterized the phenotype of the cultured fibroblasts and found an absence of red oil O staining and 100% positive staining for α-SMA, indicating that cultured fibroblasts were myofibroblasts. Mechanical stretch increased necrosis and apoptosis by two- and three-fold, compared to unstretched samples. Incubation of monolayers with IL-10 prior to stretch did not affect necrosis but significantly decreased apoptosis. Mechanical stretch increased release of pro-inflammatory cytokines and chemokines IL-1β, MCP-1, RANTES, IL-6, KC and TNF-α into the supernatant by 1.5- to 2.5-fold, and administration of IL-10 before stretch blocked that release.
  
  
  CONCLUSIONS
  Our data demonstrate that lung interstitial cells may play a significant role in the inflammatory cascade triggered by mechanical stretch. IL-10 protects fetal fibroblasts from injury secondary to stretch. Pediatr. Pulmonol. 2011; 46:640-649. © 2011 Wiley-Liss, Inc.
authors.affiliation: Department of Pediatrics, Women and Infants Hospital of Rhode Island, 101 Dudley Street, Providence, Rhode Island 02905, USA.
authors.forename: Renda L
authors.initials: RL
authors.lastname: Hawwa
authors.forename: Michael A
authors.initials: MA
authors.lastname: Hokenson
authors.forename: Yulian
authors.initials: Y
authors.lastname: Wang
authors.forename: Zheping
authors.initials: Z
authors.lastname: Huang
authors.forename: Surendra
authors.initials: S
authors.lastname: Sharma
authors.forename: Juan
authors.initials: J
authors.lastname: Sanchez-Esteban
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D002478:Cells, Cultured; D016207:Cytokines / Q000037:antagonists & inhibitors* / Q000378:metabolism; D005260:Female; D005333:Fetus; D005347:Fibroblasts / Q000502:physiology*; D066298:In Vitro Techniques; D016753:Interleukin-10 / Q000494:pharmacology*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008168:Lung / Q000196:embryology*; D008648:Mesoderm / Q000166:cytology; D051379:Mice; D008810:Mice, Inbred C57BL; D009336:Necrosis; D010641:Phenotype; D053701:Receptors, Interleukin-10 / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013314:Stress, Mechanical
chemical_list: C558396:Acta2 protein, mouse; D000199:Actins; D016207:Cytokines; C556062:IL10 protein, mouse; D053701:Receptors, Interleukin-10; D016753:Interleukin-10; D007770:L-Lactate Dehydrogenase; C505409:Casp3 protein, mouse; D053148:Caspase 3